Synthesis, characterization, and application of nanohybrid formed by mixing carboxylated cellulose nanocrystal and zinc nitrate hexahydrate by precipitation method using Oxytenanthera abyssinica as raw material

Synthesis, characterization, and application of nanohybrid formed by mixing carboxylated cellulose nanocrystal and zinc nitrate hexahydrate by precipitation method using Oxytenanthera abyssinica as raw material | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Synthesis, characterization, and application of nanohybrid formed by mixing carboxylated cellulose nanocrystal and zinc nitrate hexahydrate by precipitation method using Oxytenanthera abyssinica as raw material Limenew Abate Worku, Rakesh Kumar Bachheti, Mesfin Getachew Tadesse, and 1 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-2225634/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract In this study, cellulose from Oxytenanthera abyssinica was hydrolyzed to create carboxylated cellulose nanocrystals in a solution of citric acid and sulfuric acid. Afterward, nanohybrids were synthesized using carboxylated cellulose nanocrystals, zinc nitrate hexahydrate for photocatalytic degradation, and antibacterial and antioxidant properties. The experimental results were characterized using FTIR, XRD, SEM, and UV-Vis spectroscopy. Data from SEM, XRD, DLS, and FTIR spectra showed that ZnO nanoparticles were loaded on carboxylated CNC to form a nanohybrid of CNC/ZnO with mean nanoparticles size of 164.18 nm and size distribution between 94–351 nm. The data showed CNC/ ZnO nanohybrid had higher antibacterial, photocatalytic and antioxidant activities than CNC. The higher antibacterial activity was observed against both grams positive (Klebsiella pneumonia and Escherichia coli) and gram-negative bacteria (Staphylococcus epidermidis and Staphylococcus aureus) with an inhibition zone of 26.00±1.00 to 41.33±1.15 mm in comparison with Ciprofloxacin. The maximal amount of methylene blue photodegradation (about 91.52%) was seen after 75 minutes of exposure to a UV lamp. 53.151.03% DPPH radical scavenging actives with IC50 value of 117.66 µm/ml were obtained at 125 µm/ml concentration of CNC/ZnO sample. Biomedical and environmental applications of cellulose are limited by its extremely low antibacterial, photocatalytic, and antioxidant properties. Therefore, this study was done to enhance these properties by synthesizing a nanohybrid of cellulose nanocrystals from cellulose produced from Oxytenanthera abyssinica and ZnO inorganic salt. CNC/ZnO nanohybrids Carboxylated cellulose nanocrystal Antibacterial activities Photocatalytic activities Oxytenanthera abyssinica Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 Figure 10 Figure 11 1. Introduction Cellulose is the most important material found in nature, which has been applied in various applications due to its low toxicity, biocompatibility, and biodegradability (Kwok et al. 2017). It can be found in various substances, including tunicate, algae, fungi, natural fibers, wood, and bamboo (Wang et al. 2021). Cellulose is the primary raw material for the preparation of cellulose nanocrystals (CNC)(Reid et al. 2017). For the past 20 years, academic research has focused on CNC due to its biodegradability, superior biocompatibility, high crystallinity, and excellent characteristics, such as large surface area, outstanding mechanical strength, and ease of chemical modification (Håkansson et al. 2014; Thomas et al. 2018). Due to these remarkable characteristics, CNC has much potential in the fields of devices that store energy (Chen et al. 2018; Kim et al. 2019), rheology modifiers (Hubbe et al. 2017; Liu et al. 2017), reinforcing agents (Clarkson et al. 2021; Zheng and Pilla, 2020), in the treatment of wastewater (Abouzeid et al. 2018; Dong et al. 2021), biomedical components (Du et al. 2019; Lin et al. 2019), and electrically flexible materials (Miao et al. 2020; Zhao et al. 2021). However, its applicability is constrained by its poor UV permeability, poor moisture stability, and lack of antioxidant and antibacterial properties. As a result, limitations to the use of CNC in the fields of biomedicine and photocatalysis. The hydroxyl functional groups on the CNC surface, however, serve as reactive platforms that allow chemical modification for the addition of new functional groups to improve the material's antibacterial, antioxidant and photocatalytic capabilities (Tao et al. 2020). Metallic nanoparticles having favorable chemical and physical behavior are essential nanoscale materials successfully exploited in polymer functionalization (Azizi et al. 2014). Inorganic nanoparticles, ZnO nanoparticles are relatively non-toxic, affordable, and have exceptional optical performance properties such as photocatalytic, electrical, antibacterial, and other capabilities (Kołodziejczak-Radzimska and Jesionowski 2014). The utilization of ZnO in wastewater treatment has also recently received attention because of its capacity to degrade contaminants, such as organic dyes in water and heavy metals, removable during the purification of contaminated water (Samadi et al. 2016; Sharma et al. 2019; Guan et al. 2019). Unfortunately, the ZnO NPs small size and high surface free energy quickly clump together. To overcome this drawback, scientists are highly interested in synthesizing ZnO nanoparticles based on another substance, functioning as a carrier to improve the dispersion of ZnO nanoparticles at the nanoscale level (Tomczak et al. 2009). In this regard, combining CNC as template with ZnO nanoparticles has gained popularity, and studies have been conducted to modify and functionalize cellulose nanocrystals to prevent ZnO nanoparticle aggregation(Tomczak et al. 2009; Yang et al. 2016; Yu et al. 2015). There have been few publications on the formation of ZnO nanoparticles on cellulose substrates, even though research on cellulose-based nanocomposite materials is still ongoing. Most of the reported studies require complex synthesis procedures and time-consuming methods to prepare CNC. Since they mostly use inorganic acids (sulfuric acid, nitric acid, hydrochloric acid, etc) to hydrolysis cellulose, there are weak electrostatic interactions between Zn 2+ and OH-groups on CNC. Thus, in this study, CNC/ZnO nanohybrids were synthesized using carboxylated CNC and N 2 O 6 Zn.6H 2 O as starting materials for antibacterial, antioxidant, and photodegradation applications. We use Organic acid (citric acid) to hydrolyze cellulose derived from lowland Ethiopian bamboo ( Oxytenathera abyssinica) as a nanocrystalline cellulose source abundantly in the western part of Ethiopia. 2. Experimental 2.1 Materials and equipment We employed analytical-grade chemicals in our investigation. In this investigation, the main chemicals used were CNC obtained from Oxytenanthera abyssinica, Zinc nitrate (N 2 O 6 Zn.6H 2 O) (99%,FARIDABAD-121005, INDIA), sulfuric acid (98%, India), citric acid anhydrous (CHEMICALS UDYLOG-121001 (India), and sodium hydroxide (ALPHA CHEMIKA, India), sodium chloride (Maharashtra, India). All chemicals were acquired from the Charcos market center found in Addis Abeba, Ethiopia (Rankem India). The following instruments and equipment were frequently employed in these studies: sonicator (Intelligent Ultrasonic Processor), freeze dryer, centrifuges ( Microfuge Centurion Scientific PrO-Analytical C1015), Zeta sizer (Malvern Zeta Nano (ZE3600), Oven, Analytical balance for laboratories (Ceramic-technology weight sensor), dialysis tube, digital hot plate, Stirrer, XRD (SHIMADZU XRD-6000), SEM, TGA 55-TA Instruments and iS50 FTIRS spectrometer, UV-Vis spectrophotometer Perkin Elmer UV–Vis spectroscope (USA). 2.2 The study area Oxytenanthera abyssinica plant species were gathered from Pawe woreda, found in the Metekel zone, the western part of Ethiopia, as shown in Fig. 1. The area is situated between 36°20′ and 36°32′ longitude and 11°12′ and 11°21′ latitude. It is found at 1120 meters above sea level. The woreda has a hot, humid climate with temperatures ranging between 19.4 to 37.6°C, and receives 1586.32 mm of rain annually (Miruts, 2020). Of the total land of Pawe woreda, 30.6% is forest; among these, Oxytenanthera abyssinica is a botanical plant found in forests (Ambawu, 2019). A permition was obtained from the Pawe Woreda office of Agricultural and Rural Development to collect plant material based on support from Addis Abeba Science and Technology University. 2.3 Sample collection Oxytenanthera, abyssinica plants with an average age of three years, were randomly collected from the study area by TAPPI standards from 2002 (TAPPI, 2002). The plant material was gathered and delivered to Addis Abeba University for botanical identification. The identification was carried out by taxonomist Doctor Endale Adam and Mr. Wogayew using the Flora of Eritrea and Ethiopia's taxonomic keys, as well as by comparison with the real specimens. This study has followed international, national, and institutional regulations in using plant components (IUCN, 1989). 2.4 Preparation of cellulose nanocrystal Oxytenanthera abyssinica (COA) cellulose hydrolyzed by citric acid anhydrous ( CAA) using Sulfuric acid (SA) as catalyst to produce the carboxylated CNC samples based on the methods used by Xu et al. (2017). Two grams of COA and (100 mL solution of 90 wt% CAA and 10% SA) was added to form solution. The solution was stirred with the Mixstab TEFAL Swing. The reactions were carried out in a spherical flask using an oil bath at 80 °C for 5 hours with a magnetic stirrer operating at 1000 rpm. After the hydrolysis reactions, hot distilled water (100 mL) was added to halt the process and avoid CAA crystallization. The subsequent step involved centrifuging the mixture for 15 minutes at 1000 rpm. The residue obtained after each centrifugation was rinsed with DI water three times. A dialysis tube was then used to dialyze the sediments until the solution's pH and conductivity were constant with distilled water. Using a probe ultrasonicator, the suspension was sonicated for 15 minutes at 25 kHz after diluting to a consistency of around 1wt% to create a uniformly dispersed aqueous solution known as CNC. 2.5 Preparation of ZnO/CNC nanohybrids CNC has a remarkable ability to absorb metallic cations since it has several hydroxyl groups in its structure. Electrostatic interactions between Zn 2+ and the oxygen atoms of hydroxyls allowed Zn 2+ to be absorbed during the initial phase of the process. After NaOH was added, Zn(OH) 2 was gradually produced. ZnO was produced under thermal conditions, as indicated by scheme1 and Fig. 2 (Azizi et al. 2014). In this research work, nanohybrids of CNC/ZnO were synthesized using a modified version of the technique utilized by Yu et al. (2015). Different weights of 0.1 mol/L aqueous solutions of Zn(NO 3 ) 2 . 6H 2 O was mixed with the carboxylated CNC produced in the above procedure in weight ratios of 0.25, 0.50, 0.75, and 1.00. These four samples were adjusted to a pH of 7 using 0.5 mol/L solutions of NaOH. To thoroughly precipitate Zn 2+ , the mixture was then vigorously agitated while being heated to 80 o C and adding 0.1 M NaOH solutions were drop by drop. The carboxylates (COO-) of CNCs and Zn 2+ were electrostatically attracted to one another, and Zn(OH) 2 precipitated. At 12,000 rpm, the mixture was centrifuged in DI water, at 10 o C, for 20 minutes to eliminate any byproducts and residual zinc species. Following this, the mixture was freeze-dried for 48 hours. To convert Zn(OH) 2 compound formed duet to the reaction of Zn 2+ and OH - (scheme 1) into ZnO, the samples were then dried for an hour at 120 o C. Based on CNC to Zn(NO 3 ) 2 .6H 2 O weight ratio, the four samples are designated CNC/ZnO 1/4 , CNC/ZnO 1/2 , CNC/ZnO 3/4 , and CNC/ZnO 1 to represent CNC/ZnO (25, 50, 75 and 100%) sample respectively. 2.6 Characterization 2.6.1 Zeta potential test Using a Zeta sizer (Malvern Zeta Nano, ZE3600), the CNC and ZnO/CNC nanohybrids zeta potential values were determined in aqueous solution. An aqueous suspension (2.5 mg/mL) of the material, which was diluted to 0.01% was used to measure in triplicate at 25 o C. Table 1 displays the typical zeta potential values of CNC/ZnO nanohybrids. 2.6.2 Carboxyl content analysis Conductometric titration is very important to determine the COOH group concentrationin the CNC/ZnO nanohybrids. 0.1g of dried sample and 10mL of 0.01M of NaCl solution were mixed with 100mL of DI water, and to produce a well-dispersed suspension, the produced solution was vigorously swirled. 0.1 M HCl was added to the mixture to reduce the pH to 2.5–3.0. 0.015 M NaOH solutions were then added to the suspension at a rate of 0.1 ml per drop, bringing the pH up to 11. From conductivity-pH curves, the sample's carboxyl group content was determined. 2.6.3. UV–Vis absorption In the range of 200 to 800 nm, UV–Vis spectrophotometer (Perkin Elmer UV–Vis spectroscope, USA), was utilized to determine the optical properties of MB suspension. Four CNC/ZnO hybrids samples, such as CNC/ZnO 1/4 , CNC/ZnO 1/2 , CNC/ZnO 3/4 , and CNC/ZnO 3/4 were characterized. 2.6.4 Scanning electron microscope The morphologies of the synthesized CNC/ZnO nanohybrids and CNC samples were evaluated by utilizing SEM (high vac. SED, PC-std, 15 kV) at 2.0 kV accelerating voltage at room temperature. Before SEM observation, the diluted suspension was added to dry on a silicon slice. 2.6.5 Fourier transform infrared spectroscopy (FTIR) An FT-IR spectrometer was used to collect the samples’ FT-IR spectra. The spectra were recorded at wave numbers range of 4000-400 cm-1. The FTIR analysis was performed using the IS50 FTIR spectrometer. 2.6.6 X-ray powder diffraction Using monochromatic Cu Ka radiation at k = 1.54056 A in the 2 range of 5-80 at a scan rate of 5 min-1, an X-ray powder diffractometer (SHIMADZU XRD-6000) was used to analyze the crystallite size and morphology CNC/ZnO nanohybrids and CNC. The crystallinity size was calculated using the Scherrer equation (equation 3) (Yu et al. 2012). The current and tension of the X-ray generator were 30 mA and 40 kV, respectively. 2.7 Photocatalytic activity Absorption spectroscopy under UV irradiation was used to analyze the materials' photocatalytic activity by previously reported procedures Fallah et al. (2011) and Zhai et al. (2014) depending on the photodegradation response of methylene blue (MB) dye. MB was exposed to high-intensity (365 nm, 115V-60 Hz, 2.5 A, 100 W) Lamp UV irradiation to examine CNC/ZnO nanohybrid photocatalytic properties. In 500 ml of deionized water, 10 ppm stock solution of MB was produced, and then 2 mg of different samples was added to 60 ml of 10ppm dye solution. The solution was stirred with a magnetic stirrer for 15 minutes in the dark to reach the system's adsorption equilibrium before irradiation. The mixture was exposed to UV irradiation for 15 min time intervals (15, 30, 45, and 75). The testing samples (CNC, CNC/ZnO 1 , CNC/ZnO 3/4 , CNC/ZnO 1/2 , and CNC/ZnO 1/4 ) were removed from the colloidal mixture, and cleaned supernatant was obtained by centrifuging for 15 minutes at 5,000 rpm. The Perkin Elmer UV-Vis spectroscope (USA) was then utilized to determine the absorbance spectra of the supernatant from 350 to 850 nm wavelength. The absorbance value at 660 nm was used to calculate the dye concentration during the degradation process. To calculate the percentage of MB degradation, the equation below was used. Degradation rate = …………………. (1) Where: C t and C 0 are the concentrations of the MB after and before UV radiation, respectively. 2.8 Antioxidant activities The DPPH radical scavenging assay described by Blois (1958) and Desmarchelier et al. (1997) was used to examine the antioxidant potential of samples to scavenge free radicals. The color change of a methanolic solution of 2, 2-diphenyl-1-picrylhydrazyl (DPPH) was utilized to assess the potential scavenging activities of free radicals of the CNC/ZnO samples. When DPPH is dissolved in methanol, it generates a violet or purple color, with antioxidants' actions cause to fade to various shades of yellow color. In order to investigate the antioxidant properties of the prepared sample, Ascorbic acid was utilized as a standard to measure the percentage of DPPH radical scavenging activity using equation 2. A 0.1 mM DPPH solution in methanol was initially dissolved. Subsequently, 2.4 mL of this solution was added to 1.6 mL of CNC/ZnO nanohybrid sample dissolved in methanol at various concentrations (25 - 125 g/mL). After fully vortexing the mixed solution, the reaction mixture was kept at room temperature for 30 minutes. At 517 nm, the mixture's absorbance was determined spectrophotometrically. % DPPH radical scavenging activities = ………………(2) Where: A 1 and A 0 are UV absorbance of samples and control, respectively 2.9 Antibacterial susceptibility testing of sample The in vitro bactericidal activity of CNC/ZnO 1 , CNC/ZnO 3/4 , CNC/ZnO 1/2 , and CNC/ZnO 1/4 was investigated using the disc diffusion method. The dry samples were first dissolved in sterilized distilled water (5 mL) to achieve the necessary test concentration of 0.25, 0.50, 0.75, and 1.00 mg/ml. 5 mm-diameter discs of Whatman's No. 1 filter paper were produced using a paper borer. These discs were exposed for 24 hours to each test concentration. The discs were taken out and dried in an aseptic condition. A pure culture of two gram -ve bacteria species such as Klebsiella pneumonia and Escherichia coli , and two gram +ve photogene including Staphylococcus epidermidis and Staphylococcus aureus were incubated for 72 hours to make the bacterial solution. The suspension was made using sterilized distilled water. Using a spectrophotometer, the suspension's optical density was adjusted to 0.132 at 600 nm. This is equivalent to 0.5 McFarland turbidity standards. At this turbidity level, 1.5 × 108 CFU/mL of bacteria is present. The Muller-Hinton Agar medium was aseptically inoculated with around 0.5 mL of the bacterial suspension, and the spreader was used to disseminate it evenly. Sensitive discs of ciprofloxacin 30 µg/mL concentration were used as standard controls. Within 15 minutes, the dried discs were applied to the inoculated Petri dishes. All the Petri plates were incubated at 37ºC. Each test concentration was examined three times during the antibacterial susceptibility testing process. The antibacterial activity of extracts was assessed using the zone of inhibition's diameter. Using a transparent ruler or meter, the inhibitory zone was seen and measured in millimeters. 