Facile Synthesis of chitosan-g-PVP/f-MWCNTs for application in Cu(II) ions removal and for bacterial growth inhibition in aqueous solutions

Facile Synthesis of chitosan-g-PVP/f-MWCNTs for application in Cu(II) ions removal and for bacterial growth inhibition in aqueous solutions | 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 Article Facile Synthesis of chitosan-g-PVP/f-MWCNTs for application in Cu(II) ions removal and for bacterial growth inhibition in aqueous solutions Samira T. Rabei, Yasser Mahmoud A Mohamed, Reham A Abdel-Monem, and 1 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-1640092/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted 9 You are reading this latest preprint version Abstract Chitosan-grafted-4-vinylpyridine (Cs-g-PVP) was prepared utilizing free radical copolymerization method. The chemical structure of the produced Cs-g-PVP was confirmed by FTIR spectroscopy, in addition thermal gravimetric analysis (TGA) was used to assess its thermal stability, and scanning electron microscopy (SEM) was used to examine its morphology. Enhancement of the chemical and physical proprieties was achieved by adding functionalized multi-walled carbon nanotubes (f-MWCNTs) to produce two polymeric hybrids of Cs-g-PVP/f-MWCNTs (I and II) with 3wt% and 5wt% f-MWCNTs, respectively. Characterization of these hybrids was performed using TGA, SEM and EDX analysis. Using a batch adsorption approach, the produced grafted copolymer (Cs-g-PVP) and the hybrids (Cs-g-PVP/f-MWCNTs I and II) were tested for adsorption of Cu(II) ions in aqueous solution using initial concentration of CuCl 2 equals to 5x10 − 3 mol/L at different pH values (i.e. 4, 7, and 9). Antibacterial activity of the Cs-g-PVP and the hybrids was evaluated against three Gram + ve bacteria ( Staphylococcus aurous , Bacillus Subtitles and Streptococcus faecalis ) and three Gram –ve bacteria ( Escherichia coli , Pseudomonas aeruginosa and Neisseria gonorrhoeae . The results showed that the efficiency of the Cs-g-PVP copolymer showed significant increase after inclusion of the f-MWCNTs substrate towards Cu(II) removal and antibacterial agent. Chitosan-grafted-4-vinylpyridine Carbon nanotubes C(II) ions removal Antibacterial activity Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Introduction Chitosan is a natural biopolymer with a linear polysaccharide structure and is found as an N-deacetylated chitin derivative [ 1 ]. Chitosan possesses a number of desirable characteristics, including biocompatibility, biodegradability, antibacterial activity, non-toxicity, and a variety of other physical features [ 2 ]. As a result, this essential natural biopolymer may be applied widely in a variety of disciplines, including medicine, cosmetics, food processing, waste water treatment, and environmental protection [ 3 – 5 ]. Previous work showed that Cs has the ability to inhibit the growth of many species of microbes in dilute acidic environment because it carries positive charges that can interact with the negatively charged molecular cell membranes of microorganisms. These microorganisms' molecular cell membranes may rupture or be damaged as a result of this electrostatic contact [ 6 ]. Chitosan adsorbs metal ions and removes metallic contaminants from wastewaters. As a result of the presence of both amine and hydroxyl groups as chelating sites for metal ions, chitosan is regarded to be a suitable chelating agent [ 7 – 9 ]. Chemical grafting of chitosan improves its chelating characteristics [ 10 – 11 ], antibacterial activity [ 12 ], and other features for a variety of applications. Chitosan graft copolymerization is a significant modification approach for affording new and various molecular designs of good types of hybrid materials containing bio- and synthetic polymeric components [ 13 ]. Cs-g-PAN is obtained by graft copolymerizing chitosan with acrylonitrile utilizing a free radical copolymerization procedure with potassium persulfate as the initiator. Some positive and negative gram bacterial strains demonstrated good antibacterial activities when grafted chitosan was used [ 14 ]. Nitrogen-containing polymers or copolymers, such as polyaniline and various polyhexamethylene guanidine derivatives, have been shown to have high metal adsorption affinities [ 15 ]. Heavy metal removal was achieved using a homopolymer and a few copolymers containing 4-vinylpyridine [ 16 – 17 ]. 4-VP has also been grafted onto polystyrene or copolymerized with divinyl sulfide to produce a resin with good metal adsorption characteristics [ 18 – 19 ]. New materials that can withstand the microbiological growth of some pathogens in the hospital environment have recently been tested. Using both native and functionalized versions of MWCNTs at concentrations of 50 and 100 g/ ml, different dosages of MWCNTs on the inhibitory effect were determined [ 20 ]. MWCNTs have additional advantages and potential features for use as inorganic fillers in polymeric substrate reinforcement [ 21 ]. Alumina and functionalized MWCNTs were incorporated into chitosan to increase certain of its physicochemical qualities, such as thermal stability, while reducing the chitosan's swell ability and solubility. Cs-alumina/f-MWCNTs nanocomposites have an antibacterial effect comparable to pure chitosan. As a result, even at low pH and high temperatures, these produced Cs-alumina/f-MWCNTs could be employed as effective antibacterial agents [ 22 ]. Cu (II), Cd (II), Pb (II), and Zn (II) were all removed from aqueous solutions using multiwalled carbon nanotubes that had been treated with 8-hydroxyquinoline. The effects of several parameters on metal adsorption by MWCNTs, such as dosages, metal ion concentrations, temperature, and pH values, were studied [ 23 ]. The development and characterization of a chitosan grafted-4-vinylpyridine copolymer to be used as a metal removal and antibacterial agent from aqueous solution were the focus of this work. This research went on to look at grafting two different weight percentages of f-MWCNTs into the grafted copolymer to create two hybrids and see how they affected metal removal and bacterial growth suppression in aqueous solution. Experimental 2.1. Materials Chitosan (MW 100– 300 kDa, 82% degree of deacetylation) was purchased from Across Organics, Belgium. Potassium persulfate (KPS), CuCl 2 and 4-vinylpyridine were supplied from Sigma Aldrich. MWCNTs were purchased from Sigma-Aldrich Company. All other fine chemicals were of fine grades and all solvents were distilled before use. 2.2. Characterization techniques and analysis 2.2.1. FTIR Spectroscopy FTIR spectra were recorded on Shimadzu IR-Spectrometer (FTIR 8201) Japan, at room temperature within the wavenumber range of 4000 to 400 cm−1 using KBr discs. 2.2.2. Thermogravimetric Analysis (TGA) Thermogravimetric analysis was carried out on TGA-50H thermogravimetric analyzer, Shimadzu, Japan. Samples were heated up to 800 ∘ C in a platinum pan with a heating rate of 10∘ C/min, in N 2 atmosphere of flow rate 25 mL/min. 2.2.3. Scanning Electronic Microscopy (SEM) The dry samples were spread on a conducting adhesive tape, pasted on a metallic stub. The morphologies of the tested samples were investigated and imaged with scanning electron microscope (SEM) (QUANTA FEG 250 ESEM, USA). This was accompanied by energy dispersive X-ray spectroscopy (EDAX AMETEK Inc.; Mahwah, NJ, USA) at an acceleration voltage of 15 kV. The films were fixed on the surface of a sticky tape 2.3. Preparation of chitosan graft-poly(4-vinylpyridine) Chitosan solution was prepared by dissolving 0.8 g of chitosan in 100 ml of 1% aqueous acetic acid solution and was placed in a flat bottomed three necked flask with stirring and the reaction temperature was raised to 60 o C. Then, nitrogen gas was purged into the reaction mixture at a constant temperature (ca ~60 ◦ C) with continuous stirring. Freshly prepared potassium persulfate solution (3×10 −2 mol/L) was added and then (2 mol/L) of 4-vinylpyridine was subsequently added by dropwise addition. The reaction was conducted for 2 h with stirring and continued for another 15 min at room temperature. Then the reaction product was precipitated out with 10% of (NaOH/MeOH) mixture, filtered, and dried. It was subjected to Soxhlet extraction for 8–12 h using N,N-dimethylformamide (DMF) to solubilize and remove any homopolymer [24]. The preparation of the chitosan grafted copolymer was illustrated in Scheme 1. The graft yield (G%), the grafting efficiency (GE%) and the amount of homopolymer (H%) formed were calculated according to the following equation Graft yield (G%) = [(W 1 −W 0 )/W 0 ] × 100 Grafting efficiency (GE%) = (W 1 /W 2 ) × 100 Where W 0 , W 1 are the weights of initial matrix and grafted matrix (i.e), weight of the product after extraction, respectively [25]. 2.4. Preparation of functionalized and Cs-g-PVP/MWCNTs hybrids The multi-walled carbon nanotubes (MWCNTs) were purchased from Sigma-Aldrich Company. Functionalization of MWCNTs was performed as reported before [26-27]. 0.5 g of MWCNTs was dispersed in 100 mL 65% nitric acid at 120 o C for 15h under magnetic stirring. The obtained solution was then washed with water several times to neutrality, filtered and finally dried at 80 ᵒC for 12h to obtain the functionalized MWCNTs, f-MWCNTs, samples which are ready now for use. To a predetermined weight of the grafted copolymer Cs-g-PVP in 20 mL of distilled water, f-MWCNTs (3wt% or 5wt% by weight of the grafted copolymer) was added and left for 30 min under magnetic stirring and then sonicated for another 30 min to obtain Cs-g-PVC/MWCNTs hybrids. A schematic representation was given to explain the formation of Cs-g-PVP/f-MWCNT hybrid, scheme 2. 2.5. Metal ion adsorption measurements using a batch method The batch adsorption experiments were performed by taking 20 mL of metal ion solution with a concentration of 5x10 -3 mol/L and pH (4, 7 and 9) in the Erlenmeyer flask; The solutions pH was adjusted using acetic acid/sodium acetate (AcOH/NaOAc) and NH 4 OH/NH 4 Cl buffer solutions to study the metal uptake at both the alkaline and the acidic mediums (pH 4 and 9) respectively. A predetermined weight of the prepared adsorbent copolymer (0.05, 0.10, 0.15 and 0.20 g) was added and the adsorption equilibrium was reached after 50 min of magnetic stirring at 25 ᵒC. After separation of the phases by centrifugation (10,000 rpm), the amount of metal-ion uptake of the polymers was determined by using atomic absorption spectrometry (AAS). 2.6. Antibacterial activity Antibacterial activity of the tested samples was evaluated using a modified Kirby-Bauer disc diffusion method [28]. Briefly, 100mL of the test bacteria were grown in 10 mL of fresh media until they reached a count of approximately 108 cells/mL for bacteria [29]. 100 mL of microbial suspension were spread onto agar plates corresponding to the broth in which they were maintained. Isolated colonies of each organism, that might be playing a pathogenic role, should be selected from primary agar plates. They were examined for susceptibility by disc diffusion method [30-31]. Of the many media available, National Committee of Clinical Laboratory Standards (NCCLS) recommends Mueller-Hinton agar due to its good results in batch to–batch reproducibility. Antibacterial activity of the prepared hydrogels was investigated against three types of Gram +ve bacteria ( Staphylococcus aurous , Bacillus Subtitles and Streptococcus faecalis ) and three Gram –ve bacteria ( Escherichia coli , Pseudomonas aeruginosa and Neisseria gonorrhoeae . Plates are inoculated with bacteria at 35–37ᵒC for 24–48 h [28]. Standard discs of Ampicillin (Antibacterial agent) have served as positive controls for antibacterial activity but filter discs impregnated with 10mL of solvent (distilled water, chloroform, DMSO) have been used as a negative control. The agar used is Meuller-Hinton agar that is rigorously tested for composition and pH. Further, the depth of the agar in the plate is considered to be a factor in the disc diffusion method. This method is well documented and standard inhibition zones have been determined for susceptible and resistant values. Blank paper discs (Schleicher and Schuell, Spain) with a diameter of 8.0 mm were impregnated with 10 m of tested concentration of the stock solutions. When a filter paper disc, impregnated with a tested chemical- is placed on agar, the chemical will diffuse from the disc into the agar. This diffusion will place the chemical on the agar only around the disc. The size of the area of chemical in filtration around the disc was determined by solubility of the chemical and its molecular size. If an organism is placed on the agar, it will not grow around the disc if it is susceptible to the chemical. This area of no growth around the disc is known as a “zone of Inhibition” or “clear zone.” For the disc diffusion, the zone diameters were measured with slipping calipers of the NCCLS [29]. Agar based methods such as E-test and disc diffusion are considered to be good alternatives because they are simpler and faster than broth-based methods [32-33]. Results And Discussion Cs-g-PVP was obtained by grafting 4-vinylpyridine copolymerization onto chitosan as described in the experimental section. According to the given equations in the experimental section, the grafting (G %) and grafting efficiencies (GE%) were calculated to be 92 and 236 %, respectively. FTIR spectroscopic analysis was used to confirm the grafted copolymer that had been formed. In addition, Cs-g-PVP/f-MWCNTs hybrids containing 3wt% and 5wt% of f-MWCNTs were also prepared. The affinity of the obtained grafted copolymer and its hybrids for copper ions adsorption was determined using batch adsorption method and metal removal % was determined using atomic absorption spectrometry (AAS). The effect of pH and the adsorbent mass on % metal removal was studied. Thermal stability of the copolymer, Cs-g-PVP and the two hybrids was determined via thermal gravimetric analysis, TGA, whereas scanning electron microscopy was applied for morphological studies of these samples. Antimicrobial activity of the all-prepared samples was evaluated. 