Fabrication and Characterization of Nano-loaded Recycled Materials for Water Purification, Part I: Iron Oxide Nanoparticles Incorporation

Fabrication and Characterization of Nano-loaded Recycled Materials for Water Purification, Part I: Iron Oxide Nanoparticles Incorporation | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Fabrication and Characterization of Nano-loaded Recycled Materials for Water Purification, Part I: Iron Oxide Nanoparticles Incorporation Amira Hassan, Ahmed Abd El-Aziz, Moahmed ELwi, Anke Klingner This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-6745323/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 05 Aug, 2025 Read the published version in Discover Materials → Version 1 posted 10 You are reading this latest preprint version Abstract This study investigates the development and performance of polyethylene terephthalate (PET) nanofiber, made from recycled PET bottles, for water purification applications. The research focuses on incorporating Iron Oxide (Fe 3 O 4 ) nanoparticles into this membrane, optimizing their performance for heavy metal ion removal. By refining the electrospinning process, the study successfully produced uniform nanofibers with enhanced filtration capabilities. A significant difference in the fibers' properties was observed by varying polymer concentrations in electrospinning solution. Nanofibers produced at a 10 wt.% concentration exhibited the highest tensile strength of 66 MPa and balanced flexibility, making them suitable for high-pressure filtration scenarios. The fibers at 15 wt.% demonstrated remarkable ductility with an elongation at break of 162%, ideal for dynamic filtration systems. The introduction of Iron Oxide (Fe 3 O 4 ) nanoparticles significantly increased the Ultimate Tensile Strength to 86 MPa. Adsorption tests revealed that the 10 wt.% fibers had the highest capacity for copper ion removal at 12 mg/g, attributed to their smaller fiber diameter and larger surface area. The addition of Fe 3 O 4 nanoparticles further improved the adsorption capacity, reaching 19.8 mg/g for heavy metal ions. This enhancement is attributed to the high surface energy and strong affinity of Fe 3 O 4 for contaminants. These findings underscore the potential of PET nanocomposites in providing efficient and sustainable water purification solutions, with performance tailored by adjusting polymer concentrations and nanoparticles integrations. Nanocomposites Nanoparticles Magnetic Nanoparticles Iron Oxide Electrospinning Recycled Materials Metal Ions Removal Wastewater Treatment Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 1 Introduction While over 70% of Earth's surface is covered by water, only 0.5% is fresh water. Egypt is particularly vulnerable to water scarcity, a situation worsened by rapid population growth and industrialization, leading to increased freshwater demand. This could result in a significant water deficit in Africa, estimated at 28–47% by 2030 [ 1 ]. Furthermore, water scarcity affects societal living standards and development opportunities [ 1 ]. The challenge of securing clean water is a critical global issue [ 1 ], [ 2 ]. The inadequacy of water treatment capacities in many regions [ 1 ] underscores the need for advanced water treatment techniques.[ 1 ]. Adding to the water scarcity crisis is the devastating impact of water pollution on both human health and the environment. It leads to the death of approximately 14,000 people daily [ 3 ], primarily due to untreated sewage contaminating drinking water in developing countries. This pollution affects aquatic ecosystems, reducing biodiversity and harming fish populations, which are crucial for human consumption[ 3 ]. While traditional methods like oxidation, electrocoagulation, and chlorination are used [ 4 ], they are often inefficient and environmentally harmful. Membrane technology, on the other hand, offers several advantages in water treatment, including no secondary contaminants, high selectivity, efficiency, and stability [ 4 ]. Techniques like microfiltration, ultrafiltration, nanofiltration, and reverse osmosis are part of this technology, proving effective in water separation and purification [ 4 ]. The performance of these membrane technologies is greatly influenced by the choice of materials and their preparation methods[ 4 ]. The urgent need for efficient water treatment is further compounded by the widespread presence of pollutants. Water pollution, primarily caused by organic or inorganic solutes and heavy metals like Hg, Cu, As, Cr, Zn, Pb, and Cd, is a significant global issue exacerbated by human activities and industrial processes. This pollution alters water's characteristics and quality, necessitating efficient treatment before community use. The increasing need for better water management and sustainable practices has led to a demand for advanced technologies. Nanoscience and nanotechnology are recognized for their potential to enhance environmentally friendly technologies for controlling water pollution[ 1 ], [ 5 ]. Nanofiber membranes, due to their large surface area, high porosity, ease of modification, and compatibility with other materials, show great potential in addressing water pollution issues [ 4 ], [ 6 ]. Electrospinning, a method for producing nanofibers from polymers, has gained attention for its simplicity and effectiveness [ 4 ], [ 7 ]. These electrospun nanofiber membranes exhibit enhanced performance in water treatment, overcoming limitations of traditional membranes such as low permeation flux and poor antifouling properties [ 4 ], [ 8 ]. Consequently, research focusing on electrospinning technology to develop nanofiber membranes with high flux, superior antifouling, mechanical qualities, and microporous penetrability for water treatment is increasingly popular [ 4 ], [ 9 ]. The effectiveness of nanoparticles in water filtration is significantly enhanced by their unique properties. Metallic nanoparticles, such as noble metals and iron, have notable characteristics like surface Plasmon resonance, magnetic and optical polarizability, and thermal conductivity. These properties lead to diverse applications in various industries, including water treatment [ 1 ]. Fe 3 O 4 nanoparticles are widely used as an adsorbent for water purification from contaminants. The synthesis of Fe 3 O 4 nanoparticles has been developed with various methods such as coprecipitation, solgel, hydrothermal, electrochemical, and microemulsion[ 10 ]. The coprecipitation method is the most commonly method since it is easy and efficient for the synthesis of Fe 3 O 4 nanoparticles[ 10 ]. Several studies used Fe 3 O 4 nanoparticles for metals adsorption such as arsenic[ 10 ], lead and chromium[ 10 ]. This focus on advanced materials and technologies extends to addressing the environmental challenges posed by plastic waste, particularly PET bottles. Global consumption of PET bottles has surged to 481.6 billion annually, raising significant concerns about their environmental impact [ 11 ]. Recycling PET bottles has become critical for environmental sustainability, as their non-biodegradable components contribute to ecosystem degradation. In this context, the use of electrospinning to create nanofibrous membranes from recycled PET bottles have emerged as a promising approach to mitigate environmental burdens and transform waste into valuable resources [ 11 ]. The abundance and affordability of PET scrap materials, coupled with the challenges of recycling, have further driven this innovative recycling effort [ 11 ]. This study aims to enhance global health and environmental protection by developing efficient, sustainable water purification technologies. Through the integration of Fe 3 O 4 nanoparticles within recycled electrospun PET nanofibers at varying polymer concentrations to innovate electrospun nanocomposites that function as water purifier. Concluded with various characterization techniques, the efficiency of these filters is thoroughly evaluated. Figure 1 . illustrates the main stages of the study. 