2.10 Statically analysis Origin 8 software was used to analyze the results variance (one-way ANOVA). All measurements were done three times (n=3), and the results are the average of three repetitions with standard deviations (SD). A confidence limit of P value less than or equal to 0.05 was used to determine significance. 3. Result And Discussion 3.1 Size distribution, carboxyl content, and zeta potential The DLS experiment was performed on a CNC/ZnO suspension made from CNC. The resulting size distribution is shown in Table 1. It was found that the CNC sample had the shortest average particle size (94.2 - 259 nm) than CNC/ZnO 1/4 (103.4 - 281 nm), CNC/ZnO 1/2, (122.4- 295.3 nm), CNC/ZnO 3/4 (128.4-301.4 nm) and CNC/ZnO 1 (119 to 341.2 nm) samples. This finding indicates that hydrolysis of COA by CAA is more likely to produce smaller size cellulose nanocrystals. However, the size of the samples increased as ZnO nanoparticles were added to CNC. CNC/ZnO 1 samples displayed the biggest size compared to the other samples. Since more ZnO nanoparticles grow on the CNC surface due to more Zn 2+ being coupled with CNC. As shown in Table 1, the size of CNC/ZnO samples slightly increased in the order of CNC, CNC/ZnO 1/4 , CNC/ZnO 1/2 , CNC/ZnO 3/4 and CNC/ZnO 1 with the size distribution of 94.2 - 259 nm, 103.4 - 281 nm, 122.4- 295.3 nm, 128.4- 301.4 nm, and 1119 to 341.2 nm respectively. The results of the carboxyl group content of the CNC/ZnO nanohybrid obtained based on the conductometric titration method are shown in Table 1. The highest concentration was found for CNC samples (0.75± 0.08mmol/g) due to more carboxyl groups. The carboxyl content of the CNC/ZnO 1 showed the smallest amount (0.15± 0.24) than CNC/ZnO 3/4 (0.37± 1.01), CNC/ZnO 1/2 (0.58±0.78) and CNC/ZnO 1/4 (0.71± 2.01). This is due to more hydroxyl groups in CNC enclosed by ZnO nanoparticles. When the concentration of Zn 2+ increased, the reaction solution contained many Zn 2+ ions and reacted with more hydroxyl groups of the dissolved CNC, this characteristic decreased the carboxyl content. The average value of zeta potential acquired for CNC, CNC/ZnO 1/4 , CNC/ZnO 1/2 , CNC/ZnO 3/4 , and CNC/ZnO 1 was -33mV, -13.7mV,-11.7mV, -10.4mV and -9.25mV, respectively (Table 1). All CNC/ZnO samples exhibited lower zeta potential compared to CNC. This is due to the carboxyl group found in CNC participating in the ZnO nanoparticles preparation system. During the preparation of CNC via esterification reaction, negatively charged nanoparticles are produced due to carboxyl groups on their surface. This affects the tendency of the zeta potential value of the CNC sample (Yu et al. 2016). CNC/ZnO 1 has the lowest absolute value of zeta potential (-9.25 Mv), followed by CNC/ZnO 3/4 with a value of -10.4 Mv. However, CNC/ZnO 1/4 has the highest value (-13.7 Mv) among the four nanohybrid samples. This is because the zeta potential of the CNC is consistent with the carboxyl content of CNC samples (Table 1). As the content of COOH increases, the absolute value of zeta potential also increases(Yu et al. 2016). CNC had the highest absolute zeta potential (-33 mV), indicating the highest repelling force between CNC samples driven by the most considerable carboxyl content. Table 1 zeta potential, carboxyl content, and size distribution of CNC/ZnO nanohybrids Samples Zeta potential Carboxyl content Size (d.nm) from DLS data CNC -33 mV 0.75± 0.19 a 94.2 - 259 nm CNC/ZnO 1/4 -13.7 mV 0.71± 2.01 b 103.4 - 281 nm CNC/ZnO 1/2 -11.7 mV 0.58± 0.78 c 122.4- 295.3 nm CNC/ZnO 3/4 -10.4 mV 0.37± 1.01 d 128.4- 301.4 nm CNC/ZnO 1 -9.25 mV 0.15± 0.24 e 1119 to 341.2 nm All data were examined in triplicate, and the mean value ± SD was taken and written in the table. The identical alphabetical letter indicates that there are no statically significantly different (P>0.05) between values in the same column. 3.2 Scanning Electron Microscope (SEM) Analysis Fig. 3 displays ROA, COA, CNC, and CNC/ZnO samples in SEM images. The SEM image shows the differences in the fiber surfaces between ROA and COA by observing images after and before the bleaching process. The image confirmed that the surface of COA fibers is smoother and has less solid aggregate than ROA fiber. Additionally, the COA exhibit decreased aggregation, suggesting that the bleaching procedure was successful in removing a sizable portion of the amorphous mass from the fiber surfaces, such as low molar mass polysaccharides, impurities, and lignin reported previously by César et al. (2015); Khan et al. (2009) and Gültekin (2016). ROA showed a larger size (23.0 to 8.34 µm) than COA (18.05 to 4.01µm) samples. SEM images of ZnO/CNC and CNC show that the morphology of CNC is similar to a rod-shaped size with a smaller size (31 to 259 nm) due to the acid hydrolysis influence of chemicals in the synthesis process. Following the precipitation of CNC and Zn 2+ ions in the CNC/ZnO 1/2 sample, ZnO nanoparticles with a mean diameter of 164.18 nm and size distribution of 94–259 nm were formed on the surface of CNC. The average diameter of ZnO nanoparticles increased to 183.5 nm in a CNC/ZnO 1 sample with a size range of 128 to 351 nm due to an increase in Zn 2+ ion concentration. As more Zn 2+ ions become immobilized on the CNC surface, causes the number of ZnO particles in CNC increases. 3.3 X-ray powder diffraction ( XRD ) Fig. 4 displays the CNC and CNC/ZnO nanohybrid's XRD image. The cellulose I characteristic peaks are visible in the CNC's XRD pattern at 2θ = 15.68°, 22.58°, and 34.54° (French AD 2014). In addition to the cellulose-specific peaks, The ZnO/CNC samples also show additional peaks at 69.42°, 67.5°, 62.54°, 56.76°, 47.68°, 36.38°, 34.52°, and 31.98°, which are assigned to the values (201), (112), (103), (110), (102), (101), (002), and (100), respectively (Sirvio¨ JA et al. 2014; Ul-Islam et al. 2014). This is an indication of the formation of nanohybrids. The crystal structure of the ZnO is revealed by the prominent intensity diffraction peaks in the XRD scheme (Sharma et al. 2019; Guan et al. 2019). Fig. 4 shows two-phase structures that show CNC/ZnO (#) and CNC (*) were observed. This showing using CNC, ZnO nanohybrid has been synthesized effectively. The low-intensity peaks of CNC/ZnO nanohybrids compared to the XRD peak of pure ZnO nanoparticles showed the deposition of ZnO NPs on the CNC surface. The findings further demonstrate that the existence of ZnO crystals does not affect the cellulose crystal structure. Three CNC/ZnO nanohybrid samples have similar XRD patterns. This demonstrated the efficient one-step ZnO synthesis on CNC in a successful manner. These profiles indicated that the presence of well-crystalline ZnO has not changed the crystal structure of the cellulose matrix. The Figure further demonstrated that, with rising Zn 2+ ion concentrations, ZnO peaks get broader and more powerful over time. This suggests that the CNC/ZnO nanohybrids' crystal size and crystallinity have increased. Using debye-Scherrer technology, the crystal size (D) of the CNC/ZnO and CNC, structures were determined from the XRD data using equation (3). Where: β is the integral breadth of the maximum complete width (FWHM), λ is X-ray radiation's wavelength (k=0.94), D hkl is the size of a crystallite in nanometers as viewed from the crystal's(hkl) plane, (π/180) is the correction factor in changing β into radians, and θ is the scattering angle, The predicted size of the CNC hybrid's ZnO crystal was 11.5nm, 10.7nm, and 9.8nm for CNC/ZnO 1 , CNC/ZnO 3/4, and CNC/ZnO 1/2 , respectively. The three samples' estimated crystallite sizes match those in Fig. 4 XRD patterns because the purer ZnO is typically associated with larger crystal sizes, which are typically associated with sharper intensity peaks., In contrast, the CNC/ZnO spectrum's smaller and wider peaks are connected to a smaller crystal size (Mumalo-Djokic et al. 2008; Taunk et al., 2015). These intensity peaks and crystal planes showed that ZnO nanoparticles effectively formed on the CNC surface. 3.4 Ultraviolet-visible (UV-Vis) The optical properties of CNC/ZnO nanohybrids with various Zn 2+ concentrations were examined by utilizing a UV-Vis spectrophotometer. Fig. 5 shows the UV-Vis absorption peak of the CNC and CNC/ZnO nanohybrids. It was found that the CNC's spectra lacked any noticeable peaks between 300 and 700 nm. However, the UV–Vis peak showed a strong peak before 400 nm for all ZnO/CNC samples. The absorption bands for the CNC/ZnO 1/4 , CNC/ZnO 1/2 , CNC/ZnO 3/4 , and CNC/ZnO 1 samples were 363, 366, 372, and 376 nm, respectively. ZnO's basic band gap absorption, which happens when an electron transitions from the valence band to the conduction band (O2p → Zn3d), is responsible for these peaks (Zak et al. 2011). This shows that ZnO nanoparticles have formed on the surface of CNC. It is intriguing to observe that the larger ZnO caused the absorption band to move toward the red (redshift). This suggests that when the Zn 2+ ion concentration increases, more significant ZnO nanoparticles might be produced. According to the plot of Tauc shown in Fig. 5(b), the band gaps for the samples CNC/ZnO 1/4 , CNC/ZnO 1/2 , CNC/ZnO 3/4 , and CNC/ZnO 1 are 3.32, 3.29, 3.21, and 3.07 eV, respectively. The sample band gaps estimated from (αhʋ)2 versus (hʋ) plot match with the mode of Kubelka-Munk (Yu et al. 2008). 3.5 Fourier transform infrared spectroscopy (FTIR) The identification of functional group and bond structure determination of the CNC/ZnO nanohybrids samples was examined by FTIR instrument in the peak range of 400 and 4000 cm-1 (Fig. 6). Peaks at 3315-3340 cm-1 in the CNC/ZnO nanohybrids and CNC spectra were attributed to the O-H stretching mode (Azizi et al. 2013). After adding ZnO to cellulose, the strength of the O-H stretching vibrations weakened for CNC/ZnO 3/4 and CNC/ZnO 1, as shown in Fig. 6. This suggests oxygen atoms participated in the bonding interaction with ZnO and weakened the O-H bond. The peak at 1435 cm-1 was assigned to the CH2 vibration and taken as the crystallization band for each cellulose material, while sharp peak was indicated to C-O stretching for the CNC and CNC/ZnO samples. Its intensity decreases as the concentration of ZnO increases. According to Lu and Hsieh (2010), the peak at 1,650 cm -1 is because of the C-O-C bond stretching of glucose and pyranose ring skeletal vibration, but the peak at roughly 1,065 cm -1 is caused by the O-H bending of a water molecule (Cherian et al. 2008). The band intensity (1.721cm -1 ) for the C=O stretch decreased in intensity compared to the CNC peak intensity. This resulted from the potent interaction between the COOH groups on the CNC surface and the ZnO NPs. Compared to CNC, more absorption peaks at 600–400 cm were found in ZnO/CNC nanohybrids, and these peaks were linked to Zn–O stretching modes (Azizi et al. 2013; Wei et al. 2013). The Zn-O peaks of ZnO/CNC 1 , ZnO/CNC 3/2 , and ZnO/CNC 1/2 were located at 435, 432, and 412 cm-1, respectively. This verifying ZnO was successfully synthesized on the CNC template (Azizi et al. 2013; Zhang et al. 2013). The lack of a peak in the CNC sample between 400 and 450 cm-1 indicates that ZnO is not present in the sample. With increasing Zn 2+ ion concentration, a little shift of the Zn-O stretching bands to higher wavenumbers was observed because of the lattice structure of the ZnO nanoparticles. The absorption peak at 2900 cm -1 , is related to the C-H vibration of sp3-hybridized carbon. This peak vanished when the CNC/ZnO nanohybrid was synthesized (Oyewo et al. 2019). This peak's intensity also decreased with ZnO loading increase (Fig. 6). The decrease in intensity of the peak indicates that ZnO is present or loaded to the CNC lattice. A similar observation was made in the work of Ali et al. (2016) and Keshk and Hamdy (2019) using nanocomposites made of cellulose and ZnO. 3.6 Application of CNC/ZnO nanohybrids 3.6.1 Photocatalytic activity By using solid-phase photodegradation MB dye, the photocatalytic activity of four different samples, including CNC/ZnO 1 , CNC/ZnO 3/4 , CNC/ZnO 1/2 , and CNC/ZnO 1/4 (Fig. 7), was investigated. The degradation of MB caused by exposure to UV radiation was used to determine the effectiveness of CNC/ZnO samples as photo-catalyst activities. The adsorption-desorption studies were carried out in complete darkness for 5 minutes, and the absorption spectra after this adsorption-desorption step are reported as "0 min". At various time intervals and under the identical circumstances, the photocatalytic activity of CNC was also assessed for comparison. To determine how much UV light could potentially degrade MB, a blank test was run to see how much MB would degrade without a photocatalyst. Fig. 7a, 7b, and 7c illustrate the photocatalytic capability of CNC/ZnO nanohybrids to degrade MBs when exposed to UV light in a 75-minute irradiation time. The result showed that in samples containing CNC solely, no notable changes in the UV absorption band of MB were seen after 75 minutes of UV exposure. Fig. 7d shows the MB degradation when it reacted with different CNC/ZnO samples. The degradation increase in the order of CNC/ZnO 1 , CNC/ZnO 3/4 , CNC/ZnO 1/2 , and CNC/ZnO 1/4 . The Fig. also shows that there is no significant difference in absorbance between CNC and MB; this showed that CNC has the lowest capacity to reduce the absorbance of MB. Fig. 7d also shows the MB's absorbance reduction due to the addition of CNC and CNC/ZnO samples. Based on the Fig.s, the absorption peak of MB (2.23) reduced to 0.79, 0.93, 1.07, and 1.38 for CNC/ZnO 1 , CNC/ZnO 3/4 , CNC/ZnO 1/2 , and CNC/ZnO 1/4 respectively. Less MB degradation was evident with higher UV absorption values. The lowest absorption peak (highest degradation) is shown in CNC/ZnO 1 and the most significant (lowest degradation) is shown in CNC/ZnO 1/4 . This is related to the concentration of ZnO concentration present in the sample. As the amount of ZnO increases, the chance of e - and h + reacting with O 2 and H 2 O to generate free radical(OH - ) and O 2 - also increases (Fig. 9); this might take part in the direct oxidative breakdown of MB dye (Qi et al. 2017; Lefatshe et al. 2017; Balcha et al. 2016). As seen in Fig. 8, the samples' exposure period to UV light impacts MB deterioration. To measure the effect of MB degradation with time, we measured the UV absorbance of the samples every 15-minute interval for 75 minutes. The result showed that the samples' absorbance decreased when the reaction time increased—however, the rate of degradation over time increased. As shown in Fig. 8, CNC/ZnO 1 has the highest degradation rate, while CNC/ZnO 1/4 has the lowest degradation rate every 15, 30, 45, 60, and 75 minutes of exposure to UV irradiation. Fig. 8b demonstrate that, after 75 min of UV irradiation, ungraded MB for CNC/ZnO 1 , CNC/ZnO 3/4 , CNC/ZnO 1/2 , CNC/ZnO 1/4 and CNC samples were 8.48, 19.65, 36.42, 45.88 and 83.48% respectively. Since ZnO was absent from the CNC sample, the 75-minute UV exposure exhibited no appreciable impact on the MB UV absorption band. After a 75-minute reaction, the lowest percentage of MB degradation (16.52%) was found in CNC, which had a lower degradation rate than CNC/ZnO 1 (91.52%), CNC/ZnO 3/4 (80.348%), CNC/ZnO 1/2 (63.58%), and CNC/ZnO 1/4 (54.12%) (Fig. 8a). According to the Figure after being exposed to UV radiation for 75 minutes in CNC/ZnO 1 nanohybrid, roughly 91.52% of the MB dye rapidly decomposed. This finding suggests that ZnO/CNC 1 nanohybrids have strong electrical interactions with ZnO nanoparticles that are well dispersed on the CNC surface. These characteristics possessed the sample to have higher photocatalytic activity than other samples. This photocatalytic performance in the present study was more effective than the photocatalytic activity (less than 90%) of CNC/ZnO nanohybrids made by Nang An et al. (2020) in 75 minutes of UV exposure time and comparable photocatalytic activities (about 90%) have been seen in the work of Yu et al. (2015) in 75 minute time. Fig. 9 illustrates a potential mechanism for the CNC/ZnO nanohybrids photocatalytic activity according to the above results. ZnO can make photogenerated electron-hole pairs by absorbing UV light. The resulting photogenerated hole (h+) and electron (e-) could go to the ZnO nanoparticles' surface, interacting with both H 2 O and O 2 that have been absorbed on the surface of ZnO to produce O 2 - and OH, which could take part in the direct oxidation that leads to dye degradation (Huang et al. 2014; Zhai et al. 2014). 