3.1. FTIR analysis The evidence of the formation of Cs-g-PVP was achieved by FTIR analysis. Figure 1 (a,b) represented the FTIR spectrum of both Cs and Cs-g-PVP. It was clearly shown a strong IR band at 3433 cm -1 which should be assigned to the symmetrical stretching vibration of the OH groups, the extension vibration of the NH 2 , and the intermolecular hydrogen bonds of the polysaccharide. There are also two IR peaks appeared at 2918 and 2851 cm -1 that may be due to the aliphatic CH 2 and CH. The C-O absorption peak of the hydroxyl group was observed to 1068 cm -1 . In Figure 1, the grafting of 4-vinylpyridine onto chitosan was confirmed by the presence of C=N groups band at about 2120 cm −1 from the poly 4-vinylpyridine chains and the –CH bending of the aromatic ring of the vinyl pyridine that appeared around 746, 821, and 1601 cm -1 and this is very indicative to the grafting copolymerization of vinyl pyridine moiety with chitosan [34]. 3.2. Thermogravimetric analysis TGA analysis of Cs, Cs-g-PVP, Cs/f-MWCNTs and Cs-g-PVP/f-MWCNTs hybrid that containing 5% by weight of f-MWCNTs are shown in Figure 2. The thermogram revealed that Cs-g-PVP has a relative higher thermal stability than Cs in terms of both initial decomposition temperature (IDT) and residual weight below 500 o C,. The effect of f-MWCNTs (5wt% by weight) in both Cs and the grafted copolymer was investigated, and the results revealed that both Cs/f-MWCNTs and Cs-g-PVP/f-MWCNTs hybrids had significant higher thermal stability than either Cs or Cs-g-PVP. For example, at 250 ᵒC, the recorded weight loss of Cs, Cs-g-PVP, Cs/MWCNTs and Cs-g-PVP/MWCNTs hybrids are 27%, 31%, 13% and 10% respectively. The improved thermal stability of the two hybrids was found to be so significant at the decomposition temperature of 300 o C. The weight loss of Cs/f-MWCNTs and Cs-g-PVP/f-MWCNTs hybrids are 21% and 11% whereas the percentages weight loss of both Cs and Cs-g-PVP are 57 and 49 respectively. Cs and Cs-g-PVP hybrids lost 66% and 57% of their weight respectively, at 400 o C while Cs/f-MWCNTs and Cs-g-PVP/f-MWCNT hybrids lost 47% and 43% of their weight at the same temperature. At 515 o C, both Cs/f-MWCNTs and Cs-g-PVP/f-MWCNTs hybrids have almost the same weight loss of about 58 %, whereas Cs and Cs-g-PVP exhibited weight loss of 88 and 75 %, respectively. The thermal properties of the samples under investigation are shown in Table1. It showed the residual weights of the tested samples at 400 and 500 ᵒC, as well as the temperatures at which they lost 10 and 50% of their weight. The observed weight loss in the early stages of degradation for all investigated samples might be attributed to any attached water residues or volatiles being released from the polymeric chains. The observed degradation of Cs could be due to dehydration and depolymerization of Cs units, which increases as the polymeric network structure proceeds [35-36]. The presence of a PVP block in the grafted copolymer, with its better thermal stability due to the presence of the aromatic ring in the chemical structure of PVP, could explain the higher thermal stability of Cs-g-PVP than Cs. It was demonstrated that the thermal stability of Cs and the grafted copolymeric matrix of Cs-g-PVP was improved by incorporation f-MWCNTs in 3wt% and 5wt% by weight, resulting in two hybrids. The barrier function of the f-MWCNTs may be responsible for this improved thermal stability. Table 1 . Thermal properties of various investigated samples Sample T 10% T 50% R 400% R 500% Cs 53 277 34 13 Cs-g-PVP 207 310 43 26 Cs/MWCNTs (3wt%) 213 423 53 43 Cs-g-PVP/ MWCNTs (5wt%) 229 436 57 43 3.3. Scanning electron microscopy SEM images of Cs and Cs-g-PVP Cs-g-PVP/f-MWCNTs (I and II) hybrids and are shown in Figure 3 (a-d). The morphology of the chitosan was depicted in Figure 3 (a). Upon graphitization of Cs with 4-VP, to obtain Cs-g-PVP, an obvious change in the surface morphology of the grafted chitosan that gave a proof for conjugation of 4-VP blocks in the copolymer chains and this is represented in Figure 3 (b). By treating chitosan grafted- 4-vinylpyridine copolymer with f-MWCNTs (3wt% and 5wt%,). It was apparently shown that the functionalized MWCNTs are bonded to chitosan-g-PVP. The f-MWCNTs was appeared in micron length sizes with distinct agglomeration in the surface of the formed polymeric composite. 3.4 Batch adsorption studies Batch adsorption experiments were performed using Cs-g-PVP, Cs-g-PVP/f-MWCNTs hybrid (containing 3wt% and 5wt% by weight) as polymeric adsorbent according to the method described before in the experimental part. Cs and Cs/f-MWCNTs was also examined as metal adsorbent for comparison. Metal solutions with concentration of 5x10 -3 mol/L of CuCl 2 . 2H 2 O at pH (4, 7 and 9), adsorbent copolymer (0.05, 0.10, 0.15 and 0.20 g) were applied and the effect of both pH and copolymer mass will be discussed. 3.4.1. Effect of pH and adsorbent mass on metal removal by the graft copolymers Cs-g-PVP The results of copper (II) uptake by the produced Cs-g-PVP as a function of pH and mass adsorbent are shown in Figure 4. The applied masses of the grafted copolymer as adsorbent are; 0.05, 0.10, 0.15 and 0.20 g whereas the working pH values are 4, 7 and 9. The results show that when different masses of adsorbent were used, the metal removal % increase as the pH increase from 4 to 7 [37], but there was a considerable reduction at pH 9. Figure 4 indicates that both the pH and the adsorbent mass have an impact on the metal removal % of copper (II) from aqueous solutions. For adsorbent masses of 0.05, 0.10, 0.15, and 0.20 g, the metal removal % was 21.08, 26.22, 28.75, and 29.17 at pH 4. At pH 7, the percentages of metal removal for the same copolymer masses are 35.54, 38.38, 39.32, and 40.09. It is noticed that at pH 9 these percentages are reduced to be 30.27, 32.17, 34.59 and 35.12. The increase of metal removal by the increase of pH from 4 to 7 may be due to the remarkable hydrolysis of the copper (II) ions at higher pH and this may compete with polymer chelation process. In all cases, the pH highly affects the oxygen atoms of OH or the lone pairs of electrons on the nitrogen atoms of the adsorbent. At higher values of pH, the OH may lose its proton and bear a negative charge while the nitrogen atom lone pair will be more available for binding to metal ions and this increase the attraction of metallic ions onto the surface of adsorbent [38]. This decrease occurred at pH 9 for all masses of the adsorbent which may be due to the precipitation of the metal hydroxides in the basic solution [39]. The given results show also that at all pH values, the % of metal removal is increased with the increase of the copolymer mass. At pH 7, the metal removal percentages are 35.54%, 38.38%, 39.32% and 40.09% for the adsorbent masses of 0.05 g, 0.10 g, 0.15 g and 0.2 g respectively. It noticed also that there is slight increase in the metal ion uptake on increasing the copolymer mass from 0.15 g to 0.20 g. The increase of the removal of Cu(II) ions with increasing the mass of adsorbent which is directly proportional to the adsorption capacity by the grafted copolymer, may be due to the increase of the polymer sites available for chelation. The effect of the mass of adsorbent on the extent of metal removal was also investigated and the results reveal that removal of Cu (II) ions increases with increasing the mass of adsorbent. Results also show that the amount of metal ions removed by the graft copolymer, Cs-g-PVP, slightly increases with the increase of the mass of adsorbent from 0.15 g to 0.2 g. The increase of the metal removal, which is directly proportional to the adsorption capacity by the grafted copolymer, with increase of the mass of adsorbent may be due to the increase of the polymer sites available for chelation. 3.4 Metal removal by Cs-g-PVP/f-MWCNTs hybrids Further investigations were performed for copper (II) removal using Cs-g-PVP/f-MWCNTs (containing 3wt% and/or 5wt% by weight) hybrids as metal adsorbent. Removal efficiency (R%) of metal removal by both Cs and Cs/f-MWCNTs are also given for comparison. Adsorbent mass fixed at 0.15 g at pH 7. The results are represented in Figure 5. The results show the % metal removal by the adsorbent, Cs-g-PVP/f-MWCNTs that containing 3wt% of the f-MWCNTs is 98.80 while the hybrid of 5wt% f-MWCNTs has metal removal % of 99.01. The ability of Cs and Cs/f-MWCNTs, containing 3wt% and 5wt% by weight, of f-MWCNTs was also investigated. The results indicated that the removal of Cu (II) ions from the aqueous solution reached 76.38, 84.36 and 89.19 for the three samples respectively. The observed high significant enhancement of metal removal % of these samples confirms the removal efficiency of f-MWCNTs which increases with increasing of its mass. This may be due to the presence of more negatively charged oxygen-containing groups on the oxidized or functionalized form of MWCNTs that have the affinity to attract the copper cations from the aqueous solutions [27]. The incorporation of Cu(II) in Cs-g-PVP and Cs-g-PVP/f-MWCNTs 5wt% was confirmed by SEM analysis, Figure 6 (a,c). Figure 6 (a) showed the presence of copper metal ions on the Cs-g-PVP polymeric surface that appeared as bright spots. Figure 6 (c) shows the SEM image of the as-prepared Cs-g-PVP/f-MWCNTs 5wt% after Cu(II) ions adsorption process. In figure 6 (c) shows that f-MWCNTs appeared as sequestered within regions of chitosan-g-PVP that probably considered as the more hydrophobic phase on the polymeric hybrid. The EDX profile showed peaks for C, N, O and Cu as elemental constituents of the grafted copolymer, Cs-g-PVP and Cs-g-PVP/f-MWCNTs after adsorption of Cu(II) (Figure 6b,d). In EDX, the chemical compositions of Cs-g-PVP/Cu in weight% showed (C, N, O and Cu) was found (57.2 wt%, 5.4 wt%, 25.4 w% and 12.0 wt%) (Figure 6c). However, the chemical compositions of Cs-g-PVP/f-MWCNTs/Cu showed (C, N, O and Cu) was estimated to be (56.1 wt%, 5.2 wt%, 26.5 w% and 12.1 wt%) (Figure 6d). Also mapping of each element in Cs-g-PVP/f-MWCNTs/Cu sample was represented in figure 6e. Thus, these results are confirming that the as prepared Cs-g-PVP and Cs-g-PVP/f-MWCNTs was an efficient material for Cu-adsorption in aqueous solutions. Antibacterial activity The antimicrobial activity of chitosan (Cs), chitosan grafted copolymer (Cs-g-PVP) and two grafted copolymers/f-MWCNTs hybrids (Cs-g-PVP/f-MWCNTs hybrids that containing 3wt% and 5wt% by weight of the MWCNTs) were evaluated against the gram +ve bacteria ( B . Subtitles , St . aurous and St . faecalis ) and the gram -ve bacterial strains ( E . coli , N . gonorrhoeae and P . aeruginosa ) that isolated from animal origin. Agar disk diffusion method was used for the determination of the preliminary antibacterial and Ampicillin was used as reference antibacterial drugs. All of the investigated samples showed, in vitro, antibacterial activity against the tested microorganisms. The results of antibacterial activity of the samples under investigation using inhibition zone method are listed in Tables 2. The results showed that when compared to pristine chitosan, Cs-g-PVP had improved antibacterial activity against all strains of gram-positive and gram-negative bacteria. As a result, Cs has antibacterial efficacy against both types of bacterial strains in terms of inhibition zone diameter. The inhibition zone caused by Cs against the gram +ve bacteria ( B . Subtitles , St . aurous and St . faecalis ) are 13, 15 and 12 with efficiencies of 65, 83 and 67%, respectively with respect to the reference drug. On the other hand, the antibacterial activity of by the effect of Cs against the gram -ve bacterial strains ( E . coli , N . gonorrhoeae and P . aeruginosa ) are 14, 11 and 12 with efficiencies of 64, 55 and 71%, respectively when compared to the standard reference antibacterial drug. The insertion of 4-vinylpyridine (4-VP) as blocks via grafting copolymerization with Cs yielding Cs-g-PVP improved the antibacterial activity of this grafted copolymer against all tested microbes, according to the results of Table 2. In comparison to the reference drug, the antibacterial efficiency for gram +ve bacteria ( B . Subtitles , St . aurous , and St . faecalis ) were 85, 94, and 83, respectively. The antibacterial activity of Cs-g-PVP against the gram -ve bacterial strains ( E . coli , N . gonorrhoeae and P . aeruginosa ) reached 86, 85 and 94%, respectively with respect to the reference antibacterial drug. As a result, the Cs-g-PVP exhibit better efficiency against G -ve bacterial strains than the G +v kinds, according to the given results. These results could be explained by the electrostatic interaction between positively charged chitosan molecules and negatively charged microbial cell membranes, which is the first proposed accepted mechanism for chitosan antibacterial activity [40]. The second predicted action mechanism is chitosan's binding to microbe DNA, which results in mRNA and protein synthesis suppression in the nuclei of bacteria due to chitosan penetration. [41]. Based on the well-known biological properties of nitrogen containing six membered aromatic heterocyclic compounds and their derivatives [42], the observed increased antibacterial activity of Cs-g-PVP can be attributed to the PVP blocks in the grafted copolymeric chains. Additionally, the hydrophobic character of 4-VP in the copolymer chains increases the density of positive charges on the system, which may favor microbial cell attachment to the antibacterial system. As a result, 4-VP-based polymers or copolymers are intriguing materials with a variety of uses, including antibacterial materials [43-44]. Despite its well-known antibacterial properties, applications of Cs are limited due to undesirable properties such as low solubility and chemical stability [45-47]. As a result, various modifications or the addition of reinforcement materials may give rise to improvement to the physicochemical properties of chitosan, allowing it to be used in a wider range of applications. Multiwalled carbon nanotubes (MWCNTs) have thus been proposed as an excellent material to utilize as inorganic fillers for reinforcing or toughening polymeric materials [48], in addition to the grafting of 4-VP onto chitosan performance. Two samples of Cs-g-PVP containing 3 and 5% by weight of MWCNTs were functionalized as stated in the experimental section, affording two hybrids of Cs-g-PVP/f-MWCNTs for testing their biological activity. Table 2 shows the antibacterial activity of the two hybrids against the bacterial strains that were