2 Materials and Methods The PET nanofibers were synthesized utilizing recycled PET materials derived from Nestle water bottles. For the dissolution process of PET flakes, Trifluoroacetic acid (TFA) with a 99% purity level, acquired from Advent, India, and Dichloromethane (DCM) sourced from Power Chemical Egypt, Cairo. Iron (II) sulfate heptahydrate (FeSO 4 ·7H 2 O) and Iron (III) chloride tetrahydrate (FeCl 2 ·4H 2 O) from Sigma-Aldrich were used for Fe 3 O 4 nanoparticle synthesis. Ammonia hydroxide (25%) from Power Chemical Egypt, Cairo, was added to adjust pH. 2.1 Polymeric Nanofibers (Recycled PET Bottles): The process begins by collecting Nestle water bottles, which are manually cut into flakes. These flakes are cleaned with ethanol to remove contaminants and then dried to eliminate moisture. This preparation ensures the PET material is ready for electrospinning. The PET flakes are dissolved in a solvent mixture of trifluoroacetic acid (TFA) and dichloromethane (DCM) in a 1:4 ratio to create polymer solutions at three different concentrations: 10 wt.%, 15 wt.%, and 20 wt.%. The solution is allowed to sit for 24 hours at room temperature to ensure complete dissolution. A magnetic stirrer is then used for one hour to ensure uniformity, which is crucial for producing consistent nanofibers. 2.2 Preparation of Fe 3 O 4 Nanoparticles: Four grams Iron(II) sulfate heptahydrate (FeSO 4 ·7H 2 O) and 8 grams Iron(III) chloride tetrahydrate (FeCl 2 ·4H 2 O) are dissolved in 400 ml of deionized water to form the starting solution for magnetite nanoparticles. The solution is subsequently heated to 60°C and stirred for half an hour, allowing the salts to fully dissolve in preparation for nanoparticle formation. The growth phase begins with the addition of 25 ml of ammonia hydroxide dropwise over 25 minutes, influencing the nanoparticle size by regulating the solution's pH (a higher pH result in smaller particles). After this, the mixture is stirred for an additional four hours at the same temperature to allow the nanoparticles to form and grow. Once the reaction is complete, the nanoparticles are isolated by centrifugation at 4000 rpm to remove the liquid above the sedimented particles. The sample is washed four times with 96% ethanol to eliminate any residual impurities. The nanoparticles are then dried on a ceramic plate in an oven set to 80°C for six hours, a crucial step to maintain their magnetic properties and prevent phase changes. After drying, the nanoparticles are finely milled into a powder for further application or investigation. 2.3 Preparation of Nanocomposites: Nanoparticles were prepared and incorporated into the polymer solution, a crucial step for their effective distribution in the final nanofiber structure. After dissolving PET in a TFA: DCM solvent, nanopowders were added. Concentrations of PET (20 and 15 wt.%) and Fe 3 O 4 (1.5 wt.%) were precisely adjusted to ensure a balance between structural integrity and functional properties, with Fe 3 O 4 at 9 wt.% relative to PET. Samples were placed in a 5 mL syringe for electrospinning. The incorporation process was optimized to prevent particle aggregation, preserving the uniformity, surface morphology, and mechanical integrity of the nanofibers. 2.4 Electrospinning In the electrospinning process of PET/NPs solution, parameters like voltage, flow rate, and needle-to-collector distance are key for producing uniform nanofibers while preserving nanoparticle integrity. Both static vertical and dynamic horizontal setups are employed to optimize fiber formation around nanofillers. Static Vertical Electrospinning Setup in this method, a 5 mL syringe containing the PET/NPs solution is fixed vertically, and the flow rate is controlled by a microdialysis syringe pump. The syringe needle is connected to a high-voltage power supply (20 kV), while a plate collector captures the nanofibers at a flow rate of 15 µL/min and a needle-to-collector distance of 6 cm. The polymer solution stretches into nanofibers, which are deposited on the collector. Rotating Horizontal Electrospinning Setup the solution is placed in a syringe connected to a horizontal syringe pump. The positive electrode is linked to the syringe needle, and the negative electrode is attached to a drum collector rotating at 1000 rpm, covered with aluminum foil for easy removal of nanofibers. The electric field (20 kV) enables fiber formation at the same flow rate (15 µL/min) and a needle-to-collector distance of 10 cm, creating uniform nanofiber membranes with controlled thickness, high porosity, and tailored mechanical properties. 