3.6.2 Determination of antioxidant activity Using the DPPH radical scavenging method As a result of its sensitivity to detect active substances at low doses, the 2,2-Diphenyl-1-picrylhydrazyl (DPPH) assay is frequently employed to test for antioxidant activity (Tettey and Shin 2019). Since DPPH is a nitrogen-centered free radical, any substance significantly reducing DPPH levels may also lower the amount of other reactive nitrogen species (Tettey and Shin 2019). Our findings show that the CNC/ZnO nanohybrid could dose-dependently quench DPPH free radicals at 25, 50, 75, 100, and 125 g/ml concentrations. According to the data in Table 2, CNC/ZnO 1 had the highest percentage inhibition value (25 g/mL, 11.09% 1.21; 50 g/mL, 21.43% 2.11; 75 g/mL, 32.07% 0.74; 100 g/mL, 42.51% 0.62; and 125 g/mL, 53.15% 1.03) than the other samples. This demonstrated that it had higher free radical scavenging activity levels than the other samples. CNC/ZnO 1 has not shown a significant (p percentage inhibition compared to CNC/ZnO 3/4 . However, there is a significant (p percentage inhibition value in the rest of the samples. CNC's value is the smallest compared to CNC/ZnO 1 , CNC/ZnO 3/4 , CNC/ZnO 1/2, and CNC/ZnO 1/4 samples. This is an indication that CNC has the smallest antioxidant activities. All samples in table 2 showed a much lower percentage inhibition value than that of the AA standard (125 µg/ml, 93.75 %±0.11). Table 2 Percentage inhibition of different CNC/ZnO samples Samples Concentration ration (µg/ml) 25 50 75 100 125 CNC/ZnO 1 11.09±1.21 a 21.43±2.11 a 32.07±0.74 a 42.51±0.62 a 53.15±1.03 a CNC/ZnO 3/4 10.78±1.31 a 21.21±1.91 a 31.73±0.91 a 42.06±0.57 a 52.58±0.65 a CNC/ZnO 1/2 9.10±0.45 b 17.73±0.34 b 26.48±0.34 b 35.33±0.56 b 44.08±0.34 b CNC/ZnO 1/4 6.22±0.26 c 12.25±1.45 c 18.17±2.45 c 24.30±0.54 c 30.12±0.76 c CNC 1.21±0.23 d 2.31±0.43 d 3.41±0.19 d 4.51±0.27 d 5.61±0.39 d AA 51.15±0.65 e 62.42±2.34 e 74.53±0.97 e 80.61±0.32 e 93.75±0.11 e All data were examined in triplicate, and the mean value ± SD was taken and written in the table. The identical alphabetical letter indicates that there are no statically significantly different (P>0.05) between values in the same column. AA= ascorbic acid The IC50 values of CNC/ZnO samples are presented in Fig. 10. Their value ranged from 117.66 ± 2.07μg/ml to 554.30 ± 2.07μg /ml. All CNC/ZnO samples had IC50 values that were greater (P < 0.05) than ascorbic acid, indicating that they are the least effective in scavenging DPPH radicals compared to standards. CNC samples without ZnO have the largest (554.30± 2.11), and AA has the lowest (19.30 ±1.03) IC50 value. There is no significant (P > 0.05) IC50 value difference between CNC/ZnO 1 and CNC/ZnO 3/4 samples. Since the antioxidant activities and IC50 value have inversely proportional values, the results showed that CNC had the lowest antioxidant activities, whereas CNC/ZnO 1 had the highest antioxidant activities. The results from both % inhibition and IC50 values demonstrated that when Zn 2+ concentrations increase, the antioxidant activities of the samples to scavenge free radicals also increase. As ZnO nanoparticle concentrations rise, more DPPH free radicals are quenched. This results in to increase the antioxidant activities. Similar work was done by Ali et al. (2016). Their work showed that ZnO-Cellulose showed lower DPPH free radical scavenging activities (14.85%) than the present work. The study also revealed that DPPH scavenging activity was shown to rise with a rise in nanoparticle concentrations. This characteristic is also observed in this work. 3.6.3 Antibacterial activities The lack of antibacterial activities in cellulose may restrict its usage in biomedical and environmental applications. This is why researchers are initiated to synthesize zinc nanocomposites with cellulose for antibacterial activities (Azizi et al. 2014; Ul-Islam et al. 2014). By converging cellulose into CNC and preparing CNC/ZnO. We made cellulose to have antibacterial activities (Fig. 11). In this study, gram-negative bacteria species such as Escherichia coli and Klebsiella pneumonia , as well as gram-positive bacteria including Staphylococcus aureus and Staphylococcus epidermidis , were used to investigate the antibacterial efficacy of the CNC/ZnO nanohybrids. The CNC was used as a control sample. The Ciprofloxacin drug was employed as a standard sample in the Agar well diffusion method to examine the antibacterial activity. The disc diffusion method was used to assess the antibacterial activity. It was shown that the inhibition zones produced by CNC/ZnO nanohybrids against Escherichia coli and Klebsiella pneumonia ranged from 32.33 2.51 to 41.33 1.15 and 31.66 3.51 to 41.00 1, respectively . For gram-positive bacteria species such as Staphylococcus aureus and Staphylococcus epidermidis, zone inhibition was observed in the range of 26.00±1.00 to 40.33±2.08 and 31.22±1.52 to 38.66±1.15 respectively. The standard drug in this investigation, Ciprofloxacin, demonstrated a 30 00±0.00 zone of inhibition for testing four bacterial species. The size of the growth-inhibiting ring used to combat Staphylococcus aureus against four different samples such as CNC/ZnO 1/4 , CNC/ZnO 1/2 , CNC/ZnO 3/4, and CNC/ZnO 1 were 26.00± 1.00, 32.33± 2.51, 33.33± 2.88, and 40.33± 2.08 mm, respectively. This showed that as the concentration of Zn 2+ increases, the antibacterial activities of Staphylococcus aureus also increase. However, this uniform trend is not observed for the other three bacteria species, such as Escherichia coli, Klebsiella pneumonia, and Staphylococcus epidermidis (Fig. 11). There was no significant difference (P in the value of disc diffusion between Escherichia coli and Klebsiella pneumonia, almost in all concentrations. This showed that the antibacterial properties between these two species are almost the same. The inhibition zone of CNC/ZnO 1 (16.3±3.21mm), CNC/ZnO 3/4 (17.3±2.51 mm), CNC/ZnO 1/2 (17.3±2.51 mm), and CNC/ZnO 1/4 (17.3±2.51 mm) against Escherichia coli and the inhibition zone of CNC/ZnO 1 (16.3±3.21mm), CNC/ZnO 3/4 (17.3±2.51 mm), CNC/ZnO 1/2 (17.3±2.51 mm) and CNC/ZnO 1/4 (17.3±2.51 mm) against Klebsiella pneumonia were statistically significant (P<0.05) greater than inhibition zone of the corresponding samples of gram-positive bacteria species such as Staphylococcus aureus and Staphylococcus epidermidis . This showed that gram-negative bacteria respond more positively to antibacterial activities than gram-positive bacteria species. Escherichia coli and Klebsiella pneumonia , there was no statistically significant (P < 0.05) difference among the inhibition zone of CNC/ZnO 1 , CNC/ZnO 3/4, and CNC/ZnO 1/4 . However, in Staphylococcus aureus and Staphylococcus epidermidis there was a statistically significant (P < 0.05) difference among inhibition zone against CNC/ZnO 1 , CNC/ZnO 3/4 , CNC/ZnO 1/2 and CNC/ZnO 1/4 . The inhibition zone of the standard drug Ciprofloxacin (30.00 ± 1.00) exhibited the lowest value except for the value of CNC/ZnO 1 against Staphylococcus aureus (26.00± 1.00). This showed that the synthesized CNC/ZnO samples have high antibacterial activities. The data in table 3 showed that as the concentration of ZnO nanohybrids increased, the % inhibition of the samples also increased. This showed that antibacterial activities are directly dependent on concentration. The use of CNC/ZnO nanohybrids against Staphylococcus aureus and Escherichia coli has been reported by Abdalkarim et al. (2018b) to inhibit the growth of bacteria and reduce bacterial counts. Despite using diluted nanocomposites, their findings indicated that the bacteria were inhibited in 4.5 and 3mm zones, respectively. This value is too small compared to our work. In another similar work by Abdalkarim et al. (2018a), zones of inhibition for the antibacterial activity of CNC/ZnO nanohybrids against Staphylococcus aureus and Escherichia coli were also observed to be 3.0 to 5.1 mm and 4.1 to 4.9 mm, respectively. This value is also small compared to our value. Yu et al. (2015) discovered effective CNC/ZnO nanohybrid antibacterial activity against Staphylococcus aureus and Escherichia coli , with the diameter of the growth inhibition ring measuring 4.5 and 4.3 mm, respectively. This value is also too small compared to the value found in our work (Fig. 11). Due to the greater surface area of ZnO nanostructures, more ROS are produced. The bacteria become oxidized by the metal component, which renders their proteins inactive, decreases cell permeability, and finally results in their death. The generated ROS may penetrate and directly damage bacteria's cell walls, causing peroxidation of the organism's PUFA phospholipids and bacterial death (Wang et al. 2017; Sawai et al. 1996). Additionally, another bactericidal mechanism might result from electromagnetic interaction between the pathogen and the nanoparticles, which would halt the bacteria's activity (Mohd Yusof et al. 2019). Table 3 The zone of inhibition that CNC/ZnO showed against four bacteria pathogens such as Staphylococcus epidermidis, Staphylococcus aureus, Escherichia coli, and Klebsiella pneumonia, Bacteria species Trial Samples Ciprofloxacin (standard) CNC/ZnO 1 CNC/ZnO 3/4 CNC/ZnO 1/2 CNC/ZnO 1/4 30.00± 00 Escherichia coli (-ve) 1 st 30 42 40 42 2 nd 32 40 40 40 3 rd 35 41 42 42 Average 32.33 ± 2.51 a 41± 1.00 b 40.66 ± 1.15 b 41.33± 1.15 b Klebsiella pneumonia (-ve) 1 st 28 38 43 40 30.00± 00 2 nd 35 40 45 41 3 rd 32 41 40 42 Average 31.66± 3.51 a 39.66± 1.52 b 42.66± 2.51 b 41.00± 1.00 b Staphylococcus aureus (+ve) 1 st 25 30 30 38 30.00± 00 2 nd 27 35 35 42 3 rd 26 32 35 41 Average 26.00± 1.00 a 32.33± 2.51 b 33.33± 2.88 b 40.33± 2.08 c Staphylococcus epidermidis 1 st 33 32 38 38 30.00± 00 2 nd 30 30 35 40 3 rd 31 30 38 38 Average 31.22± 1.52 a 30.66± 1.15 a 37± 1.73 b 38.66± 1.15 b Conclusion This research study synthesized CNC/ZnO through a simple and single-stage process. Data from SEM, XRD, DLS, and FTIR spectra showed that ZnO nanoparticles were loaded on carboxylated CNC to form a nanohybrid of CNC/ZnO with a mean size of 164.18 nm in the range between 94–351 nm. ZnONPsare distributed around the CNC because of the electrostatic interaction between the Zn 2+ ion and the carboxyl group of the CNC. The synthesized CNC/ZnO nanohybrids showed high photocatalytic activities, with a 90% degradation rate of MB. The nanohybrid samples also showed higher antibacterial than CNC. All the samples exhibited high antibacterial activities against both grams positive ( Klebsiella pneumonia and Escherichia coli ) and gram-negative bacteria ( Staphylococcus epidermidis and Staphylococcus aureus) with inhibition zone in the range of26.00±1.00 to 41.33± 1.15 mm compared to Ciprofloxacin. The result also showed that CNC/ZnO nanohybrids have higher antioxidant activities than CNC. In the CNC sample, the lowest DPPH radical scavenging activities, 5.61±0.39, were observed. The highest % inhibition of DPPH (53.15±1.03%) and the lowest IC50 value (117.66µm/ml) were observed in CNC/ZnO 1 sample. The above data showed that ZnO/CNC nanohybrid could be applied in dye removal, wastewater treatment, and antibacterial activity. ZnO/CNC nanohybrid showed weaker antioxidant activity in this study, necessitating further study in this area. Declarations Acknowledgments The Department of Industrial Chemistry at Addis Ababa Science and Technology University provided the opportunity for the authors to conduct this research. The only Doctoral Dissertation Research provided by Addis Ababa Science and Technology University, Ethiopia, was used. Ethical approval Not applicable Competing interests The authors declare no competing interests Authors contributions All authors contributed to the study conception and design. Material preparation, data collection and analysis were performed by Limenew Abate Worku. The first draft of the manuscript was written by Rakesh Kumar Bachheti and Mesfin Getachew Tadesse. Archana Bachheti prepare different table and figures. All authors commented on previous versions of the manuscript. All authors read and approved the final manuscript. All authors also worked on revision of the article. Data availability All data generated or analyzed during this study are included in this paper Funding This study was financially supported by Addis Ababa science and Technology University. No external funding available References Abdalkarim SYH, Yu HY, Wang C, Huang LX, Yao J (2018) Green synthesis of sheet-like cellulose nanocrystal–zinc oxide nanohybrids with multifunctional performance through one-step hydrothermal method. Cellulose 25(11):6433-6446. 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Zhai J, Sun L, Yu H, Li H, Zhang X, Yang H, Xu J (2014) A facile approach of fabricating graphene-encapsulated ZnO microspheres and their synergic effect on photocatalytic performance. J. Nanoparticle Res 16(6):1-10. Zhang G, Liu Y, Morikawa H, Chen Y (2013) Application of ZnO nanoparticles to enhance the antimicrobial activity and ultraviolet protective property of bamboo pulp fabric. Cellulose 20(4):1877-1884. Zhao D, Zhu Y, Cheng W, Chen W, Wu Y, Yu H (2021) Cellulose‐based flexible functional materials for emerging intelligent electronics. Adv Mater 33(28):2000619. Zheng T, Pilla S: Melt processing of cellulose nanocrystal-filled composites (2020) Toward reinforcement and foam nucleation. Ind Eng Chem Res 59(18):8511-8531. Scheme 1 Scheme 1 is available in the Supplementary Files section. Additional Declarations No competing interests reported. Supplementary Files GA.png Scheme1.png Scheme 1: Formation of ZnO mechanism in CNC Cite Share Download PDF Status: Posted Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-2225634","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":148794737,"identity":"24298ecb-30e1-408c-91e9-37245ddcd023","order_by":0,"name":"Limenew Abate Worku","email":"","orcid":"","institution":"Addis Ababa Science and Technology University","correspondingAuthor":false,"prefix":"","firstName":"Limenew","middleName":"Abate","lastName":"Worku","suffix":""},{"id":148794738,"identity":"30f4cae6-ff8c-4713-9d74-49e658419853","order_by":1,"name":"Rakesh Kumar Bachheti","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA3klEQVRIiWNgGAWjYDACHh4GBsaGAwwMzMxAgkFChngtPMxsCSAtPCRoYeAxAPMJ6jDvOXvww88dd+Ts2Xk+v7pRY8HDwH746AZ8WmTO9iVL9p55ZszDzLvNOucY0GE8aWk38GmR4OcxkGZsO5zYA9RinMMG1CLBY0ZIi/FvoJb6HmaeZ8Y5/4jRwttjBrIlgYeZh/lxbhsxWnjOpVn2th027DnMZsac2yfBw0bQLzy5h2/8bDssz95/+PHnnG91cvzsh4/h1YIM2CTAJLHKQYD5AymqR8EoGAWjYOQAAHJ8QqqIdnHYAAAAAElFTkSuQmCC","orcid":"","institution":"Addis Ababa Science and Technology University","correspondingAuthor":true,"prefix":"","firstName":"Rakesh","middleName":"Kumar","lastName":"Bachheti","suffix":""},{"id":148794739,"identity":"5240ea02-d1a9-4bef-ab1e-25f47d12e921","order_by":2,"name":"Mesfin Getachew Tadesse","email":"","orcid":"","institution":"Addis Ababa Science and Technology University","correspondingAuthor":false,"prefix":"","firstName":"Mesfin","middleName":"Getachew","lastName":"Tadesse","suffix":""},{"id":148794740,"identity":"f1810ef8-8440-48c8-83f4-4ab6f523d5e9","order_by":3,"name":"Archana Bachheti","email":"","orcid":"","institution":"Graphic Era University","correspondingAuthor":false,"prefix":"","firstName":"Archana","middleName":"","lastName":"Bachheti","suffix":""}],"badges":[],"createdAt":"2022-11-01 10:44:27","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-2225634/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-2225634/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":28682911,"identity":"149d3598-a062-44c2-8353-9594afb634a6","added_by":"auto","created_at":"2022-11-04 20:52:10","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":401718,"visible":true,"origin":"","legend":"\u003cp\u003eMap of the study area (pawe woreda, Metekel zone, western part of Ethiopia)\u003c/p\u003e","description":"","filename":"1.png","url":"https://assets-eu.researchsquare.com/files/rs-2225634/v1/c0eab47b169b82103ea41452.png"},{"id":28682917,"identity":"c0d82a19-72f5-47b1-b83c-da61dbdd7ec6","added_by":"auto","created_at":"2022-11-04 20:52:10","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":26483,"visible":true,"origin":"","legend":"\u003cp\u003eReaction mechanism for the synthesis of CNC/ZnO nanohybrids\u003c/p\u003e","description":"","filename":"2.png","url":"https://assets-eu.researchsquare.com/files/rs-2225634/v1/5c398af3bd78ab8090891063.png"},{"id":28682914,"identity":"be8b76af-68b1-49a7-a768-2589a48b1601","added_by":"auto","created_at":"2022-11-04 20:52:10","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":469006,"visible":true,"origin":"","legend":"\u003cp\u003eSEM image of ROA (a), COA (b), CNC (c), CNC/ZnO\u003csub\u003e1/2\u003c/sub\u003e (d), CNC/ZnO\u003csub\u003e3/4\u003c/sub\u003e (e) and CNC/ZnO\u003csub\u003e1\u003c/sub\u003e (f).