examined. When compared to either chitosan or the reference drug, the results showed that the two hybrids had much higher antibacterial efficacy against both types of bacteria, G +ve and G -ve bacteria. Antibacterial activity of the hybrid containing 3% by weight of f-MWCNTs against G +ve bacterial strains ( B . Subtitles , St . aureus , and St . faecalis ) was 95, 106, and 94 percent, respectively, as compared to the conventional drug. In comparison to the reference drug, the obtained antibacterial activity of the same sample against G -ve bacteria (E. coli, N. gonorrhoeae, and P. aeruginosa) was 114, 110, and 106 respectively. The antibacterial activity effectiveness of the other hybrid, which contained 5wt% by weight of f-MWCNTs, was the highest of the investigated samples. In comparison to the reference antibacterial drug, the inhibitory effect of this hybrid revealed inhibition zones of 20, 21, and 17 mm, respectively, with efficiency of 100, 117, and 94 % against G +ve bacteria ( B . Subtitles , St . aurous , and St . faecalis ). When compared to the reference drug, the examined hybrid recorded inhibitory zones of 26, 24 and 21 mm for the G -ve bacterial strains ( E . coli , N . gonorrhoeae , and P . aeruginosa ), with efficiencies of 118, 120, and 124 %, respectively. The presence of f-MWCNTs in the tested samples is responsible for the observed high antibacterial activity of the two hybrids. MWCNTs have been shown to have strong inhibitory effects on a variety of bacteria in previous work [49]. All postulated mechanisms to explain the bactericidal effect of CNTs in general are not fully known, and there are numerous factors that influence its antibacterial action. The diameter, electrical structure, residual catalyst, length, surface functional group, and other parameters are among them. [50]. In terms of the functionalized MWCNTs employed in this investigation, it has been noted that functionalization is a good way to improve their dispersion in different matrices while also increasing biocompatibility and lowering toxicity in human cells [51]. The optical density of E. coli was significantly reduced when amine or carboxyl moieties were added to MWCNT. According to certain observations, the functionalized carboxylated MWCNTs increased membrane roughness and hydrophilicity, which made them more resistant to bacterial adherence. These findings suggested that f-MWCNT surfaces could be used in the manufacture of medical devices and biomedical applications [52-53]. The incorporation of MWCNTs or f-MWCNTs into chitosan or other synthetic polymers to obtain potentially helpful antibacterial surfaces against Gram-positive and Gram-negative bacteria has been investigated. This could lead to the development of unique physicochemical properties for these polymeric substrates, as well as the prospect of using these composites in a variety of biological applications such as tissue engineering, biosensing, wound dressing, and drug administration [54-55]. Figure 7 illustrates the antibacterial efficiency of the investigated samples with respect to the standard reference drug. Table 2 : The antimicrobial activities of the investigated samples against some G +ve and G -ve bacterial strains Sample Inhibition zone diameter (mm/mg sample) Bacillus Subtitles Staphylococcus aurous Streptococcus faecalis Escherichia coli Neisseria gonorrhea Pseudomonas gonorrhoeae G+ve G-ve DMSO 0.0 0.0 0.0 0.0 0.0 0.0 Ampicillin (100µg/mL) 20 18 18 22 20 17 Cs 13 15 12 14 11 12 Cs-g-PVP Cs-g-PVP/MWCNTs (3%) Cs-g-PVP/MWCNTs (5%) 17 19 20 17 19 21 15 17 17 19 25 26 17 22 24 16 18 21 Conclusions In this study, it was investigated that the catalytic performance of Cs-g-PVP and Cs-g-PVP/f-MWCNTs hybrids was explored in the batch adsorption of Cu(II) in aqueous solutions as simulated wastewater. The results revealed that upon conjugation of f-MWCNTs with Cs-g-PVP, a covalent integration between f-MWCNTs and Cs-g-PVP have been accomplished. The addition of f-MWCNTs to Cs-g-PVP copolymer enhanced the thermal and chemical stability of the polymeric materials because f-MWCNTs possess high tensile strengths, and are ultra-light weight. The study was extended for testing the bioactivity of the as-prepared samples. It was revealed that Cs-g-PVP/f-MWCNTs, having 5% by weight of the f-MWCNTs, exhibited the highest antibacterial activity. The presented polymeric hybrids can be used in wastewater treatment applications for Cu(II) removal and inhibition the growth of bacteria in aqueous solution. Declarations Conflicts of interest The authors have declared no conflict of interest. Acknowledgments The authors acknowledge STDF (Egypt) for their valuable support through research project fund (project ID 27777). DATA AVAILABILITY STATEMENT - All data generated or analysed during this study are included in this published article [and its supplementary information files] References Ahlafi H, Moussout H, Boukhlifi F, Echetna M, Bennani MN, Sliman SM. Kinetics of N-Deacetylation of Chitin Extracted from Shrimp Shells Collected from Coastal Area of Morocco. Medit J of Chem . 2013; 2, 503-513. Varma AJ, Deshpande SV, Kennedy JF. Metal complexation by chitosan and its derivatives: a review. Carbohydr Polym . 2004; 55, 77–93. Ravi Kumar MNV, Muzzarelli RAA, Muzzarelli C, Sashiwa H, Domb AJ. Chem Rev . 2004; 104, 6017–6084. Keyur D, Kevin K, Li J, Davidson PM, Zivanovic S, Meyer H. Nanofibrous chitosan non-woven for filtration applications. Polymer . 2009; 50, 3661–3669. Lin WJ, Chen TD, Liu CW. Synthesis and characterization of lactobionic acid grafted pegylated chitosan and nanoparticle complex application. Polymer . 2009; 50, 4166–4174. Mori T, Murakami M, Okumura M, Kadosawa T, Uede T, Fujinaga T. Mechanism of macrophage activation by chitin derivatives. J of Vet Med Sci 2005; 67, 51–56. Wan NWS, Endud CS, Mayaner R. Removal of copper(II) ions from aqueous solution onto chitosan and cross-linked chitosan beads. React. Funct Polym . 2002; 50, 181–190. Becker T, Schlaak M, Strasdeit H. Adsorption of nickel(II), zinc(II) and cadmium by new chitosan derivatives. React Funct Polym . 2000; 44, 289–298. Sahin M, Kocak N, Arslan G, Ucan HI. Synthesis of Crosslinked Chitosan with Epichlorohydrin Possessing Two Novel Polymeric Ligands and Its Use in Metal Removal. J Inorg Organomet Polym . 2011; 21, 69–80. Yang ZK, Yuan Y. Studies on the synthesis and properties of hydroxyl aza crown ether-grafted chitosan. J Appl Polym Sci . 2001; 82, 1838–1843. Chen S, Wang Y. Study on b-cyclodextrin grafting with chitosan and slow release of its inclusion complex with radioactive iodine. J Appl Polym Sci . 2001; 82, 2414–2421. Jung BO, Kim CH, Choi KS, Lee YM, Kim JJ. Preparation of amphiphilic chitosan and their antimicrobial activities. J Appl Polym Sci . 1999; 72, 1713–1719. Zohuriaan-mehr MJ. Advances in chitin and chitosan modification through graft copolymerization: A comprehensive review. Iran Polym J . 2005; 14, 235-265. Sabaa MW, Elzanaty AM, Abdel-Gawad OF, Arafa EG. Synthesis, characterization and antimicrobial activity of Schiff bases modified chitosan-graft poly(acrylonitrile). Int J of Biol Macromol . 2018; 109, 1280–1291. Yanovska E, Ryabchenko K, Ianovska M, Kichkiruk O, Tertykh V, Davydov V. Adsorption of tungsten, molybdenum, vanadium and chromium from aqueous solutions using pine sawdust-polyaniline composites. Nord Pulp Pap Res J . 2014; 29, 425-433. Yanovska ES, Dadashev AD, Tertykh VA (2009) Inorganic anion–exchanger based on silica with grafted polyhexamethyleneguanidine hydrochloride. Funct Mat 16:105-112. Dadashev AD, Tertykh VA, Yanovska ES, Yanova KV. New approach to synthesis of silica with chemically bound guanidine hydrochloride for preconcentration of metal ions. Am J Anal Chem . 2016; 7, 411-420. Chen Y, Zhao, W, Zhang J. Preparation of 4-vinylpyridine (4VP) resin and its adsorption performance for heavy metal ions. RSC Adv . 2017; 7, 4226–4236. Shaglaeva NS, Baginov DB, Filatova EG, Pozhidaev YuN, Podgorbunskaya TA, Stanevich LM. Adsorbent of Noble Metals, Based on Copolymers of Divinyl Sulfi de and 4-Vinylpyridine. Russ J of Appl Chem. 2019; 92, 92−97. Laganà P, Visalli G, Facciolà A, Ciarello MP, Laganà A, Iannazzo D, Pietro AD. Is the Antibacterial Activity of Multi-Walled Carbon Nanotubes (MWCNTs) Related to Antibiotic Resistance? An Assessment in Clinical Isolates. Int J Environ Res, Public Health . 2021; 18, 9310 Tjong SC, Structural and mechanical properties of polymer nanocomposites. Mat Sci and Eng: R: Reports . 2006; 53, 73–197. Masheane M, Nthunya L, Soraya Malinga S, Nxumalo E, Tobias Barnard T, Sabelo M. Antimicrobial Properties of Chitosan-Alumina/f-MWCNT Nanocomposites. J of Nanotechnol 2016; Article ID 5404529, 8 pages. Kosa SA, Al-Zhrani G, Abdel Salam M. Removal of heavy metals from aqueous solutions by multi-walled carbon nanotubes modified with 8-hydroxyquinoline. Chem Eng J . 2012; 181–182, 159–168. K.V. Harish Prashanth, R.N. Tharanathan, Studies on graft copolymerization of chitosan with synthetic monomers. Carbohydr. Polym . 2003; 54, 343–351. Mohamed RR, Sabaa MW. Chemically Induced Graft Copolymerization of Acrylonitrile onto Carboxymethyl Chitosan and its Modification to Amidoxime Derivative. J Appl Polym Sci . 2010; 116, 413–421. Santangelo S, Messina G, Faggio G, Abdul Rahim SH, Milone C. Effect of sulphuric–nitric acid mixture composition on surface chemistry and structural evolution of liquid-phase oxidized carbon nanotubes. J Raman Spectr . 2012; 43, 1432-1442. 27. Rodríguez C, Leiva E. Enhanced Heavy Metal Removal from Acid Mine Drainage Wastewater Using Double-Oxidized Multiwalled Carbon Nanotubes. Molecules 2019, 25, 111 Jeong JH, Shin KS, Lee JW, Park EJ, Son SY. Analysis of a novel class 1 integron containing metallo-beta-lactamase gene VIM-2 in Pseudomonas aeruginosa. J Microbiol . 2009; 47, 753–759. Kanokwiroon K, Teanpaisan R, Wititsuwannakul D, Hooper AB, Wititsuwannakul R. Mycoses . 2008; 51, 301–307. National Committee for Clinical Laboratory Standards, Reference method for Broth Dilution Antifungal susceptibility testing of Conidium-Forming Filamentous Fungi: proposed guideline M38-A. NCCLS, Wayne, PA, USA. 2002. 31. National Committee for Clinical Laboratory Standards, Method for antifungal disk diffusion susceptibility testing of yeast: proposed guideline M44-P. NCCLS, Wayne, PA, USA.2003. Liebowitz LD, Ashbee HR, Evans EGV, Chong Y, Mallatova N, Zaidi M, Gibbs D. A two-year global evaluation of the susceptibility of Candida species to fluconazole by disk diffusion. Diagn. Microbiol. Infect. Dis . 2001; 40, 27–33. Matar ML, Ostrosky-Zeichner L, Paetznick VL, Rodriguez JR, Chen E, Rex JH. Correlation between E-Test, Disk Diffusion, and Microdilution Methods for Antifungal Susceptibility Testing of Fluconazole and Voriconazole. Antimicrob Agents Chemother . 2003; 47, 1647–1651. Elkholy SS, Khalil KhD, Elsabee MZ. Homogeneous and heterogeneous grafting of 4-vinylpyridine onto chitosan. J Appl Polym Sci . 2006; 99, 3308–3317 Ziegler-Borowska M, Chełminiak D, Kaczmarek H. Thermal stability of magnetic nanoparticles coated by blends of modified chitosan and poly(quaternary ammonium) salt. J Therm Anal Calorim . 2015; 119, 499–506. Zeng L, Qin C, Wang L, Li W. Volatile compounds formed from the pyrolysis of chitosan. Carbohydr Polym . 2011; 83, 1553–1557. Zalloum HM, AL-Qodah Z, MUBARAK MS. Copper Adsorption on Chitosan-Derived Schiff Bases. J of Macromol Sci R, Part A: Pure and Appl Chem . 2009; 46, 46–57. Shafa-Amry NN, Khalili FI, Ebraheem KAK, Mubarak MS. Synthesis and chelation properties of Mannich polymers derived from piperazine and some hydroxy benzaldoximes. React Funct Polym . 2006; 66, 789-794. Bhatt RR, Shah BA, Shah AV. Uptake of heavy metal ions by chelating ion-exchange resin derived from p-hydroxibenzoic acid form aldehyde resorcinol: synthesis, characterization and sorption dynamics. The Malays J of Anal Sci . 2012; 16, 117-133. Feng QL, Wu J, Chem GQ, Cui FZ, Kem TN. A Mechanistic Study of the Antibacterial Effect of Silver Ions on Escherichia coli and Staphylococcus aureus. J Biomed Mater Res . 2000; 52, 662–668. Hadwiger LA, Kendra DF, Fristensky BW, Wagoner W. Chitosan both activates genes in plants and inhibits RNA synthesis in fungi, in: R.A.A. Muzzarelli, C. Jeuniaux, C.W. Gooday (Eds.), in Chitin in Nature and Technol , Plenum Press, New York. 1986; 209–221. Altaf AA, Shahzad A, Gul Z, Rasool N, Badshah A, Lal B, Khan E. A review on the medicinal importance of pyridine derivatives. J of Drug Design and Med Chem . 2015; 29, 1-11. Li Y, Yang MJ, She Y. Humidity sensitive properties of crosslinked and quaternized poly(4-vinylpyridine co-butyl methacrylate). Sens and Actuat B . 2005; 107, 252-257. Li D, He Q, Cui Y, Li J. Fabrication of pH-responsive nanocomposites of gold nanoparticles/poly(4- vinylpyridine). J Chem Mater . 2007; 19, 412-417. Chen S, Wu G, Long D, Liu Y. Preparation, characterization and antibacterial activity of chitosan-Ca3V10O28 complex membrane. Carbohydr Polym . 2006; 64, 92–97. Yadav SK, Mahapatra SS, Yadav MK, Dutta PK. Mechanically robust biocomposite films of chitosan grafted carbon nanotubes via the [2 + 1] cycloaddition of nitrenes. RSC Advances . 2013; 3, 23631–23637. Mi FL, Wu SJ, Lin FM. Adsorption of copper(II) ions by a chitosan-oxalate complex biosorbent. Int J of Biol Macromol . 2015; 72, 136–144. Tjong SC. Structural and mechanical properties of polymer nanocomposites. Materials Science and Engineering: R. Reports . 2006; 53, 73–197. Chen H, Wang B, Gao D, Guan M, Zheng L, Ouyang H, Chai Z, Zhao Y, Feng W. Broad-spectrum antibacterial activity of carbon nanotubes to human gut bacteria. Small . 2013; 9, 2735–2746. Kang S, Herzberg M, Rodrigues DF, Elimelech M. Antibacterial effects of carbon nanotubes: size does matter! Langmuir. 2008; 24, 6409–6413. Upadhyayula VKK, Gadhamshetty V. Appreciating the role of carbon nanotube composites in preventing biofouling and promoting biofilms on material surfaces in environmental engineering: a review. Biotechnol Adv . 2010; 28, 802–816. Kumar S, Bose S, Chatterjee K. Amine-functionalized multiwall carbon nanotubes impart osteo inductive and bactericidal properties in poly(ε-caprolactone) composites. RSC Adv . 2014; 4, 19086–19098. Alizadeh A, Razmjou A, Ghaedi M, Jannesar R. Nanoporous solid-state membranes modified with multi-wall carbon nanotubes with anti-biofouling property. Int J Nanomedicine . 