2.5 Post-Electrospinning Treatment After electrospinning, nanofiber membranes undergo post-treatment to stabilize nanoparticles within the fibers, preventing leaching in water purification. This involves heating at 80°C for one hour, enhancing nanoparticle migration into the polymer surface without compromising fiber integrity. Gradual cooling prevents thermal stress, ensuring mechanical strength and nanoparticle retention for effective purification. 2.6 Analysis Techniques 2.6.1 Differential Scanning Calorimeter (DSC) Differential Scanning Calorimetry (DSC) was used to analyze the thermal properties of PET samples. Around 3.0 mg samples were sealed in aluminum pans with a pinhole for gas exchange. The analysis was carried out under nitrogen to prevent oxidation, with a purge gas flow of 50 µL/min. Samples were heated from 30°C to 300°C at 10°C/min, allowing observation of thermal events like glass transitions, melting points, and crystallization behaviors. After holding at 300°C for 5 minutes, they were cooled back to 30°C at the same rate to capture any reversible transitions. The degree of crystallinity and other thermal properties were determined based on the thermograms generated by applying the following equation [ 12 ]. $$\:{X}_{C,DSC}=\frac{\varDelta\:{H}_{f}-\varDelta\:{H}_{c}}{\varDelta\:{H}_{f}^{^\circ\:}}$$ 1 Where \(\:{X}_{C,DSC}\) represents the degree of crystallinity, \(\:\varDelta\:{H}_{f}\) the enthalpy of fusion or heat, \(\:\varDelta\:{H}_{c}\) is the enthalpy of cold crystallization, signifies the heat of cold crystallization, both derived from the DSC thermograms. The standard enthalpy of fusion for fully crystalline PET is taken as 136 J·g − 1 assessed directly from DSC thermograms, and \(\:\varDelta\:{H}_{f}^{^\circ\:}\) (136 J·g − 1 ) is the enthalpy of fusion of 100% crystalline PET[ 13 ]. 2.6.2 Transmission Electron Microscope (TEM) The size and morphology of nanoparticles were analyzed using HRTEM on a JEOL JEM 2100 microscope. This advanced tool features a single crystal LaB6 cathode and adjustable acceleration voltages of 80kV-200kV. With a magnification range of 1,200X to 1,000,000X, it enables atomic-scale imaging at 0.27 nm resolution. 2.6.3 X-Ray Diffraction For XRD analysis of nanoparticle powders, the Panalytical Empyrean 3, from Malvern, Netherlands, is utilized, capable of analyzing a wide range of sample types including powders and nanomaterials. Equipped with Cu-Kα radiation (1.54060Å) at 30mA and 40kV. The crystalline size of the nanoparticles will be calculated using the Scherrer formula[ 14 ], $$\:D=\frac{k\lambda\:}{\beta\:\text{c}\text{o}\text{s}\theta\:}$$ 2 Where k is a dimensionless shape factor, λ is the x-ray wavelength, β is the line broadening at half the maximum intensity (FWHM), and θ is the Bragg angle [ 14 ]. 2.6.4 Field-Emission Scanning Electron Microscope (FE-SEM): Field-Emission Scanning Electron Microscopy (FE-SEM) with the Zeiss SUPRA 55-VP was used for high-resolution imaging and precise measurement of polymer nanofibers and embedded nanoparticles. Nonconductive samples were sputter-coated with gold to enhance conductivity. This enabled accurate calculations of fiber diameters and nanoparticle distribution within the nanofibers. 