\u003c/p\u003e","description":"","filename":"3.png","url":"https://assets-eu.researchsquare.com/files/rs-2225634/v1/cba2244c4380e1eb473f76b7.png"},{"id":28683886,"identity":"216f4931-d3b5-408a-a2ca-189e303f4f55","added_by":"auto","created_at":"2022-11-04 21:00:10","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":94833,"visible":true,"origin":"","legend":"\u003cp\u003eXRD image of CNC and CNC/ZnO samples\u003c/p\u003e","description":"","filename":"4.png","url":"https://assets-eu.researchsquare.com/files/rs-2225634/v1/fda6960e7ffbefdc80ce6e37.png"},{"id":28683887,"identity":"b84e8fa4-1128-46a8-9a08-ca9b20ba1c92","added_by":"auto","created_at":"2022-11-04 21:00:10","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":140640,"visible":true,"origin":"","legend":"\u003cp\u003ePeak of UV–Vis (left) and its band gap (right) of CNC and CNC/ZnO nanohybrids. Where (e): CNC; (d): CNC/ZnO\u003csub\u003e1/4\u003c/sub\u003e; (c); CNC/ZnO\u003csub\u003e1/2\u003c/sub\u003e;\u0026nbsp; (d); CNC/ZnO\u003csub\u003e3/4\u003c/sub\u003e; (a); CNC/ZnO\u003csub\u003e1\u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp;\u003c/sub\u003e\u003c/p\u003e","description":"","filename":"5.png","url":"https://assets-eu.researchsquare.com/files/rs-2225634/v1/f4ea221910fe95d3e28f90e1.png"},{"id":28684637,"identity":"947cc0e9-c66e-4c4f-bc90-9ff0ab710320","added_by":"auto","created_at":"2022-11-04 21:08:10","extension":"png","order_by":6,"title":"Figure 6","display":"","copyAsset":false,"role":"figure","size":28346,"visible":true,"origin":"","legend":"\u003cp\u003eCNC/ZnO and CNC FTIR spectra samples\u003c/p\u003e","description":"","filename":"6.png","url":"https://assets-eu.researchsquare.com/files/rs-2225634/v1/3a2296604edb94f95eb6bb98.png"},{"id":28682919,"identity":"802f1024-cb07-4888-8a2e-c6580bc1c7a4","added_by":"auto","created_at":"2022-11-04 20:52:10","extension":"png","order_by":7,"title":"Figure 7","display":"","copyAsset":false,"role":"figure","size":235005,"visible":true,"origin":"","legend":"\u003cp\u003eUV-Vis spectrum alterations in the MB using the CNC/ZnO nanohybrid at varied UV-Vis light exposure durations (0, 15, 30, 45, 60, and 75 min). (a) CNC/ZnO\u003csub\u003e1\u003c/sub\u003e, (b) CNC/Zno\u003csub\u003e3/4\u003c/sub\u003e, (c) CNC/ZnO½ and (d) six different samples\u0026nbsp;\u0026nbsp;\u003c/p\u003e","description":"","filename":"7.png","url":"https://assets-eu.researchsquare.com/files/rs-2225634/v1/0689a7d06a6906b98d8337f3.png"},{"id":28683885,"identity":"77610366-4cb4-4fa8-916b-c35bff683396","added_by":"auto","created_at":"2022-11-04 21:00:10","extension":"png","order_by":8,"title":"Figure 8","display":"","copyAsset":false,"role":"figure","size":86294,"visible":true,"origin":"","legend":"\u003cp\u003eDegradation rate (a) and degradation percentage (b) of ZnO/CNC nanohybrids.\u003c/p\u003e","description":"","filename":"8.png","url":"https://assets-eu.researchsquare.com/files/rs-2225634/v1/57602329b9a7e791f52d19fa.png"},{"id":28682922,"identity":"f5445d75-5e52-44d4-92f2-0e47425cb1dc","added_by":"auto","created_at":"2022-11-04 20:52:10","extension":"png","order_by":9,"title":"Figure 9","display":"","copyAsset":false,"role":"figure","size":140704,"visible":true,"origin":"","legend":"\u003cp\u003eCNC/ ZnO nanohybrids mechanism of photocatalytic activity\u003c/p\u003e","description":"","filename":"9.png","url":"https://assets-eu.researchsquare.com/files/rs-2225634/v1/dfd1c0cb878eb568bb082eec.png"},{"id":28682920,"identity":"5a7ec04d-918c-421e-9b79-6c4e53502e63","added_by":"auto","created_at":"2022-11-04 20:52:10","extension":"png","order_by":10,"title":"Figure 10","display":"","copyAsset":false,"role":"figure","size":14789,"visible":true,"origin":"","legend":"\u003cp\u003eIC50 value of CNC/ZnO\u003csub\u003e1\u003c/sub\u003e (A), CNC/ZnO\u003csub\u003e3/4\u003c/sub\u003e (B), CNC/ZnO\u003csub\u003e1/2\u003c/sub\u003e (C), CNC/ZnO\u003csub\u003e1/4 \u003c/sub\u003e(D), CNC (E) and AA (F).\u0026nbsp; \u003cem\u003eAll data were examined in triplicate, and the mean value \u003c/em\u003e± SD.\u003c/p\u003e","description":"","filename":"10.png","url":"https://assets-eu.researchsquare.com/files/rs-2225634/v1/1b1fbaa3ee429e113ae6265c.png"},{"id":28682923,"identity":"295955fd-082a-41d9-803c-ebb631709d1a","added_by":"auto","created_at":"2022-11-04 20:52:10","extension":"png","order_by":11,"title":"Figure 11","display":"","copyAsset":false,"role":"figure","size":814765,"visible":true,"origin":"","legend":"\u003cp\u003eThe zone of inhibition exhibited by CNC/ZnO against four bacteria species \u003cem\u003eKlebsiella pneumonia, Staphylococcus epidermidis Escherichia coli, and Staphylococcus aureus. (A)CNC/ZnO\u003c/em\u003e\u003csub\u003e\u003cem\u003e1/4\u003c/em\u003e\u003c/sub\u003e\u003cem\u003e, \u0026nbsp;(B) CNC/ZnO\u003c/em\u003e\u003csub\u003e\u003cem\u003e1/2\u003c/em\u003e\u003c/sub\u003e\u003cem\u003e, (C) CNC/ZnO\u003c/em\u003e\u003csub\u003e\u003cem\u003e3/4\u003c/em\u003e\u003c/sub\u003e\u003cem\u003e, and (D) CNC/ZnO\u003c/em\u003e\u003csub\u003e\u003cem\u003e1\u003c/em\u003e\u003c/sub\u003e\u003cem\u003e.\u003c/em\u003e\u003c/p\u003e","description":"","filename":"11.png","url":"https://assets-eu.researchsquare.com/files/rs-2225634/v1/1eb49f7714cb98bb7890d529.png"},{"id":32143973,"identity":"1664877c-bb3b-45bd-91ea-84053fbca710","added_by":"auto","created_at":"2023-01-28 02:44:32","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":2665712,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-2225634/v1/ba326ea3-501b-427a-9c49-5f6d49be085a.pdf"},{"id":28683884,"identity":"f7d0cb2d-cc03-4243-ae88-4d9fc239f55c","added_by":"auto","created_at":"2022-11-04 21:00:10","extension":"png","order_by":1,"title":"","display":"","copyAsset":false,"role":"supplement","size":236837,"visible":true,"origin":"","legend":"","description":"","filename":"GA.png","url":"https://assets-eu.researchsquare.com/files/rs-2225634/v1/c633a0ce4e7d0e71d748f0be.png"},{"id":28682912,"identity":"896e8d5a-4bf4-49d9-98ef-5c0dfbc847c5","added_by":"auto","created_at":"2022-11-04 20:52:10","extension":"png","order_by":2,"title":"","display":"","copyAsset":false,"role":"supplement","size":8867,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eScheme 1\u003c/strong\u003e:\u0026nbsp; Formation of ZnO mechanism in CNC\u003c/p\u003e","description":"","filename":"Scheme1.png","url":"https://assets-eu.researchsquare.com/files/rs-2225634/v1/4f739f0e9486a4035c97aeb0.png"}],"financialInterests":"No competing interests reported.","formattedTitle":"Synthesis, characterization, and application of nanohybrid formed by mixing carboxylated cellulose nanocrystal and zinc nitrate hexahydrate by precipitation method using Oxytenanthera abyssinica as raw material","fulltext":[{"header":"1.\tIntroduction ","content":"\u003cp\u003eCellulose is the most important material found in nature, which has been applied in various applications due to its low toxicity, biocompatibility, and biodegradability\u0026nbsp;(Kwok et al. \u0026nbsp;2017). It can be found in various substances, including tunicate, algae, fungi, natural fibers, wood, and bamboo\u0026nbsp;(Wang et al. 2021). Cellulose is the primary raw material for the preparation of cellulose nanocrystals (CNC)(Reid et al. 2017). \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u0026nbsp;For the past 20 years, academic research has focused on CNC due to its biodegradability, superior biocompatibility, high crystallinity, and excellent characteristics, such as large surface area, outstanding mechanical strength, and ease of chemical modification\u0026nbsp;(H\u0026aring;kansson et al. 2014; Thomas et al. 2018). Due to these remarkable characteristics, CNC has much potential in the fields of devices that store energy\u0026nbsp;(Chen et al. 2018; Kim et al. 2019), rheology modifiers\u0026nbsp;(Hubbe et al. 2017; Liu et al. 2017), reinforcing agents\u0026nbsp;(Clarkson et al. 2021; Zheng and Pilla, 2020), in the treatment of wastewater\u0026nbsp;(Abouzeid et al. 2018; Dong et al. 2021), biomedical components\u0026nbsp;(Du et al. 2019; Lin et al. 2019), and electrically flexible materials\u0026nbsp;(Miao et al. 2020; Zhao et al. 2021). However, its applicability is constrained by its poor UV permeability, poor moisture stability, and lack of antioxidant and antibacterial properties. As a result, limitations to the use of CNC in the fields of biomedicine and photocatalysis. The hydroxyl functional groups on the CNC surface, however, serve as reactive platforms that allow chemical modification for the addition of new functional groups to improve the material\u0026apos;s antibacterial, antioxidant and photocatalytic capabilities\u0026nbsp;(Tao et al. \u0026nbsp;2020). \u0026nbsp;\u003c/p\u003e\n\u003cp\u003eMetallic nanoparticles having favorable chemical and physical behavior are essential nanoscale materials successfully exploited in polymer functionalization\u0026nbsp;(Azizi et al. 2014). Inorganic nanoparticles, ZnO nanoparticles are relatively non-toxic, affordable, and have exceptional optical performance properties such as photocatalytic, electrical, antibacterial, and other capabilities\u0026nbsp;(Kołodziejczak-Radzimska and Jesionowski 2014). The utilization of ZnO in wastewater treatment has also recently received attention because of its capacity to degrade contaminants, such as organic dyes in water and heavy metals, removable during the purification of contaminated water\u0026nbsp;(Samadi et al. 2016; Sharma et al. 2019; Guan et al. 2019). Unfortunately, the ZnO NPs small size and high surface free energy quickly clump together. To overcome this drawback, scientists are highly interested in synthesizing ZnO nanoparticles based on another substance, functioning as a carrier to improve the dispersion of ZnO nanoparticles at the nanoscale level\u0026nbsp;(Tomczak et al. 2009). In this regard, combining CNC as template with ZnO nanoparticles has gained popularity, and studies have been conducted to modify and functionalize cellulose nanocrystals to prevent ZnO nanoparticle aggregation(Tomczak et al. 2009; Yang et al. 2016; Yu et al. 2015).\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eThere have been few publications on the formation of ZnO nanoparticles on cellulose substrates, even though research on cellulose-based nanocomposite materials is still ongoing. Most of the reported studies require complex synthesis procedures and time-consuming methods to prepare CNC. Since they mostly use inorganic acids (sulfuric acid, nitric acid, hydrochloric acid, etc) to hydrolysis cellulose, there are weak electrostatic interactions between Zn\u003csup\u003e2+\u003c/sup\u003e and OH-groups on CNC. Thus, in this study, CNC/ZnO nanohybrids were synthesized using carboxylated \u0026nbsp;CNC and N\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e6\u003c/sub\u003eZn.6H\u003csub\u003e2\u003c/sub\u003eO as starting materials for antibacterial, antioxidant, and photodegradation applications. We use Organic acid (citric acid) to hydrolyze cellulose derived from lowland Ethiopian bamboo (\u003cem\u003eOxytenathera abyssinica)\u003c/em\u003e as a nanocrystalline cellulose source abundantly in the western part of Ethiopia. \u0026nbsp;\u003c/p\u003e"},{"header":"2.\tExperimental ","content":"\u003cp\u003e\u003cstrong\u003e2.1 Materials and equipment \u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eWe employed analytical-grade chemicals in our investigation. In this investigation, the main chemicals used were CNC obtained from \u003cem\u003eOxytenanthera\u003cem\u003eabyssinica,\u003c/em\u003e\u003c/em\u003e Zinc nitrate (N\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e6\u003c/sub\u003eZn.6H\u003csub\u003e2\u003c/sub\u003eO) (99%,FARIDABAD-121005, INDIA), sulfuric acid (98%, India), citric acid anhydrous\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e(CHEMICALS UDYLOG-121001 (India), and sodium hydroxide (ALPHA CHEMIKA, India), sodium chloride (Maharashtra, India). All chemicals were acquired from the Charcos market center found in Addis Abeba, Ethiopia (Rankem India). The following instruments and equipment were frequently employed in these studies: sonicator (Intelligent Ultrasonic Processor), freeze dryer, \u003cem\u003ecentrifuges (\u003c/em\u003eMicrofuge Centurion Scientific PrO-Analytical C1015), Zeta sizer (Malvern Zeta Nano (ZE3600), Oven, Analytical balance for laboratories (Ceramic-technology weight sensor), dialysis tube, digital hot plate, Stirrer, XRD (SHIMADZU XRD-6000), SEM, TGA 55-TA Instruments and \u003cem\u003eiS50 FTIRS\u003c/em\u003e spectrometer, UV-Vis spectrophotometer Perkin Elmer UV\u0026ndash;Vis spectroscope (USA).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e2.2 The study area\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cem\u003eOxytenanthera abyssinica plant species\u0026nbsp;\u003c/em\u003ewere gathered from Pawe woreda, found in the Metekel zone, the western part of Ethiopia, as shown in Fig. 1. The area is situated between 36\u0026deg;20\u0026prime; and 36\u0026deg;32\u0026prime; longitude and 11\u0026deg;12\u0026prime; and 11\u0026deg;21\u0026prime; latitude. It is found at 1120 meters above sea level. The woreda has a hot, humid climate with temperatures ranging between 19.4 to 37.6\u0026deg;C, and receives 1586.32 mm of rain annually (Miruts, 2020). Of the total land of Pawe woreda, 30.6% is forest; among these, \u003cem\u003eOxytenanthera abyssinica\u003c/em\u003e is a botanical plant found in forests (Ambawu, 2019). A permition was obtained from the Pawe Woreda office of Agricultural and Rural Development to collect plant material based on support from Addis Abeba Science and Technology University.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e2.3 Sample collection\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cem\u003eOxytenanthera, abyssinica\u003c/em\u003e plants with an average age of three years, were randomly collected from the study area by TAPPI standards from 2002 (TAPPI, 2002). The plant material was gathered and delivered to Addis Abeba University for botanical identification. The identification was carried out by taxonomist Doctor Endale Adam and Mr. Wogayew using the Flora of Eritrea and Ethiopia\u0026apos;s taxonomic keys, as well as by comparison with the real specimens. This study has followed international, national, and institutional regulations in using plant components (IUCN, 1989). \u0026nbsp;\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e2.4 Preparation of cellulose nanocrystal \u0026nbsp; \u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cem\u003eOxytenanthera abyssinica\u003c/em\u003e (COA) cellulose hydrolyzed by citric acid anhydrous\u003cstrong\u003e\u0026nbsp;(\u003c/strong\u003eCAA) using Sulfuric acid (SA) as catalyst to produce the carboxylated CNC samples based on the methods used by \u0026nbsp;Xu et al. \u0026nbsp;(2017). Two grams of COA and (100 mL solution of 90 wt% CAA and 10% SA) was added to form solution. The solution was stirred with the Mixstab TEFAL Swing. The reactions were carried out in a spherical flask using an oil bath at 80 \u0026deg;C for 5 hours with a magnetic stirrer operating at 1000 rpm. After the hydrolysis reactions, hot distilled water (100 mL) was added to halt the process and avoid CAA crystallization. The subsequent step involved centrifuging the mixture for 15 minutes at 1000 rpm. The residue obtained after each centrifugation was rinsed with DI water three times. A dialysis tube was then used to dialyze the sediments until the solution\u0026apos;s pH and conductivity were constant with distilled water. Using a probe ultrasonicator, the suspension was sonicated for 15 minutes at 25 kHz after diluting to a consistency of around 1wt% to create a uniformly dispersed aqueous solution known as CNC.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e2.5 Preparation of ZnO/CNC nanohybrids \u0026nbsp; \u0026nbsp; \u0026nbsp;\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eCNC has a remarkable ability to absorb metallic cations since it has several hydroxyl groups in its structure. Electrostatic interactions between Zn\u003csup\u003e2+\u003c/sup\u003e and the oxygen atoms of hydroxyls allowed Zn\u003csup\u003e2+\u003c/sup\u003e to be absorbed during the initial phase of the process. After NaOH was added, Zn(OH)\u003csub\u003e2\u003c/sub\u003e was gradually produced. ZnO was produced under thermal conditions, as indicated by scheme1 and Fig. 2 (Azizi et al. 2014).\u003c/p\u003e\n\u003cp\u003eIn this research work, nanohybrids of CNC/ZnO were synthesized using a modified version of the technique utilized by \u0026nbsp;Yu et al. (2015). Different weights of 0.1 mol/L aqueous solutions of Zn(NO\u003csub\u003e3\u003c/sub\u003e)\u003csub\u003e2\u003c/sub\u003e. 6H\u003csub\u003e2\u003c/sub\u003eO was mixed with the carboxylated CNC produced in the above procedure in weight ratios of 0.25, 0.50, 0.75, and 1.00. These four samples were adjusted to a pH of 7 using 0.5 mol/L solutions of NaOH. To thoroughly precipitate Zn\u003csup\u003e2+\u003c/sup\u003e, the mixture was then vigorously agitated while being heated to 80 \u003csup\u003eo\u003c/sup\u003eC and adding 0.1 M NaOH solutions were drop by drop. The carboxylates (COO-) of CNCs and Zn\u003csup\u003e2+\u003c/sup\u003e were electrostatically attracted to one another, and Zn(OH)\u003csub\u003e2\u003c/sub\u003e precipitated. At 12,000 rpm, the mixture was centrifuged in DI water, at 10 \u003csup\u003eo\u003c/sup\u003eC, for 20 minutes to eliminate any byproducts and residual zinc species. Following this, the mixture was freeze-dried for 48 hours. To convert Zn(OH)\u003csub\u003e2\u0026nbsp;\u003c/sub\u003ecompound formed duet to the reaction of Zn\u003csup\u003e2+\u003c/sup\u003e and OH\u003csup\u003e-\u003c/sup\u003e (scheme 1) into ZnO, the samples were then dried for an hour at 120 \u003csup\u003eo\u003c/sup\u003eC. Based on CNC to Zn(NO\u003csub\u003e3\u003c/sub\u003e)\u003csub\u003e2\u003c/sub\u003e.6H\u003csub\u003e2\u003c/sub\u003eO weight ratio, the four samples are designated CNC/ZnO\u003csub\u003e1/4\u003c/sub\u003e, CNC/ZnO\u003csub\u003e1/2\u003c/sub\u003e, CNC/ZnO\u003csub\u003e3/4\u003c/sub\u003e, and CNC/ZnO\u003csub\u003e1\u003c/sub\u003e to represent CNC/ZnO (25, 50, 75 and 100%) sample respectively. \u0026nbsp; \u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e2.6 Characterization\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e2.6.1 Zeta potential test \u0026nbsp; \u0026nbsp;\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eUsing a Zeta sizer (Malvern Zeta Nano, ZE3600), the CNC and ZnO/CNC nanohybrids zeta potential values were determined in aqueous solution. An aqueous suspension (2.5 mg/mL) of the material, which was diluted to 0.01% was used to measure in triplicate at 25 \u003csup\u003eo\u003c/sup\u003eC. Table 1 displays the typical zeta potential values of CNC/ZnO nanohybrids. \u0026nbsp;\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e2.6.2 Carboxyl content analysis \u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cem\u003eConductometric titration\u003c/em\u003e is very important to determine the COOH group concentrationin the CNC/ZnO nanohybrids. 