2019; 14, 1669–1685. Nie C, Cheng C, Peng Z, Ma L, He C, Xia Y, Zhao C. (2016). Mussel-inspired coatings on Ag nanoparticle-conjugated carbon nanotubes: bactericidal activity and mammal cell toxicity. J Mater Chem. 2016; B 4, 2749–2756. El-Ghany NAA. Antimicrobial activity of new carboxymethyl chitosan–carbon nanotube biocomposites and their swellability in different pH media. J. Carbohyd. 2017; 36, 31-44. Additional Declarations No competing interests reported. Supplementary Files 11.pdf 1CNOCu.jpg 22.pdf 4CNOCu.jpg 6CNOCu.jpg 8CNO.jpg MR.xlsx View010CK.bmp View010CuK.bmp View010NK.bmp View010OK.bmp Cite Share Download PDF Status: Under Review Version 1 posted Editorial decision: Major revision 12 Jul, 2022 Reviews received at journal 05 Jul, 2022 Reviewers agreed at journal 01 Jul, 2022 Reviewers agreed at journal 20 Jun, 2022 Reviewers invited by journal 17 Jun, 2022 Editor assigned by journal 31 May, 2022 Editor invited by journal 31 May, 2022 Submission checks completed at journal 31 May, 2022 First submitted to journal 09 May, 2022 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. 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02:59:08","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-1640092/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-1640092/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":22377457,"identity":"9b854450-8d35-43c4-b4e7-d094ba588ba4","added_by":"auto","created_at":"2022-06-07 19:05:00","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":56869,"visible":true,"origin":"","legend":"\u003cp\u003eIR spectra of (a) Cs and (b) Cs-g-PVP.\u0026nbsp;\u003c/p\u003e\u003cp\u003e\u003cbr\u003e\u003c/p\u003e","description":"","filename":"1.png","url":"https://assets-eu.researchsquare.com/files/rs-1640092/v1/b220022c137da1e1f4f66180.png"},{"id":22377461,"identity":"79ea48ab-10f0-4a15-9cb5-5803314bb11f","added_by":"auto","created_at":"2022-06-07 19:05:00","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":19120,"visible":true,"origin":"","legend":"\u003cp\u003eThermogram of Cs, Cs-g-PVP, Cs-g-PVP/f-MWCNTs (3wt%) and Cs/f-MWCNTs (5wt%)\u003cstrong\u003e.\u003c/strong\u003e\u003c/p\u003e\u003cp\u003e\u003cbr\u003e\u003c/p\u003e","description":"","filename":"2.png","url":"https://assets-eu.researchsquare.com/files/rs-1640092/v1/934a8c9b6bc88420f3d88e1a.png"},{"id":22377809,"identity":"ce34be77-284f-4e36-9f42-5fe71efbde5d","added_by":"auto","created_at":"2022-06-07 19:10:00","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":367456,"visible":true,"origin":"","legend":"\u003cp\u003eSEM images of (a) Cs, (b) Cs-g-PVP, (c) Cs-g-PVP/f-MWCNT 3wt%, and Cs-g-PVP/f-MWCNT 5wt%.\u0026nbsp;\u003c/p\u003e\u003cp\u003e\u003cbr\u003e\u003c/p\u003e","description":"","filename":"3.png","url":"https://assets-eu.researchsquare.com/files/rs-1640092/v1/29e892d701a3159af7a057e4.png"},{"id":22378706,"identity":"b67dd445-70e7-40b6-a58c-e70b3cbfa784","added_by":"auto","created_at":"2022-06-07 19:20:01","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":191165,"visible":true,"origin":"","legend":"\u003cp\u003eMetal removal % as a function of pH and adsorbent masses.\u003c/p\u003e","description":"","filename":"4.png","url":"https://assets-eu.researchsquare.com/files/rs-1640092/v1/4114f64b2384c344d007aa99.png"},{"id":22377458,"identity":"aa835479-57ce-463d-8b72-3e21d3a67b9c","added_by":"auto","created_at":"2022-06-07 19:05:00","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":12702,"visible":true,"origin":"","legend":"\u003cp\u003eRemoval efficiency % by Cs, Cs-g-PVP and Cs-g-PVP/f-MWCNTs hybrids containing 3wt% and 5wt% by weight of f-MWCNTs using 0.15 g adsorbent at pH 7.\u003c/p\u003e\u003cp\u003e\u003cbr\u003e\u003c/p\u003e","description":"","filename":"5.png","url":"https://assets-eu.researchsquare.com/files/rs-1640092/v1/6ab06423ae9724a7209af1e4.png"},{"id":22378705,"identity":"2e1c4d6f-4901-445d-ad00-0e113cfde8f7","added_by":"auto","created_at":"2022-06-07 19:20:00","extension":"png","order_by":6,"title":"Figure 6","display":"","copyAsset":false,"role":"figure","size":342517,"visible":true,"origin":"","legend":"\u003cp\u003e(a) SEM image and (b) EDX profile of Cs-g-PVP/CuCl\u003csub\u003e2\u003c/sub\u003e; (c) SEM of Cs-g-PVP/MWCNTs/CuCl\u003csub\u003e2\u003c/sub\u003e; (d) EDX profile of Cs-g-PVP/f-MWCNTs/CuCl\u003csub\u003e2\u003c/sub\u003e (e) EDX mapping analysis of elemental constitutes of Cs-g-PVC/f-MWCNTs/CuCl\u003csub\u003e2\u003c/sub\u003e 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19:10:01","extension":"bmp","order_by":10,"title":"","display":"","copyAsset":false,"role":"supplement","size":60038,"visible":true,"origin":"","legend":"","description":"","filename":"View010NK.bmp","url":"https://assets-eu.researchsquare.com/files/rs-1640092/v1/b3d82b5734dcb7f4b3da1087.bmp"},{"id":22377818,"identity":"a8015e0f-d084-4ad7-a1bd-5379586daf51","added_by":"auto","created_at":"2022-06-07 19:10:01","extension":"bmp","order_by":11,"title":"","display":"","copyAsset":false,"role":"supplement","size":60038,"visible":true,"origin":"","legend":"","description":"","filename":"View010OK.bmp","url":"https://assets-eu.researchsquare.com/files/rs-1640092/v1/25b27babc0b662843211424e.bmp"}],"financialInterests":"No competing interests reported.","formattedTitle":"Facile Synthesis of chitosan-g-PVP/f-MWCNTs for application in Cu(II) ions removal and for bacterial growth inhibition in aqueous solutions","fulltext":[{"header":"Introduction","content":"\u003cp\u003eChitosan is a natural biopolymer with a linear polysaccharide structure and is found as an N-deacetylated chitin derivative [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e]. Chitosan possesses a number of desirable characteristics, including biocompatibility, biodegradability, antibacterial activity, non-toxicity, and a variety of other physical features [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e]. As a result, this essential natural biopolymer may be applied widely in a variety of disciplines, including medicine, cosmetics, food processing, waste water treatment, and environmental protection [\u003cspan additionalcitationids=\"CR4\" citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e]. Previous work showed that Cs has the ability to inhibit the growth of many species of microbes in dilute acidic environment because it carries positive charges that can interact with the negatively charged molecular cell membranes of microorganisms. These microorganisms' molecular cell membranes may rupture or be damaged as a result of this electrostatic contact [\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e]. Chitosan adsorbs metal ions and removes metallic contaminants from wastewaters. As a result of the presence of both amine and hydroxyl groups as chelating sites for metal ions, chitosan is regarded to be a suitable chelating agent [\u003cspan additionalcitationids=\"CR8\" citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e]. Chemical grafting of chitosan improves its chelating characteristics [\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e], antibacterial activity [\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e], and other features for a variety of applications. Chitosan graft copolymerization is a significant modification approach for affording new and various molecular designs of good types of hybrid materials containing bio- and synthetic polymeric components [\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e]. Cs-g-PAN is obtained by graft copolymerizing chitosan with acrylonitrile utilizing a free radical copolymerization procedure with potassium persulfate as the initiator. Some positive and negative gram bacterial strains demonstrated good antibacterial activities when grafted chitosan was used [\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e]. Nitrogen-containing polymers or copolymers, such as polyaniline and various polyhexamethylene guanidine derivatives, have been shown to have high metal adsorption affinities [\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e]. Heavy metal removal was achieved using a homopolymer and a few copolymers containing 4-vinylpyridine [\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e]. 4-VP has also been grafted onto polystyrene or copolymerized with divinyl sulfide to produce a resin with good metal adsorption characteristics [\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e]. New materials that can withstand the microbiological growth of some pathogens in the hospital environment have recently been tested. Using both native and functionalized versions of MWCNTs at concentrations of 50 and 100 g/ ml, different dosages of MWCNTs on the inhibitory effect were determined [\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e]. MWCNTs have additional advantages and potential features for use as inorganic fillers in polymeric substrate reinforcement [\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e]. Alumina and functionalized MWCNTs were incorporated into chitosan to increase certain of its physicochemical qualities, such as thermal stability, while reducing the chitosan's swell ability and solubility. Cs-alumina/f-MWCNTs nanocomposites have an antibacterial effect comparable to pure chitosan. As a result, even at low pH and high temperatures, these produced Cs-alumina/f-MWCNTs could be employed as effective antibacterial agents [\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eCu (II), Cd (II), Pb (II), and Zn (II) were all removed from aqueous solutions using multiwalled carbon nanotubes that had been treated with 8-hydroxyquinoline. The effects of several parameters on metal adsorption by MWCNTs, such as dosages, metal ion concentrations, temperature, and pH values, were studied [\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e]. The development and characterization of a chitosan grafted-4-vinylpyridine copolymer to be used as a metal removal and antibacterial agent from aqueous solution were the focus of this work.\u003c/p\u003e \u003cp\u003eThis research went on to look at grafting two different weight percentages of f-MWCNTs into the grafted copolymer to create two hybrids and see how they affected metal removal and bacterial growth suppression in aqueous solution.\u003c/p\u003e "},{"header":"Experimental","content":"\u003cp\u003e\u003cstrong\u003e2.1. Materials\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eChitosan (MW 100\u0026ndash; 300 kDa, 82% degree of deacetylation) was purchased from Across Organics, Belgium. Potassium persulfate (KPS), CuCl\u003csub\u003e2\u003c/sub\u003e and 4-vinylpyridine were supplied from Sigma Aldrich. MWCNTs were purchased from Sigma-Aldrich Company. All other fine chemicals were of fine grades and all solvents were distilled before use. \u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e2.2. Characterization techniques and analysis\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e2.2.1. FTIR Spectroscopy\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u0026nbsp;FTIR spectra were recorded on Shimadzu IR-Spectrometer (FTIR 8201) Japan, at room temperature within the wavenumber range of 4000 to 400 cm\u0026minus;1 using KBr discs.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e2.2.2. Thermogravimetric Analysis (TGA)\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThermogravimetric analysis was carried out on TGA-50H thermogravimetric analyzer, Shimadzu, Japan. Samples were heated up to 800\u0026nbsp;\u003csup\u003e∘\u003c/sup\u003eC in a platinum pan with a heating rate of 10∘\u0026nbsp;C/min, in N\u003csub\u003e2\u003c/sub\u003e atmosphere of flow rate 25 mL/min.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e2.2.3. Scanning Electronic Microscopy (SEM)\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe dry samples were spread on a conducting adhesive tape, pasted on a metallic stub. The morphologies of the tested samples were investigated and imaged with scanning electron microscope (SEM) (QUANTA FEG 250 ESEM, USA). This was accompanied by energy dispersive X-ray spectroscopy (EDAX AMETEK Inc.; Mahwah, NJ, USA) at an acceleration voltage of 15 kV. The films were fixed on the surface of a sticky tape\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e2.3. Preparation of\u003c/strong\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003cstrong\u003echitosan graft-poly(4-vinylpyridine)\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eChitosan solution was prepared by dissolving 0.8 g of chitosan in 100 ml of 1% aqueous acetic acid solution and was placed in a flat bottomed three necked flask with stirring and the reaction temperature was raised to 60 \u003csup\u003eo\u003c/sup\u003eC. Then, nitrogen gas was purged into the reaction mixture at a constant temperature (ca ~60 \u003csup\u003e◦\u003c/sup\u003eC) with continuous stirring. Freshly prepared potassium persulfate solution (3\u0026times;10\u003csup\u003e\u0026minus;2\u003c/sup\u003e mol/L) was added and then (2 mol/L) of 4-vinylpyridine was subsequently added by dropwise addition. The reaction was conducted for 2 h with stirring and continued for another 15 min at room temperature. Then the reaction product was precipitated out with 10% of (NaOH/MeOH) mixture, filtered, and dried. It was subjected to Soxhlet extraction for 8\u0026ndash;12 h using N,N-dimethylformamide (DMF) to solubilize and remove any homopolymer [24]. The preparation of the chitosan grafted copolymer was illustrated in Scheme 1.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eThe graft yield (G%), the grafting efficiency (GE%) and the amount of homopolymer (H%) formed were calculated according to the following equation\u003c/p\u003e\n\u003cp\u003eGraft yield (G%) = [(W\u003csub\u003e1\u003c/sub\u003e \u0026minus;W\u003csub\u003e0\u003c/sub\u003e)/W\u003csub\u003e0\u003c/sub\u003e] \u0026times; 100\u003c/p\u003e\n\u003cp\u003eGrafting efficiency (GE%) = (W\u003csub\u003e1\u003c/sub\u003e/W\u003csub\u003e2\u003c/sub\u003e) \u0026times; 100\u003c/p\u003e\n\u003cp\u003eWhere W\u003csub\u003e0\u003c/sub\u003e, W\u003csub\u003e1\u003c/sub\u003e are the weights of initial matrix and grafted matrix (i.e), weight of the product after extraction, respectively [25].