2.6.5 Mechanical Test : The In Situ Tensile Stage is designed for mechanical testing within an SEM, allowing real-time observation of sample deformation. However, in our tests conducted outside the SEM, the fibers went out of focus as they deformed, Therefore, tensile tests were performed separately. Tensile samples were prepared according to the recommended dimensions (Fig. 2 . a). Each fiber sample was tested three times to ensure accurate measurements. During testing, sample deformation was observed and the software generated force versus displacement graphs. These were converted into stress versus strain curves, incorporating the average thickness of the specimens, which was measured using a micrometer at five different locations per sample ( Table 1 ). Table 1. Thickness measurement of tensile samples Sample Thickness mm P10 0.022 ± 0.0003 P15 0.036 ± 0.004 P20 0.029 ± 0.002 P15F 0.039 ± 0.001 To compare the mechanical behavior of PET bottle materials before and after electrospinning, tensile strength and deformation were measured using a Zwick/Roell Z100 universal testing machine. Three samples were cut from the straight part of the PET water bottle, each with a thickness of 0.2 mm and a width of 3.9 mm (Fig. 2 .b). 2.6.6 Membrane Adsorption Efficiency Tests: To evaluate the copper ion removal efficiency of microfiber membranes, both with and without nanoparticles, experiments were conducted using a 1 mM CuSO 4 solution as the contaminant model. For this, 249.68 mg of copper sulfate pentahydrate was dissolved in deionized water to make 1 liter of solution, which was stirred for 3 hours to ensure uniform copper ion concentration. Microfiber membranes, sized 5x5 cm 2 and weighing 150–200 mg, were submerged in 100 mL of this solution for 120 minutes at room temperature. The quantification (q, in mg/g) of the membranes' adsorption capacity was achieved through the formula: $$\:q=\frac{{(C}_{o}-{C}_{e})\times\:V}{{M}_{abs}}$$ 3 Where \(\:{C}_{o}\) ​ and \(\:{C}_{e}\) ​ represent the initial and equilibrium concentrations of copper ions in mg L − 1 , V denotes the volume of the solution in liters, and \(\:{M}_{abs}\) is the mass of the adsorbing microfiber membrane in grams. This formula facilitated a direct comparison between the copper ion adsorption capacities of the pure and nanoparticle-incorporated microfiber membranes. All samples where tested further tested using an ICP test from Cu ions detection after filtration. 2.6.7 Inductively Coupled Plasma- Optical Emission Spectroscopy (ICP- OES): Metal ion concentrations are analyzed by first digesting samples in an acid solution using the Anton-Paar Multiwave PRO microwave digestion system [ 15 ]. The digested samples are then measured with the Agilent 5100 ICP-OES [ 16 ]. Calibration curves, including a blank and at least three standards, are created for each measurement series. The accuracy of the results is verified with external reference standards and quality control samples from NIST. This process follows the 2023 APHA guidelines for water quality analysis, ensuring compliance with best practices. 3 Results 3.1 Electrospinning The static vertical electrospinning setup produced unevenly distributed nanofibers, demonstrating dense areas and inconsistencies due to its stationary collector. In contrast, the rotating horizontal setup, with its dynamic drum collector, achieved uniform fiber distribution across the collector surface, significantly reducing density variations and improving control over mat characteristics like thickness and porosity. Figure 3 a and Fig. 3 b contrasts the outcomes of two electrospinning methods. The heat treatment at 80°C resulted in noticeable darkening of PET nanofiber films, indicating significant magnetite nanoparticle migration to the surface. This transformation highlights nanoparticle movement in response to thermal exposure below the polymer’s glass transition temperature, revealing interactions between polymer and nanoparticle dynamics. Figure 3 .c and Fig. 3 .d illustrates the before and after images of PET/Fe 3 O 4 films. 