0.1g of dried sample and 10mL of 0.01M of NaCl solution were mixed with 100mL of DI water, and to produce a well-dispersed suspension, the produced solution was vigorously swirled. 0.1 M HCl was added to the mixture to reduce the pH to 2.5\u0026ndash;3.0. 0.015 M NaOH solutions were then added to the suspension at a rate of 0.1 ml per drop, bringing the pH up to 11. From conductivity-pH curves, the sample\u0026apos;s carboxyl group content was determined.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e2.6.3. UV\u0026ndash;Vis absorption \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp;\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eIn the range of 200 to 800 nm, UV\u0026ndash;Vis spectrophotometer (Perkin Elmer UV\u0026ndash;Vis spectroscope, USA), was utilized to determine the optical properties of MB suspension. Four CNC/ZnO hybrids samples, such as CNC/ZnO\u003csub\u003e1/4\u003c/sub\u003e, CNC/ZnO\u003csub\u003e1/2\u003c/sub\u003e, CNC/ZnO\u003csub\u003e3/4\u003c/sub\u003e, and CNC/ZnO\u003csub\u003e3/4\u003c/sub\u003e were characterized. \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp;\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cem\u003e\u003cstrong\u003e2.6.4 Scanning electron microscope\u003c/strong\u003e\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003eThe morphologies of the synthesized CNC/ZnO nanohybrids and CNC samples were evaluated by utilizing SEM (high vac. SED, PC-std, 15 kV) at 2.0 kV accelerating voltage at room temperature. Before SEM observation, the diluted suspension was added to dry on a silicon slice. \u0026nbsp;\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e2.6.5 Fourier transform infrared spectroscopy (FTIR)\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAn FT-IR spectrometer was used to collect the samples\u0026rsquo; FT-IR spectra. The spectra were recorded at wave numbers range of 4000-400 cm-1. The FTIR analysis was performed using the IS50 FTIR spectrometer. \u0026nbsp;\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e2.6.6 X-ray powder diffraction\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eUsing monochromatic Cu Ka radiation at k = 1.54056 A in the 2 range of 5-80 at a scan rate of 5 min-1, an X-ray powder diffractometer (SHIMADZU XRD-6000) was used to analyze the crystallite size and morphology CNC/ZnO nanohybrids and CNC. The crystallinity size was calculated using the Scherrer equation (equation 3) (Yu et al. 2012). The current and tension of the X-ray generator were 30 mA and 40 kV, respectively. \u0026nbsp; \u0026nbsp;\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e2.7 Photocatalytic activity\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAbsorption spectroscopy under UV irradiation was used to analyze the materials\u0026apos; photocatalytic activity by previously reported procedures \u0026nbsp;Fallah et al. (2011) and Zhai et al. (2014) depending on the photodegradation response of methylene blue (MB) dye. MB was exposed to high-intensity (365 nm, 115V-60 Hz, 2.5 A, 100 W) Lamp UV irradiation to examine CNC/ZnO nanohybrid photocatalytic properties. In 500 ml of deionized water, 10 ppm stock solution of MB was produced, and then 2 mg of different samples was added to 60 ml of 10ppm dye solution. The solution was stirred with a magnetic stirrer for 15 minutes in the dark to reach the system\u0026apos;s adsorption equilibrium before irradiation. The mixture was exposed to UV irradiation for 15 min time intervals (15, 30, 45, and 75). The testing samples (CNC, CNC/ZnO\u003csub\u003e1\u003c/sub\u003e, CNC/ZnO\u003csub\u003e3/4\u003c/sub\u003e, CNC/ZnO\u003csub\u003e1/2\u003c/sub\u003e, and CNC/ZnO\u003csub\u003e1/4\u003c/sub\u003e) were removed from the colloidal mixture, and cleaned supernatant was obtained by centrifuging for 15 minutes at 5,000 rpm. The Perkin Elmer UV-Vis spectroscope (USA) was then utilized to determine the absorbance spectra of the supernatant from 350 to 850 nm wavelength. The absorbance value at 660 nm was used to calculate the dye concentration during the degradation process. To calculate the percentage of MB degradation, the equation below was used.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp;Degradation rate \u0026nbsp;= \u0026nbsp; \u0026nbsp;\u0026hellip;\u0026hellip;\u0026hellip;\u0026hellip;\u0026hellip;\u0026hellip;\u0026hellip;. (1)\u003c/p\u003e\n\u003cp\u003e\u0026nbsp; \u0026nbsp;Where: C\u003csub\u003et\u0026nbsp;\u003c/sub\u003eand C\u003csub\u003e0\u003c/sub\u003e are the concentrations of the MB after and before UV radiation, respectively. \u0026nbsp; \u0026nbsp; \u0026nbsp;\u003c/p\u003e\n\u003ch3\u003e2.8 Antioxidant activities\u0026nbsp;\u003c/h3\u003e\n\u003cp\u003eThe DPPH radical scavenging assay described by \u0026nbsp;Blois (1958) \u0026nbsp;and \u0026nbsp;Desmarchelier et al. (1997) was used to examine the antioxidant potential of samples to scavenge free radicals. The color change of a methanolic solution of 2, 2-diphenyl-1-picrylhydrazyl (DPPH) was utilized to assess the potential scavenging activities of free radicals of the CNC/ZnO samples. When DPPH is dissolved in methanol, it generates a violet or purple color, with antioxidants\u0026apos; actions cause to fade to various shades of yellow color. In order to investigate the antioxidant properties of the prepared sample,\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eAscorbic acid was utilized as a standard to measure the percentage of DPPH radical scavenging activity using equation 2. A 0.1 mM DPPH solution in methanol was initially dissolved. Subsequently, 2.4 mL of this solution was added to 1.6 mL of CNC/ZnO nanohybrid sample dissolved in methanol at various concentrations (25 - 125 g/mL). After fully vortexing the mixed solution, the reaction mixture was kept at room temperature for 30 minutes. At 517 nm, the mixture\u0026apos;s absorbance was determined spectrophotometrically. \u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp;% DPPH radical scavenging activities = \u0026hellip;\u0026hellip;\u0026hellip;\u0026hellip;\u0026hellip;\u0026hellip;(2)\u003c/p\u003e\n\u003cp\u003eWhere: \u0026nbsp; A\u003csub\u003e1\u003c/sub\u003eand A\u003csub\u003e0\u0026nbsp;\u003c/sub\u003eare UV absorbance of samples and control, respectively\u003c/p\u003e\n\u003ch3\u003e2.9 Antibacterial susceptibility testing of sample \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp;\u003c/h3\u003e\n\u003cp\u003eThe in vitro bactericidal activity of CNC/ZnO\u003csub\u003e1\u003c/sub\u003e, CNC/ZnO\u003csub\u003e3/4\u003c/sub\u003e, CNC/ZnO\u003csub\u003e1/2\u003c/sub\u003e, and CNC/ZnO\u003csub\u003e1/4\u0026nbsp;\u003c/sub\u003ewas investigated using the disc diffusion method. The dry samples were first dissolved in sterilized distilled water (5 mL) to achieve the necessary test concentration of 0.25, 0.50, 0.75, and 1.00 mg/ml. 5 mm-diameter discs of Whatman\u0026apos;s No. 1 filter paper were produced using a paper borer. These discs were exposed for 24 hours to each test concentration. The discs were taken out and dried in an aseptic condition. \u0026nbsp; \u0026nbsp;\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eA pure culture of two gram -ve bacteria species such as \u003cem\u003eKlebsiella pneumonia and Escherichia coli\u003c/em\u003e, and two gram +ve photogene including \u0026nbsp;\u003cem\u003eStaphylococcus epidermidis and Staphylococcus aureus\u003c/em\u003e were incubated for 72 hours to make the bacterial solution. The suspension was made using sterilized distilled water. Using a spectrophotometer, the suspension\u0026apos;s optical density was adjusted to 0.132 at 600 nm. This is equivalent to 0.5 McFarland turbidity standards. At this turbidity level, 1.5 \u0026times; 108 CFU/mL of bacteria is present. The Muller-Hinton Agar medium was aseptically inoculated with around 0.5 mL of the bacterial suspension, and the spreader was used to disseminate it evenly. Sensitive discs of ciprofloxacin 30 \u0026micro;g/mL concentration were used as standard controls. Within 15 minutes, the dried discs were applied to the inoculated Petri dishes. All the Petri plates were incubated at 37\u0026ordm;C. Each test concentration was examined three times during the antibacterial susceptibility testing process. The antibacterial activity of extracts was assessed using the zone of inhibition\u0026apos;s diameter. Using a transparent ruler or meter, the inhibitory zone was seen and measured in millimeters. \u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e2.10 Statically analysis\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eOrigin 8 software was used to analyze the results variance (one-way ANOVA). All measurements were done three times (n=3), and the results are the average of three repetitions with standard deviations (SD). A confidence limit of P value less than or equal to 0.05 was used to determine significance.\u0026nbsp;\u003c/p\u003e"},{"header":"3.\tResult And Discussion ","content":"\u003cp\u003e\u003cstrong\u003e3.1 Size distribution, carboxyl content, and zeta potential\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe DLS experiment was performed on a CNC/ZnO suspension made from CNC. The resulting size distribution is shown in Table 1. It was found that the CNC sample had the shortest average particle size (94.2 - 259 nm) than CNC/ZnO\u003csub\u003e1/4\u0026nbsp;\u003c/sub\u003e(103.4 - 281 nm), CNC/ZnO\u003csub\u003e1/2,\u003c/sub\u003e (122.4- 295.3 nm), CNC/ZnO\u003csub\u003e3/4\u0026nbsp;\u003c/sub\u003e(128.4-301.4 nm) and CNC/ZnO\u003csub\u003e1\u003c/sub\u003e (119 to 341.2 nm) samples. This finding indicates that hydrolysis of COA by CAA is more likely to produce smaller size cellulose nanocrystals. However, the size of the samples increased as ZnO nanoparticles were added to CNC. CNC/ZnO\u003csub\u003e1\u003c/sub\u003e samples displayed the biggest size compared to the other samples. Since more ZnO nanoparticles grow on the CNC surface due to more Zn\u003csup\u003e2+\u003c/sup\u003e being coupled with CNC. As shown in Table 1, the size of CNC/ZnO samples slightly increased in the order of CNC, CNC/ZnO\u003csub\u003e1/4\u003c/sub\u003e, CNC/ZnO\u003csub\u003e1/2\u003c/sub\u003e, CNC/ZnO\u003csub\u003e3/4\u003c/sub\u003e and CNC/ZnO\u003csub\u003e1\u003c/sub\u003e with the size distribution of 94.2 - 259 nm, 103.4 - 281 nm, 122.4- 295.3 nm, 128.4- 301.4 nm, and 1119 to 341.2 nm respectively.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eThe results of the carboxyl group content of the CNC/ZnO nanohybrid obtained based on the \u003cem\u003econductometric titration\u0026nbsp;\u003c/em\u003emethod are shown in Table 1. The highest concentration was found for CNC samples (0.75\u0026plusmn; 0.08mmol/g) due to more carboxyl groups. The carboxyl content of the CNC/ZnO\u003csub\u003e1\u003c/sub\u003e showed the smallest amount (0.15\u0026plusmn; 0.24) than CNC/ZnO\u003csub\u003e3/4\u003c/sub\u003e(0.37\u0026plusmn; 1.01), CNC/ZnO\u003csub\u003e1/2\u003c/sub\u003e (0.58\u0026plusmn;0.78) and CNC/ZnO\u003csub\u003e1/4\u0026nbsp;\u003c/sub\u003e(0.71\u0026plusmn; 2.01). This is due to more hydroxyl groups in CNC enclosed by ZnO nanoparticles. When the concentration of Zn\u003csup\u003e2+\u003c/sup\u003e increased, the reaction solution contained many Zn\u003csup\u003e2+\u003c/sup\u003e ions and reacted with more hydroxyl groups of the dissolved CNC, this characteristic decreased the carboxyl content.\u003c/p\u003e\n\u003cp\u003eThe average value of zeta potential acquired for CNC, CNC/ZnO\u003csub\u003e1/4\u003c/sub\u003e, CNC/ZnO\u003csub\u003e1/2\u003c/sub\u003e, CNC/ZnO\u003csub\u003e3/4\u003c/sub\u003e, and CNC/ZnO\u003csub\u003e1\u003c/sub\u003e was -33mV, -13.7mV,-11.7mV, -10.4mV and -9.25mV, respectively (Table 1). All CNC/ZnO samples exhibited lower zeta potential compared to CNC. This is due to the carboxyl group found in CNC participating in the ZnO nanoparticles preparation system. During the preparation of CNC via esterification reaction, negatively charged nanoparticles are produced due to carboxyl groups on their surface. This affects the tendency of the zeta potential value of the CNC sample (Yu et al. 2016). CNC/ZnO\u003csub\u003e1\u003c/sub\u003e has the lowest absolute value of zeta potential (-9.25 Mv), followed by CNC/ZnO\u003csub\u003e3/4\u003c/sub\u003e with a value of -10.4 Mv. However, CNC/ZnO\u003csub\u003e1/4\u003c/sub\u003e has the highest value (-13.7 Mv) among the four nanohybrid samples. This is because the zeta potential of the CNC is consistent with the carboxyl content of CNC samples (Table 1). As the content of COOH increases, the absolute value of zeta potential also increases(Yu et al. 2016). CNC had the highest absolute zeta potential (-33 mV), indicating the highest repelling force between CNC samples driven by the most considerable carboxyl content. \u0026nbsp;\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eTable 1 \u0026nbsp;\u003c/strong\u003ezeta potential, carboxyl content, and size distribution of CNC/ZnO nanohybrids\u0026nbsp;\u003c/p\u003e\n\u003ctable border=\"1\" cellpadding=\"0\" cellspacing=\"0\" width=\"607\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"26.85337726523888%\"\u003e\n \u003cp\u003eSamples\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"22.73476112026359%\"\u003e\n \u003cp\u003eZeta\u003c/p\u003e\n \u003cp\u003epotential\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"23.72322899505766%\"\u003e\n \u003cp\u003eCarboxyl\u003c/p\u003e\n \u003cp\u003econtent\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"26.68863261943987%\"\u003e\n \u003cp\u003eSize (d.nm) from DLS data\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"26.85337726523888%\"\u003e\n \u003cp\u003eCNC\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"22.73476112026359%\"\u003e\n \u003cp\u003e-33 \u0026nbsp;mV\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"23.72322899505766%\"\u003e\n \u003cp\u003e0.75\u0026plusmn; 0.19\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"26.68863261943987%\"\u003e\n \u003cp\u003e94.2 - 259 nm\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"26.85337726523888%\"\u003e\n \u003cp\u003eCNC/ZnO\u003csub\u003e1/4\u003c/sub\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"22.73476112026359%\"\u003e\n \u003cp\u003e-13.7\u0026nbsp;mV\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"23.72322899505766%\"\u003e\n \u003cp\u003e0.71\u0026plusmn; 2.01\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"26.68863261943987%\"\u003e\n \u003cp\u003e103.4 - 281 nm\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"26.85337726523888%\"\u003e\n \u003cp\u003eCNC/ZnO\u003csub\u003e1/2\u003c/sub\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"22.73476112026359%\"\u003e\n \u003cp\u003e-11.7 \u0026nbsp;mV\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"23.72322899505766%\"\u003e\n \u003cp\u003e0.58\u0026plusmn; 0.78\u003csup\u003ec\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"26.68863261943987%\"\u003e\n \u003cp\u003e122.4- 295.3 nm\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"26.85337726523888%\"\u003e\n \u003cp\u003eCNC/ZnO\u003csub\u003e3/4\u003c/sub\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"22.73476112026359%\"\u003e\n \u003cp\u003e-10.4\u0026nbsp;mV\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"23.72322899505766%\"\u003e\n \u003cp\u003e0.37\u0026plusmn; 1.01\u003csup\u003ed\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"26.68863261943987%\"\u003e\n \u003cp\u003e128.4- 301.4 nm\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"26.85337726523888%\"\u003e\n \u003cp\u003eCNC/ZnO\u003csub\u003e1\u003c/sub\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"22.73476112026359%\"\u003e\n \u003cp\u003e-9.25\u0026nbsp;mV\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"23.72322899505766%\"\u003e\n \u003cp\u003e0.15\u0026plusmn; 0.24\u003csup\u003ee\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"26.68863261943987%\"\u003e\n \u003cp\u003e1119 to 341.2 nm\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e\u003cem\u003eAll data were examined in triplicate, and the mean value\u0026nbsp;\u003c/em\u003e\u0026plusmn; SD \u003cem\u003ewas taken and written in the table. The identical alphabetical letter indicates that there are no statically significantly different (P\u0026gt;0.05) between values in the same column.