\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e2.4. Preparation of functionalized and Cs-g-PVP/MWCNTs hybrids\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe multi-walled carbon nanotubes (MWCNTs) were purchased from Sigma-Aldrich Company. Functionalization of\u0026nbsp;MWCNTs\u0026nbsp;was performed\u0026nbsp;as\u0026nbsp;reported before [26-27]. 0.5 g of MWCNTs was dispersed in 100 mL 65% nitric acid at 120\u003csup\u003eo\u003c/sup\u003eC for 15h under magnetic stirring. The obtained solution was then washed with water several times to neutrality, filtered and finally dried at 80 ᵒC for 12h to obtain the functionalized MWCNTs, f-MWCNTs, samples which are ready now for use. \u0026nbsp;To a predetermined weight of the grafted copolymer Cs-g-PVP in 20 mL of distilled water, f-MWCNTs (3wt% or 5wt% by weight of the grafted copolymer) was added and left for 30 min under magnetic stirring and then sonicated for another 30 min to obtain Cs-g-PVC/MWCNTs hybrids. A schematic representation was given to explain the formation of Cs-g-PVP/f-MWCNT hybrid, scheme 2.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e2.5. Metal ion adsorption measurements using a batch method\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe batch adsorption\u0026nbsp;experiments were performed by taking 20\u0026nbsp;mL of metal ion solution with a concentration of 5x10\u003csup\u003e-3\u003c/sup\u003e mol/L and pH (4, 7 and 9) in the Erlenmeyer flask; The solutions pH was adjusted using acetic acid/sodium acetate (AcOH/NaOAc) and NH\u003csub\u003e4\u003c/sub\u003eOH/NH\u003csub\u003e4\u003c/sub\u003eCl buffer solutions to study the metal uptake at both the alkaline and the acidic mediums (pH 4 and 9) respectively. A predetermined weight of the prepared adsorbent copolymer (0.05, 0.10, 0.15 and 0.20 g) was added and the adsorption equilibrium was reached after 50 min of magnetic stirring at 25 ᵒC. After separation of the phases by centrifugation (10,000 rpm), the amount of metal-ion uptake of the polymers was determined by using atomic absorption spectrometry (AAS). \u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e2.6. Antibacterial activity\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAntibacterial activity of the tested samples was evaluated using a modified Kirby-Bauer disc diffusion method [28]. Briefly, 100mL of the test bacteria were grown in 10 mL of fresh media until they reached a count of approximately 108 cells/mL for bacteria [29]. 100 mL of microbial suspension were spread onto agar plates corresponding to the broth in which they were maintained. Isolated colonies of each organism, that might be playing a pathogenic role, should be selected from primary agar plates. They were examined for susceptibility by disc diffusion method [30-31]. Of the many media available, National Committee of Clinical Laboratory Standards (NCCLS) recommends Mueller-Hinton agar due to its good results in batch to\u0026ndash;batch reproducibility. Antibacterial activity of the prepared hydrogels was investigated against three types of Gram +ve bacteria (\u003cem\u003eStaphylococcus aurous\u003c/em\u003e, \u003cem\u003eBacillus Subtitles\u003c/em\u003e and \u003cem\u003eStreptococcus faecalis\u003c/em\u003e) and three Gram \u0026ndash;ve bacteria (\u003cem\u003eEscherichia coli\u003c/em\u003e, \u003cem\u003ePseudomonas aeruginosa\u0026nbsp;\u003c/em\u003eand \u003cem\u003eNeisseria gonorrhoeae\u003c/em\u003e. Plates are inoculated with bacteria at 35\u0026ndash;37ᵒC for 24\u0026ndash;48 h [28]. Standard discs of Ampicillin (Antibacterial agent) have served as positive controls for antibacterial activity but filter discs impregnated with 10mL of solvent (distilled water, chloroform, DMSO) have been used as a negative control. The agar used is Meuller-Hinton agar that is rigorously tested for composition and pH. Further, the depth of the agar in the plate is considered to be a factor in the disc diffusion method. This method is well documented and standard inhibition zones have been determined for susceptible and resistant values. Blank paper discs (Schleicher and Schuell, Spain) with a diameter of 8.0 mm were impregnated with 10 m of tested concentration of the stock solutions. When a filter paper disc, impregnated with a tested chemical- is placed on agar, the chemical will diffuse from the disc into the agar. This diffusion will place the chemical on the agar only around the disc. The size of the area of chemical in filtration around the disc was determined by solubility of the chemical and its molecular size. If an organism is placed on the agar, it will not grow around the disc if it is susceptible to the chemical. This area of no growth around the disc is known as a \u0026ldquo;zone of Inhibition\u0026rdquo; or \u0026ldquo;clear zone.\u0026rdquo; For the disc diffusion, the zone diameters were measured with slipping calipers of the NCCLS [29]. Agar based methods such as E-test and disc diffusion are considered to be good alternatives because they are simpler and faster than broth-based methods [32-33].\u0026nbsp;\u003c/p\u003e"},{"header":"Results And Discussion","content":"\u003cp\u003eCs-g-PVP was obtained by grafting 4-vinylpyridine copolymerization onto chitosan as described in the experimental section. According to the given equations in the experimental section, the grafting (G %) and grafting efficiencies (GE%) were calculated to be 92 and 236 %, respectively. FTIR spectroscopic analysis was used to confirm the grafted copolymer that had been formed. In addition, Cs-g-PVP/f-MWCNTs hybrids containing 3wt% and 5wt% of f-MWCNTs were also prepared. The affinity of the obtained grafted copolymer and its hybrids for copper ions adsorption was determined using batch adsorption method and metal removal % was determined using atomic absorption spectrometry (AAS). The effect of pH and the adsorbent mass on % metal removal was studied. Thermal stability of the copolymer, Cs-g-PVP and the two hybrids\u0026nbsp;was determined via thermal gravimetric analysis, TGA, whereas scanning electron microscopy was applied for morphological studies of these samples. Antimicrobial activity of the all-prepared samples was evaluated.\u003c/p\u003e\n\u003cp\u003e\u0026nbsp;\u003cstrong\u003e3.1. FTIR analysis\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe evidence of the formation of Cs-g-PVP was achieved by FTIR analysis. Figure 1 (a,b) represented the FTIR\u0026nbsp;spectrum of both Cs and Cs-g-PVP. It was clearly shown a strong IR band at 3433 cm\u003csup\u003e-1\u003c/sup\u003e which should be assigned to the symmetrical stretching vibration of the OH groups, the extension vibration of the NH\u003csub\u003e2\u003c/sub\u003e, and the intermolecular hydrogen bonds of the polysaccharide. There are also two IR peaks appeared at 2918 and 2851 cm\u003csup\u003e-1\u003c/sup\u003e that may be due to the aliphatic CH\u003csub\u003e2\u003c/sub\u003e and CH. The C-O absorption peak of the hydroxyl group was observed to 1068 cm\u003csup\u003e-1\u003c/sup\u003e. In Figure 1, the grafting of 4-vinylpyridine onto chitosan was confirmed by the presence of C=N groups band at about 2120 cm\u003csup\u003e\u0026minus;1\u003c/sup\u003e from the poly 4-vinylpyridine chains and the \u0026ndash;CH bending of the aromatic ring of the vinyl pyridine that appeared around 746, 821, and 1601 cm\u003csup\u003e-1\u003c/sup\u003e and this is very indicative to the grafting copolymerization of vinyl pyridine moiety with chitosan [34].\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e3.2. Thermogravimetric analysis\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eTGA analysis of Cs, Cs-g-PVP, Cs/f-MWCNTs and Cs-g-PVP/f-MWCNTs hybrid that containing 5% by weight of f-MWCNTs are shown in Figure 2. The thermogram revealed that Cs-g-PVP has a relative higher thermal stability than Cs in terms of both initial decomposition temperature (IDT) and residual weight below 500 \u003csup\u003eo\u003c/sup\u003eC,. The effect of f-MWCNTs (5wt% by weight) in both Cs and the grafted copolymer was investigated, and the results revealed that both Cs/f-MWCNTs and Cs-g-PVP/f-MWCNTs hybrids had significant higher thermal stability than either Cs or Cs-g-PVP. For example, at 250 ᵒC, the recorded weight loss of Cs, Cs-g-PVP, Cs/MWCNTs and Cs-g-PVP/MWCNTs hybrids are 27%, 31%, 13% and 10% respectively. The improved thermal stability of the two hybrids was found to be so significant at the decomposition temperature of 300 \u003csup\u003eo\u003c/sup\u003eC. The weight loss of Cs/f-MWCNTs and Cs-g-PVP/f-MWCNTs hybrids are 21% and 11% whereas the percentages weight loss of both Cs and Cs-g-PVP are 57 and 49 respectively. Cs and Cs-g-PVP hybrids lost 66% and 57% of their weight respectively, at 400 \u003csup\u003eo\u003c/sup\u003eC while Cs/f-MWCNTs and Cs-g-PVP/f-MWCNT hybrids lost 47% and 43% of their weight at the same temperature. At 515 \u003csup\u003eo\u003c/sup\u003eC, both Cs/f-MWCNTs and Cs-g-PVP/f-MWCNTs hybrids have almost the same weight loss of about 58 %, whereas Cs and Cs-g-PVP exhibited weight loss of 88 and 75 %, respectively. The thermal properties of the samples under investigation are shown in Table1. It showed the residual weights of the tested samples at 400 and 500 ᵒC, as well as the temperatures at which they lost 10 and 50% of their weight. The observed weight loss in the early stages of degradation for all investigated samples might be attributed to any attached water residues or volatiles being released from the polymeric chains. The observed degradation of Cs could be due to dehydration and depolymerization of Cs units, which increases as the polymeric network structure proceeds [35-36]. The presence of a PVP block in the grafted copolymer, with its better thermal stability due to the presence of the aromatic ring in the chemical structure of PVP, could explain the higher thermal stability of Cs-g-PVP than Cs. It was demonstrated that the thermal stability of Cs and the grafted copolymeric matrix of Cs-g-PVP was improved by incorporation f-MWCNTs in 3wt% and 5wt% by weight, resulting in two hybrids. The barrier function of the f-MWCNTs may be responsible for this improved thermal stability.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eTable 1\u003c/strong\u003e. Thermal properties of various investigated samples\u0026nbsp;\u003c/p\u003e\n\u003ctable border=\"0\" cellpadding=\"0\" cellspacing=\"0\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"47.71689497716895%\"\u003e\n \u003cp\u003eSample\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"13.013698630136986%\"\u003e\n \u003cp\u003eT\u003csub\u003e10%\u003c/sub\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"13.013698630136986%\"\u003e\n \u003cp\u003eT\u003csub\u003e50%\u003c/sub\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"13.013698630136986%\"\u003e\n \u003cp\u003eR\u003csub\u003e400%\u003c/sub\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"13.242009132420092%\"\u003e\n \u003cp\u003eR\u003csub\u003e500%\u003c/sub\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"47.71689497716895%\"\u003e\n \u003cp\u003eCs\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"13.013698630136986%\"\u003e\n \u003cp\u003e53\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"13.013698630136986%\"\u003e\n \u003cp\u003e277\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"13.013698630136986%\"\u003e\n \u003cp\u003e34\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"13.242009132420092%\"\u003e\n \u003cp\u003e13\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"47.71689497716895%\"\u003e\n \u003cp\u003eCs-g-PVP\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"13.013698630136986%\"\u003e\n \u003cp\u003e207\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"13.013698630136986%\"\u003e\n \u003cp\u003e310\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"13.013698630136986%\"\u003e\n \u003cp\u003e43\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"13.242009132420092%\"\u003e\n \u003cp\u003e26\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"47.71689497716895%\"\u003e\n \u003cp\u003eCs/MWCNTs (3wt%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"13.013698630136986%\"\u003e\n \u003cp\u003e213\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"13.013698630136986%\"\u003e\n \u003cp\u003e423\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"13.013698630136986%\"\u003e\n \u003cp\u003e53\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"13.242009132420092%\"\u003e\n \u003cp\u003e43\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"47.71689497716895%\"\u003e\n \u003cp\u003eCs-g-PVP/ MWCNTs (5wt%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"13.013698630136986%\"\u003e\n \u003cp\u003e229\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"13.013698630136986%\"\u003e\n \u003cp\u003e436\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"13.013698630136986%\"\u003e\n \u003cp\u003e57\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"13.242009132420092%\"\u003e\n \u003cp\u003e43\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e\u003cstrong\u003e\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\u003e\u003cstrong\u003e3.3. Scanning electron microscopy \u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eSEM images of Cs and Cs-g-PVP Cs-g-PVP/f-MWCNTs (I and II) hybrids and are shown in Figure 3 (a-d). The morphology of the chitosan was depicted in Figure 3 (a). Upon graphitization of Cs with 4-VP, to obtain Cs-g-PVP, an obvious change in the surface morphology of the grafted chitosan that gave a proof for conjugation of 4-VP blocks in the copolymer chains and this is represented in Figure 3 (b). By treating chitosan grafted- 4-vinylpyridine copolymer with f-MWCNTs (3wt% and 5wt%,). It was apparently shown that the functionalized MWCNTs \u0026nbsp;are bonded to chitosan-g-PVP. The f-MWCNTs was appeared in micron length sizes with distinct agglomeration in the surface of the formed polymeric composite. \u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e3.4 Batch adsorption studies\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eBatch adsorption experiments were performed using Cs-g-PVP, Cs-g-PVP/f-MWCNTs hybrid (containing 3wt% and 5wt% by weight) as polymeric adsorbent according to the method described before in the experimental part. Cs and Cs/f-MWCNTs was also examined as metal adsorbent for comparison. Metal solutions with concentration of 5x10\u003csup\u003e-3\u003c/sup\u003e mol/L of CuCl\u003csub\u003e2\u003c/sub\u003e.\u0026nbsp;2H\u003csub\u003e2\u003c/sub\u003eO at pH (4, 7 and 9), adsorbent copolymer (0.05, 0.10, 0.15 and 0.20 g) were applied and the effect of both pH and copolymer mass will be discussed.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e3.4.1. Effect of pH\u003c/strong\u003e \u003cstrong\u003eand adsorbent mass on metal removal by the graft copolymers Cs-g-PVP\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe results of copper (II) uptake by the produced Cs-g-PVP as a function of pH and mass adsorbent are shown in Figure 4. The applied masses of the grafted copolymer as adsorbent are; 0.05, 0.10, 0.15 and 0.20 g whereas the working pH values are 4, 7 and 9. The results show that when different masses of adsorbent were used, the metal removal % increase as the pH increase from 4 to 7 [37], but there was a considerable reduction at pH 9. Figure 4 indicates that both the pH and the adsorbent mass have an impact on the metal removal % of copper (II) from aqueous solutions. For adsorbent masses of 0.05, 0.10, 0.15, and 0.20 g, the metal removal % was 21.08, 26.22, 28.75, and 29.17 at pH 4. At pH 7, the percentages of metal removal for the same copolymer masses are 35.54, 38.38, 39.32, and 40.09. It is noticed that at pH 9 these percentages are reduced to be 30.27, 32.17, 34.59 and 35.12. The increase of metal removal by the increase of pH from 4 to 7 may be due to the remarkable hydrolysis of the copper (II) ions at higher pH and this may compete with polymer chelation process. In all cases, the pH highly affects the oxygen atoms of OH or the lone pairs of electrons on the nitrogen atoms of the adsorbent. At higher values of pH, the OH may lose its proton and bear a negative charge while the nitrogen atom lone pair will be more available for binding to metal ions and this increase the attraction of metallic ions onto the surface of adsorbent [38]. This decrease occurred at pH 9 for all masses of the adsorbent which may be due to the precipitation of the metal hydroxides in the basic solution [39]. The given results show also that at all pH values, the % of metal removal is increased with the increase of the copolymer mass. At pH 7, the metal removal percentages are 35.54%, 38.38%, 39.32% and 40.09% for the adsorbent masses of 0.05 g, 0.10 g, 0.15 g and 0.2 g respectively. It noticed also that there is slight increase in the metal ion uptake on increasing the copolymer mass from 0.15 g to 0.20 g. The increase of the removal of Cu(II) ions with increasing the mass of adsorbent which is directly proportional to the adsorption capacity by the grafted copolymer, may be due to the increase of the polymer sites available for chelation. The effect of the mass of adsorbent on the extent of metal removal was also investigated and the results reveal that removal of Cu (II) ions increases with increasing the mass of adsorbent. Results also show that the amount of metal ions removed by the graft copolymer, Cs-g-PVP, slightly increases with the increase of the mass of adsorbent from 0.15 g to 0.2 g. The increase of the metal removal, which is directly proportional to the adsorption capacity by the grafted copolymer, with increase of the mass of adsorbent may be due to the increase of the polymer sites available for chelation.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e3.4 Metal removal by Cs-g-PVP/f-MWCNTs hybrids\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eFurther investigations were performed for copper (II) removal using Cs-g-PVP/f-MWCNTs (containing 3wt% and/or 5wt% by weight) hybrids as metal adsorbent. Removal efficiency (R%) of metal removal by both Cs and Cs/f-MWCNTs are also given for comparison. Adsorbent mass fixed at 0.15 g at pH 7. The results are represented in Figure 5. The results show the % metal removal by the adsorbent, Cs-g-PVP/f-MWCNTs that containing 3wt% of the f-MWCNTs is 98.80 while the hybrid of 5wt% f-MWCNTs has metal removal % of 99.01. The ability of Cs and Cs/f-MWCNTs, containing 3wt% and 5wt% by weight, of f-MWCNTs was also investigated. The results indicated that the removal of Cu (II) ions from the aqueous solution reached 76.38, 84.36 and 89.19 for the three samples respectively. The observed high significant enhancement of metal removal % of these samples confirms the removal efficiency of f-MWCNTs which increases with increasing of its mass. This may be due to the presence of more negatively charged oxygen-containing groups on the oxidized or functionalized form of MWCNTs that have the affinity to attract the copper cations from the aqueous solutions [27].\u003c/p\u003e\n\u003cp\u003eThe incorporation of Cu(II) in Cs-g-PVP and Cs-g-PVP/f-MWCNTs 5wt% was confirmed by SEM analysis, Figure 6 (a,c). Figure 6 (a) showed the presence of copper metal ions on the Cs-g-PVP polymeric surface that appeared as bright spots. Figure 6 (c) shows the SEM image of the as-prepared Cs-g-PVP/f-MWCNTs 5wt% after Cu(II) ions adsorption process. In figure 6 (c) shows that f-MWCNTs appeared as sequestered within regions of chitosan-g-PVP that probably considered as the more hydrophobic phase on the polymeric hybrid. The EDX profile showed peaks for C, N, O and Cu as elemental constituents of the grafted copolymer, Cs-g-PVP and Cs-g-PVP/f-MWCNTs after adsorption of Cu(II) (Figure 6b,d). In EDX, the chemical compositions of Cs-g-PVP/Cu in weight% showed (C, N, O and Cu) was found (57.2 wt%, 5.4 wt%, 25.4 w% and 12.0 wt%) (Figure 6c). However, the chemical compositions of Cs-g-PVP/f-MWCNTs/Cu showed (C, N, O and Cu) was estimated to be (56.1 wt%, 5.2 wt%, 26.5 w% and 12.1 wt%) (Figure 6d). Also mapping of each element in Cs-g-PVP/f-MWCNTs/Cu sample was represented in figure 6e. Thus, these results are confirming that the as prepared Cs-g-PVP and Cs-g-PVP/f-MWCNTs was an efficient material for Cu-adsorption in aqueous solutions.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAntibacterial activity\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe antimicrobial activity of chitosan (Cs), chitosan grafted copolymer (Cs-g-PVP) and two grafted copolymers/f-MWCNTs hybrids (Cs-g-PVP/f-MWCNTs hybrids that containing 3wt% and 5wt% by weight of the MWCNTs) were evaluated\u0026nbsp;against the gram +ve bacteria (\u003cem\u003eB\u003c/em\u003e. \u003cem\u003eSubtitles\u003c/em\u003e, \u003cem\u003eSt\u003c/em\u003e. \u003cem\u003eaurous\u003c/em\u003e and \u003cem\u003eSt\u003c/em\u003e. \u003cem\u003efaecalis\u003c/em\u003e)\u0026nbsp;and the gram -ve bacterial strains (\u003cem\u003eE\u003c/em\u003e. \u003cem\u003ecoli\u003c/em\u003e, \u003cem\u003eN\u003c/em\u003e. \u003cem\u003egonorrhoeae\u003c/em\u003e\u003cem\u003e\u0026nbsp;\u003c/em\u003eand \u003cem\u003eP\u003c/em\u003e. \u003cem\u003eaeruginosa\u003c/em\u003e) that isolated from animal origin. Agar disk diffusion method was used for the determination of the preliminary antibacterial and Ampicillin was used as reference antibacterial drugs. All of the investigated samples showed, in vitro, antibacterial activity against the tested microorganisms. The results of antibacterial activity of the samples under investigation using inhibition zone method are listed in Tables 2.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eThe results showed that when compared to pristine chitosan, Cs-g-PVP had improved antibacterial activity against all strains of gram-positive and gram-negative bacteria. As a result, Cs has antibacterial efficacy against both types of bacterial strains in terms of inhibition zone diameter. The inhibition zone caused by Cs against the gram +ve bacteria (\u003cem\u003eB\u003c/em\u003e. \u003cem\u003eSubtitles\u003c/em\u003e, \u003cem\u003eSt\u003c/em\u003e. \u003cem\u003eaurous\u003c/em\u003e and \u003cem\u003eSt\u003c/em\u003e. \u003cem\u003efaecalis\u003c/em\u003e) are 13, 15 and 12 with efficiencies of 65, 83 and 67%, respectively with respect to the reference drug. On the other hand, the antibacterial activity of by the effect of Cs against the gram -ve bacterial strains (\u003cem\u003eE\u003c/em\u003e. \u003cem\u003ecoli\u003c/em\u003e, \u003cem\u003eN\u003c/em\u003e. \u003cem\u003egonorrhoeae\u003c/em\u003e and \u003cem\u003eP\u003c/em\u003e. \u003cem\u003eaeruginosa\u003c/em\u003e) are 14, 11 and 12 with efficiencies of 64, 55 and 71%, respectively when compared to the standard reference antibacterial drug. The insertion of 4-vinylpyridine (4-VP) as blocks via grafting copolymerization with Cs yielding Cs-g-PVP improved the antibacterial activity of this grafted copolymer against all tested microbes, according to the results of Table 2.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eIn comparison to the reference drug, the antibacterial efficiency for gram +ve bacteria (\u003cem\u003eB\u003c/em\u003e. \u003cem\u003eSubtitles\u003c/em\u003e, \u003cem\u003eSt\u003c/em\u003e. \u003cem\u003eaurous\u003c/em\u003e, and \u003cem\u003eSt\u003c/em\u003e. \u003cem\u003efaecalis\u003c/em\u003e) were 85, 94, and 83, respectively.\u0026nbsp;The antibacterial activity of Cs-g-PVP against the gram -ve bacterial strains (\u003cem\u003eE\u003c/em\u003e. \u003cem\u003ecoli\u003c/em\u003e, \u003cem\u003eN\u003c/em\u003e. \u003cem\u003egonorrhoeae\u003c/em\u003e and \u003cem\u003eP\u003c/em\u003e. \u003cem\u003eaeruginosa\u003c/em\u003e) reached 86, 85 and 94%, respectively with respect to the reference antibacterial drug. As a result, the Cs-g-PVP exhibit better efficiency against G -ve bacterial strains than the G +v kinds, according to the given results. These results could be explained by the electrostatic interaction between positively charged chitosan molecules and negatively charged microbial cell membranes, which is the first proposed accepted mechanism for chitosan antibacterial activity [40].\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eThe second predicted action mechanism is chitosan\u0026apos;s binding to microbe DNA, which results in mRNA and protein synthesis suppression in the nuclei of bacteria due to chitosan penetration. [41]. Based on the well-known biological properties of nitrogen containing six membered aromatic heterocyclic compounds and their derivatives [42], the observed increased antibacterial activity of Cs-g-PVP can be attributed to the PVP blocks in the grafted copolymeric chains. Additionally, the hydrophobic character of 4-VP in the copolymer chains increases the density of positive charges on the system, which may favor microbial cell attachment to the antibacterial system. As a result, 4-VP-based polymers or copolymers are intriguing materials with a variety of uses, including antibacterial materials [43-44]. Despite its well-known antibacterial properties, applications of Cs are limited due to undesirable properties such as low solubility and chemical stability [45-47]. As a result, various modifications or the addition of reinforcement materials may give rise to improvement to the physicochemical properties of chitosan, allowing it to be used in a wider range of applications.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eMultiwalled carbon nanotubes (MWCNTs) have thus been proposed as an excellent material to utilize as inorganic fillers for reinforcing or toughening polymeric materials [48], in addition to the grafting of 4-VP onto chitosan performance. Two samples of Cs-g-PVP containing 3 and 5% by weight of MWCNTs were functionalized as stated in the experimental section, affording two hybrids of Cs-g-PVP/f-MWCNTs for testing their biological activity. Table 2 shows the antibacterial activity of the two hybrids against the bacterial strains that were examined. When compared to either chitosan or the reference drug, the results showed that the two hybrids had much higher antibacterial efficacy against both types of bacteria, G +ve and G -ve bacteria. Antibacterial activity of the hybrid containing 3% by weight of f-MWCNTs against G +ve bacterial strains (\u003cem\u003eB\u003c/em\u003e. \u003cem\u003eSubtitles\u003c/em\u003e, \u003cem\u003eSt\u003c/em\u003e. \u003cem\u003eaureus\u003c/em\u003e, and \u003cem\u003eSt\u003c/em\u003e. \u003cem\u003efaecalis\u003c/em\u003e) was 95, 106, and 94 percent, respectively, as compared to the conventional drug.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eIn comparison to the reference drug, the obtained antibacterial activity of the same sample against G -ve bacteria (E. coli, N. gonorrhoeae, and P. aeruginosa) was 114, 110, and 106 respectively. The antibacterial activity effectiveness of the other hybrid, which contained 5wt% by weight of f-MWCNTs, was the highest of the investigated samples. In comparison to the reference antibacterial drug, the inhibitory effect of this hybrid revealed inhibition zones of 20, 21, and 17 mm, respectively, with efficiency of 100, 117, and 94 % against G +ve bacteria (\u003cem\u003eB\u003c/em\u003e. \u003cem\u003eSubtitles\u003c/em\u003e, \u003cem\u003eSt\u003c/em\u003e. \u003cem\u003eaurous\u003c/em\u003e, and \u003cem\u003eSt\u003c/em\u003e. \u003cem\u003efaecalis\u003c/em\u003e). When compared to the reference drug, the examined hybrid recorded inhibitory zones of 26, 24 and 21 mm for the G -ve bacterial strains (\u003cem\u003eE\u003c/em\u003e. \u003cem\u003ecoli\u003c/em\u003e, \u003cem\u003eN\u003c/em\u003e. \u003cem\u003egonorrhoeae\u003c/em\u003e, and \u003cem\u003eP\u003c/em\u003e. \u003cem\u003eaeruginosa\u003c/em\u003e), with efficiencies of 118, 120, and 124 %, respectively. The presence of f-MWCNTs in the tested samples is responsible for the observed high antibacterial activity of the two hybrids. MWCNTs have been shown to have strong inhibitory effects on a variety of bacteria in previous work [49].\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eAll postulated mechanisms to explain the bactericidal effect of CNTs in general are not fully known, and there are numerous factors that influence its antibacterial action. The diameter, electrical structure, residual catalyst, length, surface functional group, and other parameters are among them. [50]. In terms of the functionalized MWCNTs employed in this investigation, it has been noted that functionalization is a good way to improve their dispersion in different matrices while also increasing biocompatibility and lowering toxicity in human cells [51]. The optical density of E. coli was significantly reduced when amine or carboxyl moieties were added to MWCNT. According to certain observations, the functionalized carboxylated MWCNTs increased membrane roughness and hydrophilicity, which made them more resistant to bacterial adherence. These findings suggested that f-MWCNT surfaces could be used in the manufacture of medical devices and biomedical applications [52-53].