\u0026nbsp;\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e3.2 Scanning Electron Microscope (SEM) Analysis \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eFig. 3 displays ROA, COA, CNC, and CNC/ZnO samples in SEM images. The SEM image shows the differences in the fiber surfaces between ROA and COA by observing images after and before the bleaching process. The image confirmed that the surface of COA fibers is smoother and has less solid aggregate than ROA fiber. Additionally, the COA exhibit decreased aggregation, suggesting that the bleaching procedure was successful in removing a sizable portion of the amorphous mass from the fiber surfaces, such as low molar mass polysaccharides, impurities, and lignin reported previously by \u0026nbsp;C\u0026eacute;sar et al. (2015); Khan et al. (2009) and \u0026nbsp;G\u0026uuml;ltekin (2016). ROA showed a larger size (23.0 to 8.34 \u0026micro;m) than COA (18.05 to 4.01\u0026micro;m) samples. SEM images of ZnO/CNC and CNC show that the morphology of CNC is similar to a rod-shaped size with a smaller size (31 to 259 nm) due to the acid hydrolysis influence of chemicals in the synthesis process. Following the precipitation of CNC and Zn\u003csup\u003e2+\u003c/sup\u003e ions in the CNC/ZnO\u003csub\u003e1/2\u003c/sub\u003e sample, ZnO nanoparticles with a mean diameter of 164.18 nm and size distribution of 94\u0026ndash;259 nm were formed on the surface of CNC. The average diameter of ZnO nanoparticles increased to 183.5 nm in a CNC/ZnO\u003csub\u003e1\u003c/sub\u003e sample with a size range of 128 to 351 nm due to an increase in Zn\u003csup\u003e2+\u003c/sup\u003e ion concentration. As more Zn\u003csup\u003e2+\u003c/sup\u003e ions become immobilized on the CNC surface, causes the number of ZnO particles in CNC increases. \u0026nbsp;\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e3.3 X-ray powder diffraction (\u003cem\u003eXRD\u003c/em\u003e) \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp;\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eFig. 4 displays the CNC and CNC/ZnO nanohybrid\u0026apos;s XRD image. The cellulose I characteristic peaks are visible in the CNC\u0026apos;s XRD pattern at 2\u0026theta; = 15.68\u0026deg;, 22.58\u0026deg;, and 34.54\u0026deg; (French AD 2014). In addition to the cellulose-specific peaks, The ZnO/CNC samples also show additional peaks at 69.42\u0026deg;, 67.5\u0026deg;, 62.54\u0026deg;, 56.76\u0026deg;, 47.68\u0026deg;, 36.38\u0026deg;, 34.52\u0026deg;, and 31.98\u0026deg;, which are assigned to the values (201), (112), (103), (110), (102), (101), (002), and (100), respectively (Sirvio\u0026uml; JA et al. 2014; Ul-Islam et al. 2014). This is an indication of the formation of nanohybrids. The crystal structure of the \u0026nbsp;ZnO is revealed by the prominent intensity diffraction peaks in the XRD scheme (Sharma et al. 2019; Guan et al. 2019). Fig. 4 shows two-phase structures that show CNC/ZnO (#) and CNC (*) were observed. This showing using CNC, ZnO nanohybrid has been synthesized effectively. The low-intensity peaks of CNC/ZnO nanohybrids compared to the XRD peak of pure ZnO nanoparticles showed the deposition of ZnO NPs on the CNC surface. The findings further demonstrate that the existence of ZnO crystals does not affect the cellulose crystal structure. Three CNC/ZnO nanohybrid samples have similar XRD patterns. This demonstrated the efficient one-step ZnO synthesis on CNC in a successful manner. These profiles indicated that the presence of well-crystalline ZnO has not changed the crystal structure of the cellulose matrix. The Figure further demonstrated that, with rising Zn\u003csup\u003e2+\u003c/sup\u003e ion concentrations, ZnO peaks get broader and more powerful over time. This suggests that the CNC/ZnO nanohybrids\u0026apos; crystal size and crystallinity have increased. Using debye-Scherrer technology, the crystal size (D) of the CNC/ZnO and CNC, structures were determined from the XRD data using equation (3).\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cimg src=\"data:image/png;base64,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\" height=\"59\" width=\"313\"\u003e\u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp;\u003c/p\u003e\n\u003cp\u003eWhere: \u0026beta; is the integral breadth of the maximum complete width (FWHM), \u0026lambda; is X-ray radiation\u0026apos;s wavelength (k=0.94), D\u003csub\u003ehkl\u003c/sub\u003e is the size of a crystallite in nanometers as viewed from the crystal\u0026apos;s(hkl) plane, (\u0026pi;/180) is the correction factor in changing \u0026beta; into radians, and \u0026theta; is the scattering angle,\u003c/p\u003e\n\u003cp\u003eThe predicted size of the CNC hybrid\u0026apos;s ZnO crystal was 11.5nm, 10.7nm, and 9.8nm for CNC/ZnO\u003csub\u003e1\u003c/sub\u003e, CNC/ZnO\u003csub\u003e3/4,\u003c/sub\u003e and CNC/ZnO\u003csub\u003e1/2\u003c/sub\u003e, respectively. The three samples\u0026apos; estimated crystallite sizes match those in Fig. 4 XRD patterns because the purer ZnO is typically associated with larger crystal sizes, which are typically associated with sharper intensity peaks., In contrast, the CNC/ZnO spectrum\u0026apos;s smaller and wider peaks are connected to a smaller crystal size (Mumalo-Djokic et al. 2008; Taunk et al., 2015). These intensity peaks and crystal planes showed that ZnO nanoparticles effectively formed on the CNC surface.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e3.4 Ultraviolet-visible (UV-Vis)\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe optical properties of CNC/ZnO nanohybrids with various Zn\u003csup\u003e2+\u003c/sup\u003e concentrations were examined by utilizing a UV-Vis spectrophotometer. Fig. 5 shows the UV-Vis absorption peak of the CNC and CNC/ZnO nanohybrids. It was found that the CNC\u0026apos;s spectra lacked any noticeable peaks between 300 and 700 nm. However, the UV\u0026ndash;Vis peak showed a strong peak before 400 nm for all ZnO/CNC samples. The absorption bands for the CNC/ZnO\u003csub\u003e1/4\u003c/sub\u003e, CNC/ZnO\u003csub\u003e1/2\u003c/sub\u003e, CNC/ZnO\u003csub\u003e3/4\u003c/sub\u003e, and CNC/ZnO\u003csub\u003e1\u003c/sub\u003e samples were 363, 366, 372, and 376 nm, respectively. ZnO\u0026apos;s basic band gap absorption, which happens when an electron transitions from the valence band to the conduction band (O2p \u0026rarr; Zn3d), is responsible for these peaks (Zak et al. 2011). This shows that ZnO nanoparticles have formed on the surface of CNC. It is intriguing to observe that the larger ZnO caused the absorption band to move toward the red (redshift). This suggests that when the Zn\u003csup\u003e2+\u003c/sup\u003e ion concentration increases, more significant ZnO nanoparticles might be produced. According to the plot of Tauc shown in Fig. 5(b), the band gaps for the samples CNC/ZnO\u003csub\u003e1/4\u003c/sub\u003e, CNC/ZnO\u003csub\u003e1/2\u003c/sub\u003e, CNC/ZnO\u003csub\u003e3/4\u003c/sub\u003e, and CNC/ZnO\u003csub\u003e1\u003c/sub\u003e are 3.32, 3.29, 3.21, and 3.07 eV, respectively. The sample band gaps estimated from (\u0026alpha;hʋ)2 versus (hʋ) plot match with the mode of Kubelka-Munk (Yu et al. 2008). \u0026nbsp;\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e3.5 Fourier transform infrared \u0026nbsp;\u003c/strong\u003e\u003cstrong\u003espectroscopy (FTIR)\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe identification of functional group and bond structure determination of the CNC/ZnO nanohybrids samples was examined by FTIR instrument in the peak range of 400 and 4000 cm-1 (Fig. 6). Peaks at 3315-3340 cm-1 in the CNC/ZnO nanohybrids and CNC spectra were attributed to the O-H stretching mode (Azizi et al. \u0026nbsp;2013). After adding ZnO to cellulose, the strength of the O-H stretching vibrations weakened for CNC/ZnO\u003csub\u003e3/4\u003c/sub\u003e and CNC/ZnO\u003csub\u003e1,\u0026nbsp;\u003c/sub\u003eas shown in Fig. 6. This suggests oxygen atoms participated in the bonding interaction with ZnO and weakened the O-H bond. The peak at 1435 cm-1 was assigned to the CH2 vibration and taken as the crystallization band for each cellulose material, while sharp peak was indicated to C-O stretching for the CNC and CNC/ZnO samples. Its intensity decreases as the concentration of ZnO increases. According to \u0026nbsp;Lu and Hsieh (2010), the peak at 1,650 cm\u003csup\u003e-1\u003c/sup\u003e is because of the C-O-C bond stretching of glucose and pyranose ring skeletal vibration, but the peak at roughly 1,065 cm\u003csup\u003e-1\u003c/sup\u003e is caused by the O-H bending of a water molecule (Cherian et al. \u0026nbsp;2008). The band intensity (1.721cm\u003csup\u003e-1\u003c/sup\u003e) for the C=O stretch decreased in intensity compared to the CNC peak intensity. This resulted from the potent interaction between the COOH groups on the CNC surface and the ZnO NPs.\u003c/p\u003e\n\u003cp\u003eCompared to CNC, more absorption peaks at 600\u0026ndash;400 cm were found in ZnO/CNC nanohybrids, and these peaks were linked to Zn\u0026ndash;O stretching modes (Azizi et al. \u0026nbsp; 2013; Wei et al. 2013). The Zn-O peaks of ZnO/CNC\u003csub\u003e1\u003c/sub\u003e, ZnO/CNC\u003csub\u003e3/2\u003c/sub\u003e, and ZnO/CNC\u003csub\u003e1/2\u003c/sub\u003e were located at 435, 432, and 412 cm-1, respectively. This verifying ZnO was successfully synthesized on the CNC template (Azizi et al. \u0026nbsp; 2013; Zhang et al. 2013). The lack of a peak in the CNC sample between 400 and 450 cm-1 indicates that ZnO is not present in the sample. With increasing Zn\u003csup\u003e2+\u003c/sup\u003e ion concentration, a little shift of the Zn-O stretching bands to higher wavenumbers was observed because of the lattice structure of the ZnO nanoparticles. The absorption peak at 2900 cm\u003csup\u003e-1\u003c/sup\u003e, is related to the C-H vibration of sp3-hybridized carbon. This peak vanished when the CNC/ZnO nanohybrid was synthesized (Oyewo et al. 2019). This peak\u0026apos;s intensity also decreased with ZnO loading increase (Fig. 6). The decrease in intensity of the peak indicates that ZnO is present or loaded to the CNC lattice. A similar observation was made in the work of \u0026nbsp;Ali et al. (2016) and Keshk and Hamdy (2019) using nanocomposites made of cellulose and ZnO. \u0026nbsp;\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e3.6 Application of CNC/ZnO nanohybrids \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e3.6.1 Photocatalytic activity \u0026nbsp; \u0026nbsp; \u0026nbsp;\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eBy using solid-phase photodegradation MB dye, the photocatalytic activity of four different samples, including CNC/ZnO\u003csub\u003e1\u003c/sub\u003e, CNC/ZnO\u003csub\u003e3/4\u003c/sub\u003e, CNC/ZnO\u003csub\u003e1/2\u003c/sub\u003e, and CNC/ZnO\u003csub\u003e1/4\u0026nbsp;\u003c/sub\u003e(Fig. 7), was investigated. The degradation of MB caused by exposure to UV radiation was used to determine the effectiveness of CNC/ZnO samples as photo-catalyst activities.\u0026nbsp;The adsorption-desorption studies were carried out in complete darkness for 5 minutes, and the absorption spectra after this adsorption-desorption step are reported as \u0026quot;0 min\u0026quot;.\u0026nbsp;At various time intervals and under the identical circumstances, the photocatalytic activity of CNC was also assessed for comparison.\u003c/p\u003e\n\u003cp\u003eTo determine how much UV light could potentially degrade MB, a blank test was run to see how much MB would degrade without a photocatalyst. \u0026nbsp;\u003c/p\u003e\n\u003cp\u003eFig. 7a, 7b, and 7c illustrate the photocatalytic capability of CNC/ZnO nanohybrids to degrade MBs when exposed to UV light in a 75-minute irradiation time. The result showed that in samples containing CNC solely, no notable changes in the UV absorption band of MB were seen after 75 minutes of UV exposure. Fig. 7d shows the MB degradation when it reacted with different CNC/ZnO samples. The degradation increase in the order of CNC/ZnO\u003csub\u003e1\u003c/sub\u003e, CNC/ZnO\u003csub\u003e3/4\u003c/sub\u003e, CNC/ZnO\u003csub\u003e1/2\u003c/sub\u003e, and CNC/ZnO\u003csub\u003e1/4\u003c/sub\u003e. The Fig. also shows that there is no significant difference in absorbance between CNC and MB; this showed that CNC has the lowest capacity to reduce the absorbance of MB. Fig. 7d also shows the MB\u0026apos;s absorbance reduction due to the addition of CNC and CNC/ZnO samples. Based on the Fig.s, the absorption peak of MB (2.23) reduced to 0.79, 0.93, 1.07, and 1.38 for CNC/ZnO\u003csub\u003e1\u003c/sub\u003e, CNC/ZnO\u003csub\u003e3/4\u003c/sub\u003e, CNC/ZnO\u003csub\u003e1/2\u003c/sub\u003e, and CNC/ZnO\u003csub\u003e1/4\u003c/sub\u003e respectively. Less MB degradation was evident with higher UV absorption values. The lowest absorption peak (highest degradation) is shown in CNC/ZnO\u003csub\u003e1\u003c/sub\u003e and the most significant (lowest degradation) is shown in CNC/ZnO\u003csub\u003e1/4\u003c/sub\u003e. This is related to the concentration of ZnO concentration present in the sample. As the amount of ZnO increases, the chance of e\u003csup\u003e-\u0026nbsp;\u003c/sup\u003eand h\u003csup\u003e+\u003c/sup\u003e reacting with O\u003csub\u003e2\u003c/sub\u003e and H\u003csub\u003e2\u003c/sub\u003eO to generate free radical(OH\u003csup\u003e-\u003c/sup\u003e) and O\u003csub\u003e2\u003c/sub\u003e\u003csup\u003e-\u003c/sup\u003e also increases (Fig. 9); this might take part in the direct oxidative breakdown of MB dye \u0026nbsp;(Qi et al. 2017; Lefatshe et al. 2017; \u0026nbsp;Balcha et al. 2016). \u0026nbsp;\u003c/p\u003e\n\u003cp\u003eAs seen in Fig. 8, the samples\u0026apos; exposure period to UV light impacts MB deterioration. To measure the effect of MB degradation with time, we measured the UV absorbance of the samples every 15-minute interval for 75 minutes. The result showed that the samples\u0026apos; absorbance decreased when the reaction time increased\u0026mdash;however, the rate of degradation over time increased. As shown in Fig. 8, CNC/ZnO\u003csub\u003e1\u003c/sub\u003e has the highest degradation rate, while CNC/ZnO\u003csub\u003e1/4\u003c/sub\u003e has the lowest degradation rate every 15, 30, 45, 60, and 75 minutes of exposure to UV irradiation. \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp;\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eFig. 8b demonstrate that, after 75 min of UV irradiation, ungraded MB for CNC/ZnO\u003csub\u003e1\u003c/sub\u003e, CNC/ZnO\u003csub\u003e3/4\u003c/sub\u003e, CNC/ZnO\u003csub\u003e1/2\u003c/sub\u003e, CNC/ZnO\u003csub\u003e1/4\u003c/sub\u003e and CNC samples were 8.48, 19.65, 36.42, 45.88 and 83.48% respectively. Since ZnO was absent from the CNC sample, the 75-minute UV exposure exhibited no appreciable impact on the MB UV absorption band. After a 75-minute reaction, the lowest percentage of MB degradation (16.52%) was found in CNC, which had a lower degradation rate than CNC/ZnO\u003csub\u003e1\u003c/sub\u003e (91.52%), CNC/ZnO\u003csub\u003e3/4\u003c/sub\u003e (80.348%), CNC/ZnO\u003csub\u003e1/2\u0026nbsp;\u003c/sub\u003e(63.58%), and CNC/ZnO\u003csub\u003e1/4\u0026nbsp;\u003c/sub\u003e(54.12%) (Fig. 8a). According to the Figure after being exposed to UV radiation for 75 minutes in CNC/ZnO\u003csub\u003e1\u003c/sub\u003e nanohybrid, roughly 91.52% of the MB dye rapidly decomposed. This finding suggests that ZnO/CNC\u003csub\u003e1\u003c/sub\u003e nanohybrids have strong electrical interactions with ZnO nanoparticles that are well dispersed on the CNC surface. These characteristics possessed the sample to have higher photocatalytic activity than other samples. This photocatalytic performance in the present study was more effective than the photocatalytic activity (less than 90%) of CNC/ZnO nanohybrids made by \u0026nbsp;Nang An et al. (2020) in 75 minutes of UV exposure time and comparable photocatalytic activities (about 90%) have been seen in the work of \u0026nbsp;Yu et al. (2015) in 75 minute time.\u003c/p\u003e\n\u003cp\u003eFig. 9 illustrates a potential mechanism for the CNC/ZnO nanohybrids photocatalytic activity according to the above results. ZnO can make photogenerated electron-hole pairs by absorbing UV light. The resulting photogenerated hole (h+) and electron (e-) could go to the ZnO nanoparticles\u0026apos; surface, interacting with both H\u003csub\u003e2\u003c/sub\u003eO and O\u003csub\u003e2\u003c/sub\u003ethat have been absorbed on the surface of ZnO to produce O\u003csub\u003e2\u003c/sub\u003e- and OH, which could take part in the direct oxidation that leads to dye degradation (Huang et al. 2014; \u0026nbsp;Zhai et al. 2014). \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e3.6.2 Determination of antioxidant activity Using the DPPH \u0026nbsp;radical scavenging method\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAs a result of its sensitivity to detect active substances at low doses, the 2,2-Diphenyl-1-picrylhydrazyl (DPPH) assay is frequently employed to test for antioxidant activity (Tettey and Shin 2019). Since DPPH is a nitrogen-centered free radical, any substance significantly reducing DPPH levels may also lower the amount of other reactive nitrogen species (Tettey and Shin \u0026nbsp;2019). \u0026nbsp;Our findings show that the CNC/ZnO nanohybrid could dose-dependently quench DPPH free radicals at 25, 50, 75, 100, and 125 g/ml concentrations. According to the data in Table 2, CNC/ZnO\u003csub\u003e1\u003c/sub\u003e had the highest percentage inhibition value (25 g/mL, 11.09% 1.21; 50 g/mL, 21.43% 2.11; 75 g/mL, 32.07% 0.74; 100 g/mL, 42.51% 0.62; and 125 g/mL, 53.15% 1.03) than the other samples. This demonstrated that it had higher free radical scavenging activity levels than the other samples. CNC/ZnO\u003csub\u003e1\u003c/sub\u003e has not shown a significant (p percentage inhibition compared to CNC/ZnO\u003csub\u003e3/4\u003c/sub\u003e. However, there is a significant (p\u0026nbsp;percentage inhibition value in the rest of the samples. CNC\u0026apos;s value is the smallest compared to CNC/ZnO\u003csub\u003e1\u003c/sub\u003e, CNC/ZnO\u003csub\u003e3/4\u003c/sub\u003e, CNC/ZnO\u003csub\u003e1/2,\u003c/sub\u003e and CNC/ZnO\u003csub\u003e1/4\u003c/sub\u003e samples. This is an indication that CNC has the smallest antioxidant activities. All samples in table 2 showed a much lower percentage inhibition value than that of the AA standard (125 \u0026micro;g/ml, 93.75 %\u0026plusmn;0.11). \u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u0026nbsp;Table 2\u003c/strong\u003e\u0026nbsp; Percentage inhibition of different CNC/ZnO samples\u0026nbsp;\u003c/p\u003e\n\u003ctable border=\"1\" cellpadding=\"0\" cellspacing=\"0\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd rowspan=\"2\" valign=\"top\" width=\"16.614420062695924%\"\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp; Samples\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"5\" valign=\"top\" width=\"83.38557993730407%\"\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp;Concentration \u0026nbsp;ration \u0026nbsp; \u0026nbsp; (\u0026micro;g/ml)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"20%\"\u003e\n \u003cp\u003e25\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"20%\"\u003e\n \u003cp\u003e50\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"20%\"\u003e\n \u003cp\u003e75\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"20%\"\u003e\n \u003cp\u003e100\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"20%\"\u003e\n \u003cp\u003e125\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"16.666666666666668%\"\u003e\n \u003cp\u003eCNC/ZnO\u003csub\u003e1\u003c/sub\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"16.666666666666668%\"\u003e\n \u003cp\u003e11.09\u0026plusmn;1.21\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"16.666666666666668%\"\u003e\n \u003cp\u003e21.43\u0026plusmn;2.11\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"16.666666666666668%\"\u003e\n \u003cp\u003e32.07\u0026plusmn;0.74\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"16.666666666666668%\"\u003e\n \u003cp\u003e42.51\u0026plusmn;0.62\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"16.666666666666668%\"\u003e\n \u003cp\u003e53.15\u0026plusmn;1.03\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"16.666666666666668%\"\u003e\n \u003cp\u003eCNC/ZnO\u003csub\u003e3/4\u003c/sub\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"16.666666666666668%\"\u003e\n \u003cp\u003e10.78\u0026plusmn;1.31\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"16.666666666666668%\"\u003e\n \u003cp\u003e21.21\u0026plusmn;1.91\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"16.666666666666668%\"\u003e\n \u003cp\u003e31.73\u0026plusmn;0.91\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"16.666666666666668%\"\u003e\n \u003cp\u003e42.06\u0026plusmn;0.57\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"16.666666666666668%\"\u003e\n \u003cp\u003e52.58\u0026plusmn;0.65\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"16.666666666666668%\"\u003e\n \u003cp\u003eCNC/ZnO\u003csub\u003e1/2\u003c/sub\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"16.666666666666668%\"\u003e\n \u003cp\u003e9.10\u0026plusmn;0.45\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"16.666666666666668%\"\u003e\n \u003cp\u003e17.73\u0026plusmn;0.34\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"16.666666666666668%\"\u003e\n \u003cp\u003e26.48\u0026plusmn;0.34\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"16.666666666666668%\"\u003e\n \u003cp\u003e35.33\u0026plusmn;0.56\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"16.666666666666668%\"\u003e\n \u003cp\u003e44.08\u0026plusmn;0.34\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"16.666666666666668%\"\u003e\n \u003cp\u003eCNC/ZnO\u003csub\u003e1/4\u003c/sub\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"16.666666666666668%\"\u003e\n \u003cp\u003e6.22\u0026plusmn;0.26\u003csup\u003ec\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"16.666666666666668%\"\u003e\n \u003cp\u003e12.25\u0026plusmn;1.45\u003csup\u003ec\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"16.666666666666668%\"\u003e\n \u003cp\u003e18.17\u0026plusmn;2.45\u003csup\u003ec\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"16.666666666666668%\"\u003e\n \u003cp\u003e24.30\u0026plusmn;0.54\u003csup\u003ec\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"16.666666666666668%\"\u003e\n \u003cp\u003e30.12\u0026plusmn;0.76\u003csup\u003ec\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"16.666666666666668%\"\u003e\n \u003cp\u003eCNC\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"16.666666666666668%\"\u003e\n \u003cp\u003e1.21\u0026plusmn;0.23\u003csup\u003ed\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"16.666666666666668%\"\u003e\n \u003cp\u003e2.31\u0026plusmn;0.43\u003csup\u003ed\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"16.666666666666668%\"\u003e\n \u003cp\u003e3.41\u0026plusmn;0.19\u003csup\u003ed\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"16.666666666666668%\"\u003e\n \u003cp\u003e4.51\u0026plusmn;0.27\u003csup\u003ed\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"16.666666666666668%\"\u003e\n \u003cp\u003e5.61\u0026plusmn;0.39\u003csup\u003ed\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"16.666666666666668%\"\u003e\n \u003cp\u003eAA\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"16.666666666666668%\"\u003e\n \u003cp\u003e51.15\u0026plusmn;0.65\u003csup\u003ee\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"16.666666666666668%\"\u003e\n \u003cp\u003e62.42\u0026plusmn;2.34\u003csup\u003ee\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"16.666666666666668%\"\u003e\n \u003cp\u003e74.53\u0026plusmn;0.97\u003csup\u003ee\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"16.666666666666668%\"\u003e\n \u003cp\u003e80.61\u0026plusmn;0.32\u003csup\u003ee\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"16.666666666666668%\"\u003e\n \u003cp\u003e93.75\u0026plusmn;0.11\u003csup\u003ee\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e\u003cem\u003eAll data were examined in triplicate, and the mean value\u0026nbsp;\u003c/em\u003e\u0026plusmn; SD \u003cem\u003ewas taken and written in the table. The identical alphabetical letter indicates that there are no statically significantly different (P\u0026gt;0.05) between values in the same column. AA= ascorbic acid\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003eThe IC50 values of CNC/ZnO samples are presented in Fig. 10. Their value ranged from 117.66 \u0026plusmn; 2.07\u0026mu;g/ml to 554.30 \u0026plusmn; 2.07\u0026mu;g /ml. All CNC/ZnO samples had IC50 values that were greater (P \u0026lt; 0.05) than ascorbic acid, indicating that they are the least effective in scavenging DPPH radicals compared to standards. CNC samples without ZnO have the largest (554.30\u0026plusmn; 2.11), and AA has the lowest (19.30 \u0026plusmn;1.03) IC50 value. There is no significant (P \u0026gt; 0.05) IC50 value difference between CNC/ZnO\u003csub\u003e1\u003c/sub\u003e and CNC/ZnO\u003csub\u003e3/4\u0026nbsp;\u003c/sub\u003esamples. Since the antioxidant activities and IC50 value have inversely proportional values, the results showed that CNC had the lowest antioxidant activities, whereas CNC/ZnO\u003csub\u003e1\u003c/sub\u003e had the highest antioxidant activities.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eThe results from both % inhibition and IC50 values demonstrated that when Zn\u003csup\u003e2+\u003c/sup\u003e concentrations increase, the antioxidant activities of the samples to scavenge free radicals also increase. As ZnO nanoparticle concentrations rise, more DPPH free radicals are quenched. This results in to increase the antioxidant activities. Similar work was done by \u0026nbsp;Ali et al. (2016). Their work showed that ZnO-Cellulose showed lower DPPH free radical scavenging activities (14.85%) than the present work. The study also revealed that DPPH scavenging activity was shown to rise with a rise in nanoparticle concentrations. This characteristic is also observed in this work.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e3.6.3 Antibacterial activities \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe lack of antibacterial activities in cellulose may restrict its usage in biomedical and environmental applications. This is why researchers are initiated to synthesize zinc nanocomposites with cellulose for antibacterial activities (Azizi et al. 2014; Ul-Islam et al. 2014). \u0026nbsp; By converging cellulose into CNC and preparing CNC/ZnO. We made cellulose to have antibacterial activities (Fig. 11).\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eIn this study, gram-negative bacteria species such as \u003cem\u003eEscherichia coli\u003c/em\u003e and \u003cem\u003eKlebsiella pneumonia\u003c/em\u003e, as well as gram-positive bacteria including \u003cem\u003eStaphylococcus aureus\u003c/em\u003e and \u003cem\u003eStaphylococcus epidermidis\u003c/em\u003e, were used to investigate the antibacterial efficacy of the CNC/ZnO nanohybrids. The CNC was used as a control sample. The Ciprofloxacin drug was employed as a standard sample in the Agar well diffusion method to examine the antibacterial activity.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eThe disc diffusion method was used to assess the antibacterial activity. It was shown that the inhibition zones produced by CNC/ZnO nanohybrids against \u003cem\u003eEscherichia coli\u003c/em\u003e and \u003cem\u003eKlebsiella pneumonia\u003c/em\u003e ranged from 32.33 2.51 to 41.33 1.15 and 31.66 3.51 to 41.00 1, respectively\u003cem\u003e. For gram-positive bacteria species such as Staphylococcus aureus and\u0026nbsp;\u003c/em\u003e\u003cem\u003eStaphylococcus \u003cem\u003eepidermidis,\u0026nbsp;\u003c/em\u003e\u003c/em\u003ezone inhibition was observed in the range of 26.00\u0026plusmn;1.00 to 40.33\u0026plusmn;2.08 and 31.22\u0026plusmn;1.52 to 38.66\u0026plusmn;1.15 respectively.\u0026nbsp;The standard drug in this investigation, Ciprofloxacin, demonstrated a 30 00\u0026plusmn;0.00\u0026nbsp;zone of inhibition for testing four bacterial species. \u0026nbsp; \u0026nbsp;\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eThe size of the growth-inhibiting ring used to combat \u003cem\u003eStaphylococcus aureus \u003cem\u003eagainst four different samples such as\u0026nbsp;\u003c/em\u003e\u003c/em\u003eCNC/ZnO\u003csub\u003e1/4\u003c/sub\u003e, CNC/ZnO\u003csub\u003e1/2\u003c/sub\u003e, CNC/ZnO\u003csub\u003e3/4,\u003c/sub\u003e and CNC/ZnO\u003csub\u003e1\u003c/sub\u003e were \u0026nbsp;26.00\u0026plusmn; 1.00, 32.33\u0026plusmn; 2.51, 33.33\u0026plusmn; 2.88, and 40.33\u0026plusmn; 2.08 mm, respectively. This showed that as the concentration of Zn\u003csup\u003e2+\u003c/sup\u003e increases, the antibacterial activities of \u003cem\u003eStaphylococcus aureus also increase. However, this uniform trend is not observed for the other three bacteria species, such as\u0026nbsp;\u003c/em\u003e\u003cem\u003eEscherichia coli,\u003c/em\u003e\u003cem\u003e\u0026nbsp;Klebsiella \u003cem\u003epneumonia, and\u0026nbsp;\u003c/em\u003eStaphylococcus \u003cem\u003eepidermidis (Fig. 11). There was no significant difference (P\u003c/em\u003e\u003c/em\u003e\u003cem\u003e\u0026nbsp;in the value of disc diffusion between\u0026nbsp;\u003c/em\u003e\u003cem\u003eEscherichia coli\u0026nbsp;\u003c/em\u003eand\u0026nbsp;\u003cem\u003eKlebsiella \u003cem\u003epneumonia, almost in all concentrations. This showed that the antibacterial properties between these two species are almost the same.\u0026nbsp;\u003c/em\u003e\u003c/em\u003eThe inhibition zone of CNC/ZnO\u003csub\u003e1\u003c/sub\u003e (16.3\u0026plusmn;3.21mm), CNC/ZnO\u003csub\u003e3/4\u003c/sub\u003e (17.3\u0026plusmn;2.51 mm), CNC/ZnO\u003csub\u003e1/2\u003c/sub\u003e (17.3\u0026plusmn;2.51 mm), and CNC/ZnO\u003csub\u003e1/4\u0026nbsp;\u003c/sub\u003e(17.3\u0026plusmn;2.51 mm) against \u003cem\u003eEscherichia coli\u0026nbsp;\u003c/em\u003eand the inhibition zone of CNC/ZnO\u003csub\u003e1\u003c/sub\u003e (16.3\u0026plusmn;3.21mm), CNC/ZnO\u003csub\u003e3/4\u003c/sub\u003e (17.3\u0026plusmn;2.51 mm), CNC/ZnO\u003csub\u003e1/2\u0026nbsp;\u003c/sub\u003e(17.3\u0026plusmn;2.51 mm) and CNC/ZnO\u003csub\u003e1/4\u0026nbsp;\u003c/sub\u003e(17.3\u0026plusmn;2.51 mm) against \u003cem\u003eKlebsiella \u003cem\u003epneumonia\u003c/em\u003e\u003c/em\u003e were statistically significant (P\u0026lt;0.05) greater than inhibition zone of the corresponding samples of gram-positive bacteria species such as \u003cem\u003eStaphylococcus aureus\u003c/em\u003e and\u0026nbsp;\u003cem\u003eStaphylococcus \u003cem\u003eepidermidis\u003c/em\u003e\u003c/em\u003e. This showed that gram-negative bacteria respond more positively to antibacterial activities than gram-positive bacteria species. \u003cem\u003eEscherichia coli\u003c/em\u003e and \u003cem\u003eKlebsiella\u003c/em\u003e \u003cem\u003epneumonia\u003c/em\u003e, there was no statistically significant (P \u0026lt; 0.05) difference among the inhibition zone of CNC/ZnO\u003csub\u003e1\u003c/sub\u003e, CNC/ZnO\u003csub\u003e3/4,\u003c/sub\u003e and CNC/ZnO\u003csub\u003e1/4\u003c/sub\u003e. However, in \u003cem\u003eStaphylococcus aureus\u0026nbsp;\u003c/em\u003eand \u003cem\u003eStaphylococcus \u003cem\u003eepidermidis\u003c/em\u003e\u003c/em\u003e there was a statistically significant (P \u0026lt; 0.05) difference among inhibition zone against CNC/ZnO\u003csub\u003e1\u003c/sub\u003e, CNC/ZnO\u003csub\u003e3/4\u003c/sub\u003e, CNC/ZnO\u003csub\u003e1/2\u003c/sub\u003e and CNC/ZnO\u003csub\u003e1/4\u003c/sub\u003e.\u003c/p\u003e\n\u003cp\u003eThe inhibition zone of the standard drug\u0026nbsp;Ciprofloxacin (30.00\u0026nbsp;\u0026plusmn; 1.00) exhibited the lowest value except for the value of CNC/ZnO\u003csub\u003e1\u003c/sub\u003e against \u003cem\u003eStaphylococcus aureus\u0026nbsp;\u003c/em\u003e(26.00\u0026plusmn; 1.00). This showed that the synthesized CNC/ZnO samples have high antibacterial activities. The data in table 3 showed that as the concentration of ZnO nanohybrids increased, the % inhibition of the samples also increased. This showed that antibacterial activities are directly dependent on concentration. \u0026nbsp; \u0026nbsp; \u0026nbsp;\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eThe use of CNC/ZnO nanohybrids against\u0026nbsp;\u003cem\u003eStaphylococcus aureus\u003c/em\u003e and\u0026nbsp;\u003cem\u003eEscherichia coli\u003c/em\u003e has been reported by\u0026nbsp;\u0026nbsp;Abdalkarim et al. (2018b)\u0026nbsp;to inhibit the growth of bacteria and reduce bacterial counts. Despite using diluted nanocomposites, their findings indicated that the bacteria were inhibited in 4.5 and 3mm zones, respectively. This value is too small compared to our work. In another similar work by\u0026nbsp;\u0026nbsp;Abdalkarim et al. (2018a), zones of inhibition for the antibacterial activity of \u0026nbsp; CNC/ZnO nanohybrids against \u003cem\u003eStaphylococcus aureus\u003c/em\u003e and\u0026nbsp;\u003cem\u003eEscherichia coli\u0026nbsp;\u003c/em\u003ewere also observed to be 3.0 to 5.1 mm and 4.1 to 4.9 mm, respectively. This value is also small compared to our value.\u0026nbsp;\u0026nbsp;Yu et al. (2015)\u0026nbsp;discovered effective CNC/ZnO nanohybrid antibacterial activity against \u003cem\u003eStaphylococcus aureus\u0026nbsp;\u003c/em\u003eand \u003cem\u003eEscherichia coli\u003c/em\u003e, with the diameter of the growth inhibition ring measuring 4.5 and 4.3 mm, respectively. This value is also too small compared to the value found in our work (Fig. 11). \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp;\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eDue to the greater surface area of ZnO nanostructures, more ROS are produced. The bacteria become oxidized by the metal component, which renders their proteins inactive, decreases cell permeability, and finally results in their death. The generated ROS may penetrate and directly damage bacteria\u0026apos;s cell walls, causing peroxidation of the organism\u0026apos;s PUFA phospholipids and bacterial death (Wang et al. 2017; Sawai et al. 1996). Additionally, another bactericidal mechanism might result from electromagnetic interaction between the pathogen and the nanoparticles, which would halt the bacteria\u0026apos;s activity (Mohd Yusof et al. 2019).