\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eThe incorporation of MWCNTs or f-MWCNTs into chitosan or other synthetic polymers to obtain potentially helpful antibacterial surfaces against Gram-positive and Gram-negative bacteria has been investigated. This could lead to the development of unique physicochemical properties for these polymeric substrates, as well as the prospect of using these composites in a variety of biological applications such as tissue engineering, biosensing, wound dressing, and drug administration [54-55].\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003eFigure\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e7\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003eillustrates\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003ethe\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003eantibacterial efficiency of the investigated samples with respect to the standard reference drug.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eTable 2\u003c/strong\u003e: The antimicrobial activities of the investigated samples against some G +ve and G -ve bacterial strains\u0026nbsp;\u003c/p\u003e\n\u003ctable border=\"1\" cellpadding=\"0\" cellspacing=\"0\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd rowspan=\"3\" valign=\"top\" width=\"16.187594553706504%\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003eSample\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"10\" valign=\"top\" width=\"83.8124054462935%\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003eInhibition zone diameter (mm/mg sample)\u003c/p\u003e\u0026nbsp;\u0026nbsp;\u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"13.333333333333334%\"\u003e\n \u003cp\u003e\u003cem\u003e\u0026nbsp;\u003c/em\u003e\u003c/p\u003e\n \u003cp\u003e\u003cem\u003eBacillus Subtitles\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" valign=\"top\" width=\"19.0990990990991%\"\u003e\n \u003cp\u003e\u003cem\u003e\u0026nbsp;\u003c/em\u003e\u003c/p\u003e\n \u003cp\u003e\u003cem\u003eStaphylococcus aurous\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" valign=\"top\" width=\"17.47747747747748%\"\u003e\n \u003cp\u003e\u003cem\u003e\u0026nbsp;\u003c/em\u003e\u003c/p\u003e\n \u003cp\u003e\u003cem\u003eStreptococcus faecalis\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 14%;\" valign=\"top\" width=\"15.315315315315315%\"\u003e\n \u003cp\u003e\u003cem\u003e\u0026nbsp;\u003c/em\u003e\u003c/p\u003e\n \u003cp\u003e\u003cem\u003eEscherichia coli\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"3\" style=\"width: 15.75%;\" valign=\"top\" width=\"17.2972972972973%\"\u003e\n \u003cp\u003e\u003cem\u003e\u0026nbsp;\u003c/em\u003e\u003c/p\u003e\n \u003cp\u003e\u003cem\u003eNeisseria gonorrhea\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"17.47747747747748%\"\u003e\n \u003cp\u003e\u003cem\u003e\u0026nbsp;\u003c/em\u003e\u003c/p\u003e\n \u003cp\u003e\u003cem\u003ePseudomonas gonorrhoeae\u0026nbsp;\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"14.954954954954955%\"\u003e\u0026nbsp;\u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" valign=\"top\" width=\"18.01801801801802%\"\u003e\n \u003cp\u003eG+ve\u003c/p\u003e\u0026nbsp;\u0026nbsp;\u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" valign=\"top\" width=\"16.756756756756758%\"\u003e\u0026nbsp;\u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 14%;\" valign=\"top\" width=\"16.396396396396398%\"\u003e\u0026nbsp;\u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"3\" style=\"width: 11.75%;\" valign=\"top\" width=\"15.855855855855856%\"\u003e\n \u003cp\u003eG-ve\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"18.01801801801802%\"\u003e\u0026nbsp;\u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"16.163141993957705%\"\u003e\n \u003cp\u003eDMSO\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"11.178247734138973%\"\u003e\n \u003cp\u003e0.0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" valign=\"top\" width=\"16.012084592145015%\"\u003e\n \u003cp\u003e0.0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" valign=\"top\" width=\"14.652567975830816%\"\u003e\n \u003cp\u003e0.0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 14%;\" valign=\"top\" width=\"12.83987915407855%\"\u003e\n \u003cp\u003e0.0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"3\" style=\"width: 15.75%;\" valign=\"top\" width=\"14.501510574018127%\"\u003e\n \u003cp\u003e0.0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"14.652567975830816%\"\u003e\n \u003cp\u003e0.0\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"16.163141993957705%\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003eAmpicillin (100\u0026micro;g/mL)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"11.178247734138973%\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e20\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" valign=\"top\" width=\"16.012084592145015%\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e18\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" valign=\"top\" width=\"14.652567975830816%\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e18\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 14%;\" valign=\"top\" width=\"12.83987915407855%\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e22\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"3\" style=\"width: 15.75%;\" valign=\"top\" width=\"14.501510574018127%\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e20\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"14.652567975830816%\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e17\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"16.163141993957705%\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003eCs\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"11.178247734138973%\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e13\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" valign=\"top\" width=\"16.012084592145015%\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e15\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" valign=\"top\" width=\"14.652567975830816%\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e12\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 14%;\" valign=\"top\" width=\"12.83987915407855%\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e14\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"3\" style=\"width: 15.75%;\" valign=\"top\" width=\"14.501510574018127%\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e11\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"14.652567975830816%\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e12\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"16.163141993957705%\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003eCs-g-PVP\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003eCs-g-PVP/MWCNTs (3%)\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003eCs-g-PVP/MWCNTs (5%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"11.178247734138973%\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e17\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e19\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e20\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" valign=\"top\" width=\"16.012084592145015%\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e17\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e19\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e21\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" valign=\"top\" width=\"14.652567975830816%\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e15\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e17\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e17\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 14%;\" valign=\"top\" width=\"12.83987915407855%\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e19\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e25\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e26\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"3\" style=\"width: 15.75%;\" valign=\"top\" width=\"14.501510574018127%\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e17\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e22\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e24\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"14.652567975830816%\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e16\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e18\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e21\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e"},{"header":"Conclusions","content":"\u003cp\u003eIn this study, it was investigated that the catalytic performance of Cs-g-PVP and Cs-g-PVP/f-MWCNTs hybrids was explored in the batch adsorption of Cu(II) in aqueous solutions as simulated wastewater. The results revealed that upon conjugation of f-MWCNTs with Cs-g-PVP, a covalent integration between f-MWCNTs and Cs-g-PVP have been accomplished. The addition of f-MWCNTs to Cs-g-PVP copolymer enhanced the thermal and chemical stability of the polymeric materials because f-MWCNTs possess high tensile strengths, and are ultra-light weight. The study was extended for testing the bioactivity of the as-prepared samples. It was revealed that Cs-g-PVP/f-MWCNTs, having 5% by weight of the f-MWCNTs, exhibited the highest antibacterial activity. The presented polymeric hybrids can be used in wastewater treatment applications for Cu(II) removal and inhibition the growth of bacteria in aqueous solution.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e \u003cstrong\u003eConflicts of interest\u003c/strong\u003e \u003cp\u003eThe authors have declared no conflict of interest.\u003c/p\u003e \u003c/p\u003e\u003ch2\u003eAcknowledgments\u003c/h2\u003e \u003cp\u003eThe authors acknowledge STDF (Egypt) for their valuable support through research project fund (project ID 27777).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eDATA AVAILABILITY STATEMENT\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e- All data generated or analysed during this study are included in this published article [and its supplementary information files]\u003c/strong\u003e\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eAhlafi H, Moussout H, Boukhlifi F, Echetna M, Bennani MN, Sliman SM. Kinetics of N-Deacetylation of Chitin Extracted from Shrimp Shells Collected from Coastal Area of Morocco. \u003cem\u003eMedit J of Chem\u003c/em\u003e. 2013; 2, 503-513.\u003c/li\u003e\n\u003cli\u003eVarma AJ, Deshpande SV, Kennedy JF. Metal complexation by chitosan and its derivatives: a review. \u003cem\u003eCarbohydr Polym\u003c/em\u003e. 2004; 55, 77\u0026ndash;93.\u003c/li\u003e\n\u003cli\u003eRavi Kumar MNV, Muzzarelli RAA, Muzzarelli C, Sashiwa H, Domb AJ. \u003cem\u003eChem Rev\u003c/em\u003e. 2004; 104, 6017\u0026ndash;6084. \u003c/li\u003e\n\u003cli\u003eKeyur D, Kevin K, Li J, Davidson PM, Zivanovic S, Meyer H. Nanofibrous chitosan non-woven for filtration applications. \u003cem\u003ePolymer\u003c/em\u003e. 2009; 50, 3661\u0026ndash;3669. \u003c/li\u003e\n\u003cli\u003eLin WJ, Chen TD, Liu CW. Synthesis and characterization of lactobionic acid grafted pegylated chitosan and nanoparticle complex application. \u003cem\u003ePolymer\u003c/em\u003e. 2009; 50, 4166\u0026ndash;4174.\u003c/li\u003e\n\u003cli\u003eMori T, Murakami M, Okumura M, Kadosawa T, Uede T, Fujinaga T. Mechanism of macrophage activation by chitin derivatives. J of Vet Med Sci 2005; 67, 51\u0026ndash;56.\u003c/li\u003e\n\u003cli\u003eWan NWS, Endud CS, Mayaner R. Removal of copper(II) ions from aqueous solution onto chitosan and cross-linked chitosan beads. React. \u003cem\u003eFunct Polym\u003c/em\u003e. 2002; 50, 181\u0026ndash;190.\u003c/li\u003e\n\u003cli\u003eBecker T, Schlaak M, Strasdeit H. Adsorption of nickel(II), zinc(II) and cadmium by new chitosan derivatives. \u003cem\u003eReact Funct Polym\u003c/em\u003e. 2000; 44, 289\u0026ndash;298.\u003c/li\u003e\n\u003cli\u003eSahin M, Kocak N, Arslan G, Ucan HI. Synthesis of Crosslinked Chitosan with Epichlorohydrin Possessing Two Novel Polymeric Ligands and Its Use in Metal Removal. \u003cem\u003eJ Inorg Organomet Polym\u003c/em\u003e. 2011; 21, 69\u0026ndash;80.\u003c/li\u003e\n\u003cli\u003eYang ZK, Yuan Y. Studies on the synthesis and properties of hydroxyl aza crown ether-grafted chitosan. \u003cem\u003eJ Appl Polym Sci\u003c/em\u003e. 2001; 82, 1838\u0026ndash;1843. \u003c/li\u003e\n\u003cli\u003eChen S, Wang Y. Study on b-cyclodextrin grafting with chitosan and slow release of its inclusion complex with radioactive iodine. \u003cem\u003eJ Appl Polym Sci\u003c/em\u003e. 2001; 82, 2414\u0026ndash;2421. \u003c/li\u003e\n\u003cli\u003eJung BO, Kim CH, Choi KS, Lee YM, Kim JJ. Preparation of amphiphilic chitosan and their antimicrobial activities. \u003cem\u003eJ Appl Polym Sci\u003c/em\u003e. 1999; 72, 1713\u0026ndash;1719.\u003c/li\u003e\n\u003cli\u003eZohuriaan-mehr MJ. Advances in chitin and chitosan modification through graft copolymerization: A comprehensive review. \u003cem\u003eIran Polym J\u003c/em\u003e. 2005; 14, 235-265.\u003c/li\u003e\n\u003cli\u003eSabaa MW, Elzanaty AM, Abdel-Gawad OF, Arafa EG. Synthesis, characterization and antimicrobial activity of Schiff bases modified chitosan-graft poly(acrylonitrile). Int \u003cem\u003eJ of\u003c/em\u003e \u003cem\u003eBiol\u003c/em\u003e \u003cem\u003eMacromol\u003c/em\u003e. 2018; 109, 1280\u0026ndash;1291.\u003c/li\u003e\n\u003cli\u003eYanovska E, Ryabchenko K, Ianovska M, Kichkiruk O, Tertykh V, Davydov V. Adsorption of tungsten, molybdenum, vanadium and chromium from aqueous solutions using pine sawdust-polyaniline composites. \u003cem\u003eNord Pulp Pap Res J\u003c/em\u003e. 2014; 29, 425-433.\u003c/li\u003e\n\u003cli\u003eYanovska ES, Dadashev AD, Tertykh VA (2009) Inorganic anion\u0026ndash;exchanger based on silica with grafted polyhexamethyleneguanidine hydrochloride. \u003cem\u003eFunct Mat\u003c/em\u003e 16:105-112. \u003c/li\u003e\n\u003cli\u003eDadashev AD, Tertykh VA, Yanovska ES, Yanova KV. New approach to synthesis of silica with chemically bound guanidine hydrochloride for preconcentration of metal ions. \u003cem\u003eAm J\u003c/em\u003e \u003cem\u003eAnal Chem\u003c/em\u003e. 2016; 7, 411-420.\u003c/li\u003e\n\u003cli\u003eChen Y, Zhao, W, Zhang J. Preparation of 4-vinylpyridine (4VP) resin and its adsorption performance for heavy metal ions. \u003cem\u003eRSC Adv\u003c/em\u003e. 2017; 7, 4226\u0026ndash;4236.\u003c/li\u003e\n\u003cli\u003eShaglaeva NS, Baginov DB, Filatova EG, Pozhidaev YuN, Podgorbunskaya TA, Stanevich LM. Adsorbent of Noble Metals, Based on Copolymers of Divinyl Sulfi de and 4-Vinylpyridine. Russ J of Appl Chem. 2019; 92, 92\u0026minus;97.\u003c/li\u003e\n\u003cli\u003eLagan\u0026agrave; P, Visalli G, Facciol\u0026agrave; A, Ciarello MP, Lagan\u0026agrave; A, Iannazzo D, Pietro AD. Is the Antibacterial Activity of Multi-Walled Carbon Nanotubes (MWCNTs) Related to Antibiotic Resistance? An Assessment in Clinical Isolates. \u003cem\u003eInt J Environ Res, Public Health\u003c/em\u003e. 2021; 18, 9310\u003c/li\u003e\n\u003cli\u003eTjong SC, Structural and mechanical properties of polymer nanocomposites. \u003cem\u003eMat Sci and\u003c/em\u003e \u003cem\u003eEng: R: Reports\u003c/em\u003e. 2006; 53, 73\u0026ndash;197.\u003c/li\u003e\n\u003cli\u003eMasheane M, Nthunya L, Soraya Malinga S, Nxumalo E, Tobias Barnard T, Sabelo M. Antimicrobial Properties of Chitosan-Alumina/f-MWCNT Nanocomposites. \u003cem\u003eJ of Nanotechnol\u003c/em\u003e 2016; Article ID 5404529, 8 pages.\u003c/li\u003e\n\u003cli\u003eKosa SA, Al-Zhrani G, Abdel Salam M. Removal of heavy metals from aqueous solutions by multi-walled carbon nanotubes modified with 8-hydroxyquinoline. \u003cem\u003eChem Eng J\u003c/em\u003e. 2012; 181\u0026ndash;182, 159\u0026ndash;168.\u003c/li\u003e\n\u003cli\u003eK.V. Harish Prashanth, R.N. Tharanathan, Studies on graft copolymerization of chitosan with synthetic monomers. \u003cem\u003eCarbohydr. Polym\u003c/em\u003e. 2003; 54, 343\u0026ndash;351.\u003c/li\u003e\n\u003cli\u003eMohamed RR, Sabaa MW. Chemically Induced Graft Copolymerization of Acrylonitrile onto Carboxymethyl Chitosan and its Modification to Amidoxime Derivative. \u003cem\u003eJ Appl Polym Sci\u003c/em\u003e. 2010; 116, 413\u0026ndash;421.\u003c/li\u003e\n\u003cli\u003eSantangelo S, Messina G, Faggio G, Abdul Rahim SH, Milone C. Effect of sulphuric\u0026ndash;nitric acid mixture composition on surface chemistry and structural evolution of liquid-phase oxidized carbon nanotubes. \u003cem\u003eJ Raman Spectr\u003c/em\u003e. 2012; 43, 1432-1442. \u003c/li\u003e\n\u003cli\u003e27. Rodr\u0026iacute;guez C, Leiva E. Enhanced Heavy Metal Removal from Acid Mine Drainage Wastewater Using Double-Oxidized Multiwalled Carbon Nanotubes. \u003cem\u003eMolecules\u003c/em\u003e 2019, 25, 111\u003c/li\u003e\n\u003cli\u003eJeong JH, Shin KS, Lee JW, Park EJ, Son SY. Analysis of a novel class 1 integron containing metallo-beta-lactamase gene VIM-2 in Pseudomonas aeruginosa. \u003cem\u003eJ Microbiol\u003c/em\u003e. 2009; 47, 753\u0026ndash;759.\u003c/li\u003e\n\u003cli\u003eKanokwiroon K, Teanpaisan R, Wititsuwannakul D, Hooper AB, Wititsuwannakul R. \u003cem\u003eMycoses\u003c/em\u003e. 2008; 51, 301\u0026ndash;307. \u003c/li\u003e\n\u003cli\u003eNational Committee for Clinical Laboratory Standards, Reference method for Broth Dilution Antifungal susceptibility testing of Conidium-Forming Filamentous Fungi: proposed guideline M38-A. NCCLS, Wayne, PA, USA. 2002.\u003c/li\u003e\n\u003cli\u003e31. National Committee for Clinical Laboratory Standards, Method for antifungal disk diffusion susceptibility testing of yeast: proposed guideline M44-P. NCCLS, Wayne, PA, USA.2003. \u003c/li\u003e\n\u003cli\u003eLiebowitz LD, Ashbee HR, Evans EGV, Chong Y, Mallatova N, Zaidi M, Gibbs D. A two-year global evaluation of the susceptibility of Candida species to fluconazole by disk diffusion. \u003cem\u003eDiagn. Microbiol. Infect. Dis\u003c/em\u003e. 2001; 40, 27\u0026ndash;33. \u003c/li\u003e\n\u003cli\u003eMatar ML, Ostrosky-Zeichner L, Paetznick VL, Rodriguez JR, Chen E, Rex JH. Correlation between E-Test, Disk Diffusion, and Microdilution Methods for Antifungal Susceptibility Testing of Fluconazole and Voriconazole. \u003cem\u003eAntimicrob\u003c/em\u003e \u003cem\u003eAgents Chemother\u003c/em\u003e. 2003; 47, 1647\u0026ndash;1651.\u003c/li\u003e\n\u003cli\u003eElkholy SS, Khalil KhD, Elsabee MZ. Homogeneous and heterogeneous grafting of 4-vinylpyridine onto chitosan. \u003cem\u003eJ Appl Polym Sci\u003c/em\u003e. 2006; 99, 3308\u0026ndash;3317\u003c/li\u003e\n\u003cli\u003eZiegler-Borowska M, Chełminiak D, Kaczmarek H. Thermal stability of magnetic nanoparticles coated by blends of modified chitosan and poly(quaternary ammonium) salt. \u003cem\u003eJ Therm Anal Calorim\u003c/em\u003e. 2015; 119, 499\u0026ndash;506.\u003c/li\u003e\n\u003cli\u003eZeng L, Qin C, Wang L, Li W. Volatile compounds formed from the pyrolysis of chitosan. \u003cem\u003eCarbohydr Polym\u003c/em\u003e. 2011; 83, 1553\u0026ndash;1557.\u003c/li\u003e\n\u003cli\u003eZalloum HM, AL-Qodah Z, MUBARAK MS. Copper Adsorption on Chitosan-Derived Schiff Bases. \u003cem\u003eJ of Macromol Sci R, Part A: Pure and Appl Chem\u003c/em\u003e. 2009; 46, 46\u0026ndash;57.\u003c/li\u003e\n\u003cli\u003eShafa-Amry NN, Khalili FI, Ebraheem KAK, Mubarak MS. Synthesis and chelation properties of Mannich polymers derived from piperazine and some hydroxy benzaldoximes. \u003cem\u003eReact Funct Polym\u003c/em\u003e. 2006; 66, 789-794.\u003c/li\u003e\n\u003cli\u003eBhatt RR, Shah BA, Shah AV. Uptake of heavy metal ions by chelating ion-exchange resin derived from p-hydroxibenzoic acid form aldehyde resorcinol: synthesis, characterization and sorption dynamics. \u003cem\u003eThe Malays J of Anal Sci\u003c/em\u003e. 2012; 16, 117-133.\u003c/li\u003e\n\u003cli\u003eFeng QL, Wu J, Chem GQ, Cui FZ, Kem TN. A Mechanistic Study of the Antibacterial Effect of Silver Ions on Escherichia coli and Staphylococcus aureus. \u003cem\u003eJ Biomed Mater Res\u003c/em\u003e. 2000; 52, 662\u0026ndash;668. \u003c/li\u003e\n\u003cli\u003eHadwiger LA, Kendra DF, Fristensky BW, Wagoner W. Chitosan both activates genes in plants and inhibits RNA synthesis in fungi, in: R.A.A. Muzzarelli, C. Jeuniaux, C.W. Gooday (Eds.), in \u003cem\u003eChitin in Nature and Technol\u003c/em\u003e, Plenum Press, New York. 1986; 209\u0026ndash;221.\u003c/li\u003e\n\u003cli\u003eAltaf AA, Shahzad A, Gul Z, Rasool N, Badshah A, Lal B, Khan E. A review on the medicinal importance of pyridine derivatives. \u003cem\u003eJ of Drug Design and Med Chem\u003c/em\u003e. 2015; 29, 1-11.\u003c/li\u003e\n\u003cli\u003eLi Y, Yang MJ, She Y. Humidity sensitive properties of crosslinked and quaternized poly(4-vinylpyridine co-butyl methacrylate). \u003cem\u003eSens and Actuat B\u003c/em\u003e. 2005; 107, 252-257.\u003c/li\u003e\n\u003cli\u003eLi D, He Q, Cui Y, Li J. Fabrication of pH-responsive nanocomposites of gold nanoparticles/poly(4- vinylpyridine). \u003cem\u003eJ Chem Mater\u003c/em\u003e. 2007; 19, 412-417.\u003c/li\u003e\n\u003cli\u003eChen S, Wu G, Long D, Liu Y. Preparation, characterization and antibacterial activity of chitosan-Ca3V10O28 complex membrane. \u003cem\u003eCarbohydr\u003c/em\u003e \u003cem\u003ePolym\u003c/em\u003e. 2006; 64, 92\u0026ndash;97.\u003c/li\u003e\n\u003cli\u003eYadav SK, Mahapatra SS, Yadav MK, Dutta PK. Mechanically robust biocomposite films of chitosan grafted carbon nanotubes via the [2 + 1] cycloaddition of nitrenes. \u003cem\u003eRSC Advances\u003c/em\u003e. 2013; 3, 23631\u0026ndash;23637. \u003c/li\u003e\n\u003cli\u003eMi FL, Wu SJ, Lin FM. Adsorption of copper(II) ions by a chitosan-oxalate complex biosorbent. \u003cem\u003eInt J of Biol Macromol\u003c/em\u003e. 2015; 72, 136\u0026ndash;144.\u003c/li\u003e\n\u003cli\u003eTjong SC. Structural and mechanical properties of polymer nanocomposites. \u003cem\u003eMaterials\u003c/em\u003e \u003cem\u003eScience and Engineering: R.\u003c/em\u003e \u003cem\u003eReports\u003c/em\u003e. 2006; 53, 73\u0026ndash;197.\u003c/li\u003e\n\u003cli\u003eChen H, Wang B, Gao D, Guan M, Zheng L, Ouyang H, Chai Z, Zhao Y, Feng W. Broad-spectrum antibacterial activity of carbon nanotubes to human gut bacteria. \u003cem\u003eSmall\u003c/em\u003e. 2013; 9, 2735\u0026ndash;2746.\u003c/li\u003e\n\u003cli\u003eKang S, Herzberg M, Rodrigues DF, Elimelech M. Antibacterial effects of carbon nanotubes: size does matter! \u003cem\u003eLangmuir.\u003c/em\u003e 2008; 24, 6409\u0026ndash;6413.\u003c/li\u003e\n\u003cli\u003eUpadhyayula VKK, Gadhamshetty V. Appreciating the role of carbon nanotube composites in preventing biofouling and promoting biofilms on material surfaces in environmental engineering: a review. \u003cem\u003eBiotechnol Adv\u003c/em\u003e. 2010; 28, 802\u0026ndash;816.\u003c/li\u003e\n\u003cli\u003eKumar S, Bose S, Chatterjee K. Amine-functionalized multiwall carbon nanotubes impart osteo inductive and bactericidal properties in poly(\u0026epsilon;-caprolactone) composites. \u003cem\u003eRSC Adv\u003c/em\u003e. 2014; 4, 19086\u0026ndash;19098.\u003c/li\u003e\n\u003cli\u003eAlizadeh A, Razmjou A, Ghaedi M, Jannesar R. Nanoporous solid-state membranes modified with multi-wall carbon nanotubes with anti-biofouling property. \u003cem\u003eInt J Nanomedicine\u003c/em\u003e. 2019; 14, 1669\u0026ndash;1685.\u003c/li\u003e\n\u003cli\u003eNie C, Cheng C, Peng Z, Ma L, He C, Xia Y, Zhao C. (2016). Mussel-inspired coatings on Ag nanoparticle-conjugated carbon nanotubes: bactericidal activity and mammal cell toxicity. \u003cem\u003eJ Mater Chem. \u003c/em\u003e2016;\u003cem\u003e \u003c/em\u003eB 4, 2749\u0026ndash;2756.\u003c/li\u003e\n\u003cli\u003eEl-Ghany NAA. Antimicrobial activity of new carboxymethyl chitosan\u0026ndash;carbon nanotube biocomposites and their swellability in different pH media. \u003cem\u003eJ. Carbohyd. \u003c/em\u003e2017; 36, 31-44.\u003cem\u003e \u003c/em\u003e\u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"scientific-reports","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"scirep","sideBox":"Learn more about [Scientific Reports](http://www.nature.com/srep/)","snPcode":"","submissionUrl":"","title":"Scientific Reports","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Scientific Reports","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"Chitosan-grafted-4-vinylpyridine, Carbon nanotubes, C(II) ions removal, Antibacterial activity","lastPublishedDoi":"10.21203/rs.3.rs-1640092/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-1640092/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eChitosan-grafted-4-vinylpyridine (Cs-g-PVP) was prepared utilizing free radical copolymerization method. The chemical structure of the produced Cs-g-PVP was confirmed by FTIR spectroscopy, in addition thermal gravimetric analysis (TGA) was used to assess its thermal stability, and scanning electron microscopy (SEM) was used to examine its morphology. Enhancement of the chemical and physical proprieties was achieved by adding functionalized multi-walled carbon nanotubes (f-MWCNTs) to produce two polymeric hybrids of Cs-g-PVP/f-MWCNTs (I and II) with 3wt% and 5wt% f-MWCNTs, respectively. Characterization of these hybrids was performed using TGA, SEM and EDX analysis. Using a batch adsorption approach, the produced grafted copolymer (Cs-g-PVP) and the hybrids (Cs-g-PVP/f-MWCNTs I and II) were tested for adsorption of Cu(II) ions in aqueous solution using initial concentration of CuCl\u003csub\u003e2\u003c/sub\u003e equals to 5x10\u003csup\u003e\u0026minus;\u0026thinsp;3\u003c/sup\u003e mol/L at different pH values (i.e. 4, 7, and 9). Antibacterial activity of the Cs-g-PVP and the hybrids was evaluated against three Gram\u0026thinsp;+\u0026thinsp;ve bacteria (\u003cem\u003eStaphylococcus aurous\u003c/em\u003e, \u003cem\u003eBacillus Subtitles\u003c/em\u003e and \u003cem\u003eStreptococcus faecalis\u003c/em\u003e) and three Gram \u0026ndash;ve bacteria (\u003cem\u003eEscherichia coli\u003c/em\u003e, \u003cem\u003ePseudomonas aeruginosa\u003c/em\u003e and \u003cem\u003eNeisseria gonorrhoeae\u003c/em\u003e. The results showed that the efficiency of the Cs-g-PVP copolymer showed significant increase after inclusion of the f-MWCNTs substrate towards Cu(II) removal and antibacterial agent.\u003c/p\u003e","manuscriptTitle":"Facile Synthesis of chitosan-g-PVP/f-MWCNTs for application in Cu(II) ions removal and for bacterial growth inhibition in aqueous solutions","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2022-06-07 19:04:58","doi":"10.21203/rs.3.rs-1640092/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Major revision","date":"2022-07-12T04:34:23+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2022-07-06T01:05:17+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"0d9d5028-8685-4929-bc2a-6626af163d79","date":"2022-07-01T14:21:16+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"efabd66b-cfb8-4fd3-882c-d6c2d7884757","date":"2022-06-20T17:37:36+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2022-06-17T20:04:24+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2022-05-31T17:38:34+00:00","index":"","fulltext":""},{"type":"editorInvited","content":"","date":"2022-05-31T12:19:28+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2022-05-31T12:16:28+00:00","index":"","fulltext":""},{"type":"submitted","content":"Scientific Reports","date":"2022-05-10T02:58:45+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"scientific-reports","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"scirep","sideBox":"Learn more about [Scientific Reports](http://www.nature.com/srep/)","snPcode":"","submissionUrl":"","title":"Scientific Reports","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Scientific Reports","inReviewEnabled":true,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"d5a51171-7a47-47f0-ad79-29cb84720d0c","owner":[],"postedDate":"June 7th, 2022","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"under-review","subjectAreas":[],"tags":[],"updatedAt":"2022-10-13T04:14:13+00:00","versionOfRecord":[],"versionCreatedAt":"2022-06-07 19:04:58","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-1640092","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-1640092","identity":"rs-1640092","version":["v1"]},"buildId":"cBFmMYwuxLRRLfASyISRj","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}