\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eTable 3\u003c/strong\u003e The zone of inhibition that CNC/ZnO showed against four bacteria pathogens such as \u0026nbsp;\u003cem\u003eStaphylococcus epidermidis, Staphylococcus aureus, Escherichia coli,\u0026nbsp;\u003c/em\u003eand \u003cem\u003eKlebsiella pneumonia,\u0026nbsp;\u003c/em\u003e\u003c/p\u003e\n\u003ctable border=\"1\" cellpadding=\"0\" cellspacing=\"0\" width=\"721\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd rowspan=\"2\" valign=\"top\" width=\"14.285714285714286%\"\u003e\n \u003cp\u003eBacteria species\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd rowspan=\"2\" valign=\"top\" width=\"10.818307905686547%\"\u003e\n \u003cp\u003eTrial\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"3\" valign=\"top\" width=\"46.601941747572816%\"\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; Samples\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"14.147018030513177%\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"14.147018030513177%\"\u003e\n \u003cp\u003eCiprofloxacin\u0026nbsp;(standard)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"20%\"\u003e\n \u003cp\u003eCNC/ZnO\u003csub\u003e1\u003c/sub\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"21.11111111111111%\"\u003e\n \u003cp\u003eCNC/ZnO\u003csub\u003e3/4\u003c/sub\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"21.11111111111111%\"\u003e\n \u003cp\u003eCNC/ZnO\u003csub\u003e1/2\u003c/sub\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"18.88888888888889%\"\u003e\n \u003cp\u003eCNC/ZnO\u003csub\u003e1/4\u003c/sub\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd rowspan=\"5\" valign=\"top\" width=\"18.88888888888889%\"\u003e\n \u003cp\u003e30.00\u0026plusmn; 00\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd rowspan=\"4\" valign=\"top\" width=\"16.63974151857835%\"\u003e\n \u003cp\u003e\u003cem\u003eEscherichia coli\u003c/em\u003e\u003c/p\u003e\n \u003cp\u003e(-ve)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"12.60096930533118%\"\u003e\n \u003cp\u003e1\u003csup\u003est\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"17.447495961227787%\"\u003e\n \u003cp\u003e30\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"18.416801292407108%\"\u003e\n \u003cp\u003e42\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"18.416801292407108%\"\u003e\n \u003cp\u003e40\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"16.478190630048466%\"\u003e\n \u003cp\u003e42\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"15.116279069767442%\"\u003e\n \u003cp\u003e2\u003csup\u003end\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"20.930232558139537%\"\u003e\n \u003cp\u003e32\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"22.093023255813954%\"\u003e\n \u003cp\u003e40\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"22.093023255813954%\"\u003e\n \u003cp\u003e40\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"19.767441860465116%\"\u003e\n \u003cp\u003e40\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"15.116279069767442%\"\u003e\n \u003cp\u003e3\u003csup\u003erd\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"20.930232558139537%\"\u003e\n \u003cp\u003e35\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"22.093023255813954%\"\u003e\n \u003cp\u003e41\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"22.093023255813954%\"\u003e\n \u003cp\u003e42\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"19.767441860465116%\"\u003e\n \u003cp\u003e42\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"15.116279069767442%\"\u003e\n \u003cp\u003eAverage\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"20.930232558139537%\"\u003e\n \u003cp\u003e32.33 \u0026plusmn; 2.51\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"22.093023255813954%\"\u003e\n \u003cp\u003e41\u0026plusmn; 1.00\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"22.093023255813954%\"\u003e\n \u003cp\u003e40.66 \u0026plusmn; 1.15\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"19.767441860465116%\"\u003e\n \u003cp\u003e41.33\u0026plusmn; 1.15\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd rowspan=\"4\" valign=\"top\" width=\"14.285714285714286%\"\u003e\n \u003cp\u003e\u003cem\u003eKlebsiella \u003cem\u003epneumonia\u003c/em\u003e\u003c/em\u003e\u003c/p\u003e\n \u003cp\u003e\u003cem\u003e(-ve)\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"10.818307905686547%\"\u003e\n \u003cp\u003e1\u003csup\u003est\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"14.979195561719834%\"\u003e\n \u003cp\u003e28\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"15.811373092926491%\"\u003e\n \u003cp\u003e38\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"15.811373092926491%\"\u003e\n \u003cp\u003e43\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"14.147018030513177%\"\u003e\n \u003cp\u003e40\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd rowspan=\"4\" valign=\"top\" width=\"14.147018030513177%\"\u003e\n \u003cp\u003e30.00\u0026plusmn; 00\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"15.116279069767442%\"\u003e\n \u003cp\u003e2\u003csup\u003end\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"20.930232558139537%\"\u003e\n \u003cp\u003e35\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"22.093023255813954%\"\u003e\n \u003cp\u003e40\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"22.093023255813954%\"\u003e\n \u003cp\u003e45\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"19.767441860465116%\"\u003e\n \u003cp\u003e41\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"15.116279069767442%\"\u003e\n \u003cp\u003e3\u003csup\u003erd\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"20.930232558139537%\"\u003e\n \u003cp\u003e32\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"22.093023255813954%\"\u003e\n \u003cp\u003e41\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"22.093023255813954%\"\u003e\n \u003cp\u003e40\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"19.767441860465116%\"\u003e\n \u003cp\u003e42\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"15.116279069767442%\"\u003e\n \u003cp\u003eAverage\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"20.930232558139537%\"\u003e\n \u003cp\u003e31.66\u0026plusmn; 3.51\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"22.093023255813954%\"\u003e\n \u003cp\u003e39.66\u0026plusmn; 1.52\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"22.093023255813954%\"\u003e\n \u003cp\u003e42.66\u0026plusmn; 2.51\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"19.767441860465116%\"\u003e\n \u003cp\u003e41.00\u0026plusmn; 1.00\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd rowspan=\"4\" valign=\"top\" width=\"14.285714285714286%\"\u003e\n \u003cp\u003e\u003cem\u003eStaphylococcus aureus\u003c/em\u003e\u003c/p\u003e\n \u003cp\u003e\u003cem\u003e(+ve)\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"10.818307905686547%\"\u003e\n \u003cp\u003e1\u003csup\u003est\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"14.979195561719834%\"\u003e\n \u003cp\u003e25\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"15.811373092926491%\"\u003e\n \u003cp\u003e30\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"15.811373092926491%\"\u003e\n \u003cp\u003e30\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"14.147018030513177%\"\u003e\n \u003cp\u003e38\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd rowspan=\"4\" valign=\"top\" width=\"14.147018030513177%\"\u003e\n \u003cp\u003e30.00\u0026plusmn; 00\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"15.116279069767442%\"\u003e\n \u003cp\u003e2\u003csup\u003end\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"20.930232558139537%\"\u003e\n \u003cp\u003e27\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"22.093023255813954%\"\u003e\n \u003cp\u003e35\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"22.093023255813954%\"\u003e\n \u003cp\u003e35\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"19.767441860465116%\"\u003e\n \u003cp\u003e42\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"15.116279069767442%\"\u003e\n \u003cp\u003e3\u003csup\u003erd\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"20.930232558139537%\"\u003e\n \u003cp\u003e26\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"22.093023255813954%\"\u003e\n \u003cp\u003e32\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"22.093023255813954%\"\u003e\n \u003cp\u003e35\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"19.767441860465116%\"\u003e\n \u003cp\u003e41\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"15.116279069767442%\"\u003e\n \u003cp\u003eAverage\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"20.930232558139537%\"\u003e\n \u003cp\u003e26.00\u0026plusmn; 1.00\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"22.093023255813954%\"\u003e\n \u003cp\u003e32.33\u0026plusmn; 2.51\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"22.093023255813954%\"\u003e\n \u003cp\u003e33.33\u0026plusmn; 2.88\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"19.767441860465116%\"\u003e\n \u003cp\u003e40.33\u0026plusmn; 2.08\u003csup\u003ec\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd rowspan=\"4\" valign=\"top\" width=\"14.285714285714286%\"\u003e\n \u003cp\u003e\u003cem\u003eStaphylococcus \u003cem\u003eepidermidis\u003c/em\u003e\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"10.818307905686547%\"\u003e\n \u003cp\u003e1\u003csup\u003est\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"14.979195561719834%\"\u003e\n \u003cp\u003e33\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"15.811373092926491%\"\u003e\n \u003cp\u003e32\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"15.811373092926491%\"\u003e\n \u003cp\u003e38\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"14.147018030513177%\"\u003e\n \u003cp\u003e38\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd rowspan=\"4\" valign=\"top\" width=\"14.147018030513177%\"\u003e\n \u003cp\u003e30.00\u0026plusmn; 00\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"15.116279069767442%\"\u003e\n \u003cp\u003e2\u003csup\u003end\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"20.930232558139537%\"\u003e\n \u003cp\u003e30\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"22.093023255813954%\"\u003e\n \u003cp\u003e30\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"22.093023255813954%\"\u003e\n \u003cp\u003e35\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"19.767441860465116%\"\u003e\n \u003cp\u003e40\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"15.116279069767442%\"\u003e\n \u003cp\u003e3\u003csup\u003erd\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"20.930232558139537%\"\u003e\n \u003cp\u003e31\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"22.093023255813954%\"\u003e\n \u003cp\u003e30\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"22.093023255813954%\"\u003e\n \u003cp\u003e38\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"19.767441860465116%\"\u003e\n \u003cp\u003e38\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"15.116279069767442%\"\u003e\n \u003cp\u003eAverage\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"20.930232558139537%\"\u003e\n \u003cp\u003e31.22\u0026plusmn; 1.52\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"22.093023255813954%\"\u003e\n \u003cp\u003e30.66\u0026plusmn; 1.15\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"22.093023255813954%\"\u003e\n \u003cp\u003e37\u0026plusmn; 1.73\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"19.767441860465116%\"\u003e\n \u003cp\u003e38.66\u0026plusmn; 1.15\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e"},{"header":"Conclusion ","content":"\u003cp\u003eThis research study synthesized CNC/ZnO through a simple and single-stage process. Data from SEM, XRD, DLS, and FTIR spectra showed that ZnO nanoparticles were loaded on carboxylated CNC to form a nanohybrid of CNC/ZnO with a mean size of 164.18 nm in the range between 94\u0026ndash;351 nm. ZnONPsare distributed around the CNC because of the electrostatic interaction between the Zn\u003csup\u003e2+\u003c/sup\u003e ion and the carboxyl group of the CNC. The synthesized CNC/ZnO nanohybrids showed high photocatalytic activities, with a 90% degradation rate of MB. The nanohybrid samples also showed higher antibacterial than CNC. All the samples exhibited high antibacterial activities against both grams positive (\u003cem\u003eKlebsiella\u003cem\u003epneumonia and\u003c/em\u003e Escherichia coli\u003c/em\u003e)\u0026nbsp;and gram-negative bacteria (\u003cem\u003eStaphylococcus \u003cem\u003eepidermidis and Staphylococcus aureus)\u0026nbsp;\u003c/em\u003e\u003c/em\u003ewith inhibition zone in the range of26.00\u0026plusmn;1.00 to 41.33\u0026plusmn; 1.15 mm compared to\u0026nbsp;Ciprofloxacin. The result also showed that CNC/ZnO nanohybrids have higher antioxidant activities than CNC. In the CNC sample, the lowest DPPH radical scavenging activities, 5.61\u0026plusmn;0.39, were observed.\u0026nbsp;The highest % inhibition of DPPH (53.15\u0026plusmn;1.03%) and the lowest IC50 value (117.66\u0026micro;m/ml) were observed in CNC/ZnO\u003csub\u003e1\u003c/sub\u003e sample. The above data showed that ZnO/CNC nanohybrid could be applied in dye removal, wastewater treatment, and antibacterial activity. ZnO/CNC nanohybrid showed weaker antioxidant activity in this study, necessitating further study in this area.\u0026nbsp;\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eAcknowledgments\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe Department of Industrial Chemistry at Addis Ababa Science and Technology University provided the opportunity for the authors to conduct this research. The only Doctoral Dissertation Research provided by Addis Ababa Science and Technology University, Ethiopia, was used. \u0026nbsp;\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eEthical approval\u003c/p\u003e\n\u003cp\u003eNot applicable\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCompeting interests\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors declare no competing interests\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eAuthors contributions\u003c/p\u003e\n\u003cp\u003eAll authors contributed to the study conception and design. Material preparation, data collection and analysis were performed by Limenew Abate Worku. The first draft of the manuscript was written by Rakesh Kumar Bachheti and Mesfin Getachew Tadesse. Archana Bachheti prepare different table and figures. All authors commented on previous versions of the manuscript. All authors read and approved the final manuscript. All authors also worked on revision of the article.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eData availability \u0026nbsp;\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003eAll data generated or analyzed during this study are included in this paper \u003cstrong\u003e\u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eFunding\u003c/p\u003e\n\u003cp\u003eThis study was financially supported by Addis Ababa science and Technology University. No external funding available \u0026nbsp; \u0026nbsp; \u0026nbsp;\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eAbdalkarim SYH, Yu HY, Wang C, Huang LX, Yao J (2018) Green synthesis of sheet-like cellulose nanocrystal\u0026ndash;zinc oxide nanohybrids with multifunctional performance through one-step hydrothermal method. \u003cem\u003eCellulose \u003c/em\u003e 25(11):6433-6446.\u003c/li\u003e\n\u003cli\u003eAbdalkarim SYH, Yu HY, Wang C, Yang L, Guan Y, Huang L, Yao J (2018) Sheet-like cellulose nanocrystal-ZnO nanohybrids as multifunctional reinforcing agents in biopolyester composite nanofibers with ultrahigh UV-shielding and antibacterial performances. \u003cem\u003eACS Applied Bio Material .\u003c/em\u003e1(3):714-727.\u003c/li\u003e\n\u003cli\u003eAbouzeid RE, Khiari R, El-Wakil N, Dufresne A (2018) Current state and new trends in the use of cellulose nanomaterials for wastewater treatment. \u003cem\u003eBiomacromolecules \u003c/em\u003e 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Nanoparticle Res \u003c/em\u003e 16(6):1-10.\u003c/li\u003e\n\u003cli\u003eZhang G, Liu Y, Morikawa H, Chen Y (2013) Application of ZnO nanoparticles to enhance the antimicrobial activity and ultraviolet protective property of bamboo pulp fabric. \u003cem\u003eCellulose \u003c/em\u003e 20(4):1877-1884.\u003c/li\u003e\n\u003cli\u003eZhao D, Zhu Y, Cheng W, Chen W, Wu Y, Yu H (2021) Cellulose‐based flexible functional materials for emerging intelligent electronics.\u003cem\u003e Adv Mater \u003c/em\u003e 33(28):2000619.\u003c/li\u003e\n\u003cli\u003eZheng T, Pilla S: Melt processing of cellulose nanocrystal-filled composites (2020) Toward reinforcement and foam nucleation.\u003cem\u003e Ind Eng Chem Res \u003c/em\u003e 59(18):8511-8531. \u003c/li\u003e\n\u003c/ol\u003e"},{"header":"Scheme 1","content":"\u003cp\u003eScheme 1 is available in the Supplementary Files section.\u003c/p\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"CNC/ZnO nanohybrids, Carboxylated cellulose nanocrystal, Antibacterial activities, Photocatalytic activities, Oxytenanthera abyssinica ","lastPublishedDoi":"10.21203/rs.3.rs-2225634/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-2225634/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"In this study, cellulose from Oxytenanthera abyssinica was hydrolyzed to create carboxylated cellulose nanocrystals in a solution of citric acid and sulfuric acid. Afterward, nanohybrids were synthesized using carboxylated cellulose nanocrystals, zinc nitrate hexahydrate for photocatalytic degradation, and antibacterial and antioxidant properties. The experimental results were characterized using FTIR, XRD, SEM, and UV-Vis spectroscopy. Data from SEM, XRD, DLS, and FTIR spectra showed that ZnO nanoparticles were loaded on carboxylated CNC to form a nanohybrid of CNC/ZnO with mean nanoparticles size of 164.18 nm and size distribution between 94–351 nm. The data showed CNC/ ZnO nanohybrid had higher antibacterial, photocatalytic and antioxidant activities than CNC. The higher antibacterial activity was observed against both grams positive (Klebsiella pneumonia and Escherichia coli) and gram-negative bacteria (Staphylococcus epidermidis and Staphylococcus aureus) with an inhibition zone of 26.00±1.00 to 41.33±1.15 mm in comparison with Ciprofloxacin. The maximal amount of methylene blue photodegradation (about 91.52%) was seen after 75 minutes of exposure to a UV lamp. 53.151.03% DPPH radical scavenging actives with IC50 value of 117.66 µm/ml were obtained at 125 µm/ml concentration of CNC/ZnO sample. Biomedical and environmental applications of cellulose are limited by its extremely low antibacterial, photocatalytic, and antioxidant properties. Therefore, this study was done to enhance these properties by synthesizing a nanohybrid of cellulose nanocrystals from cellulose produced from Oxytenanthera abyssinica and ZnO inorganic salt.","manuscriptTitle":"Synthesis, characterization, and application of nanohybrid formed by mixing carboxylated cellulose nanocrystal and zinc nitrate hexahydrate by precipitation method using Oxytenanthera abyssinica as raw material","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2022-11-04 20:52:05","doi":"10.21203/rs.3.rs-2225634/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"0bada627-558f-42f1-90fa-c1eb4d6570a6","owner":[],"postedDate":"November 4th, 2022","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2023-01-28T02:44:19+00:00","versionOfRecord":[],"versionCreatedAt":"2022-11-04 20:52:05","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-2225634","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-2225634","identity":"rs-2225634","version":["v1"]},"buildId":"_2-kVJe1T_tPrBINL-cwx","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}