3.2 Analysis Techniques 3.2.1 Differential scanning calorimetry (DSC): The Differential scanning calorimetry (DSC) of PET and its nanofiber shown in Fig. 4 . The calculated crystallinity index (X c ) for the PET bottle was 1.169%, with the P10, P15, and P20 nanofibers crystallinity of 2.118%, 0.985%, and 4.971% respectively, Table 2. The melting temperatures (T m ) across all samples showed minimal variation. The DSC thermograms for PET and its nanocomposites exhibit distinctive double peaks, suggesting complex crystalline structures and morphologies. Table 2. Crystallinity of PET bottle and different polymer concentration samples H f J/g H c J/g X c,DSC (%) T m (°C) PET 39.35 37.76 1.169 248.79 P10 39.35 36.47 2.118 247.12 P15 35.16 36.5 0.985 246.44 P20 30.56 37.32 4.971 246.60 3.2.2 Transmission Electron Microscope (TEM) The magnetite nanoparticles exhibit a polydisperse size distribution, with diameters ranging from approximately 12 nm to over 30 nm. TEM images (Fig. 4 ) reveal significant aggregation, with particles forming clusters of varying sizes. The nanoparticle shapes vary from spherical to irregular, with a relatively smooth surface morphology despite the observed clustering. 3.2.3 X-Ray Diffraction The X-ray diffraction (XRD) analysis, shown in Fig. 6 , identified synthesized iron oxide nanoparticles as magnetite (Fe 3 O 4 ) using card No. 01-084-2782. Key peaks include 2θ = 35.5452° (d-spacing 2.52359 Å) for the (311) plane and 2θ = 62.8686° (d-spacing 1.47703 Å) for the (440) plane, with calculated crystal sizes of approximately 17 nm. Other notable peaks were observed at 2θ = 18.3847° and 30.2662° for the (111) and (220) planes, respectively. The average crystallite size was estimated at 19.7 ± 8.13 nm, aligning with TEM results. 3.2.4 Field-Emission Scanning Electron Microscope (FE-SEM): The microstructural analysis of PET films reveals key findings related to fiber concentration and its impact on fiber diameter and orientation, which are critical for mechanical and filtration properties. At 10 wt% concentration (Fig. 7 .a), the tightly packed fibers have an average diameter of (0.42 ± 0.03) µm with minimal angular deviation. Figure 7 .b illustrates this compact structure. At 15 wt.% concentration, fibers have an average diameter of (1.06 ± 0.08) µm with increased angular deviation, resulting in a more diverse orientation (Fig. 7 .c). At 20 wt.%, the diameter increases to (1.56 ± 0.28) µm, with broader angular deviation (Fig. 7 .d). The FE-SEM analysis of P15F films, before and after heat treatment, revealed key morphological changes. Before treatment (Fig. 7 . e ), the PET/Fe 3 O 4 film exhibited a smooth surface with well-dispersed nanoparticles (Fig. 7 . f ). Post-treatment at 80°C (Fig. 7 . g ), significant nanoparticle migration towards the surface was observed, leading to rougher textures and heterogeneous nanoparticle distribution. Higher magnification images (Fig. 7 . h ) confirmed increased nanoparticle visibility and surface density post-heat treatment, without compromising the fibers' structural integrity. 3.2.5 Mechanical Test: The mechanical properties of PET bottles, as shown in Table 3 . PET microfibers produced at different concentrations (P10, P15, P20) exhibit varying mechanical properties. P10 fibers show a UTS of 66 ± 5 MPa, P15 fibers 47 ± 2 MPa, and P20 fibers 31 ± 1 MPa. While P15 fibers show a moderate mechanical integrity and a significant elongation at break of 162 ± 7%, the introduction of Fe 3 O 4 nanoparticles in P15F results in a UTS of 86 ± 10 MPa, with a reduction in elongation to 31 ± 5% and toughness to 28 ± 5 MJ/m³. Figure 8 shows the Stress vs. Strain curves for PET bottles and nanofibers at different concentrations. Table 3 Mechanical Properties of the PET bottle and nanofibers P10 P15 P20 P15F PET Bottle UTS (MPa) 66 ± 5 47 ± 2 31 ± 1 86 ± 10 121 ± 10 El% 58 ± 12 162 ± 7 54 ± 7 31 ± 5 34.8 ± 3.3 Elastic Modules (GPa) 0.75 ± 0.22 0.68 ± 1 0.37 ± 0.19 1 ± 0.14 3684 ± 95 Toughness MJ/m3 34 ± 8 63 ± 1 13 ± 2 28 ± 5 24.6 ± 11 3.2.6 Membrane Adsorption Efficiency Tests: Table 4 shows the adsorption test results for PET fibers with 1mM Cu²⁺ ions. The lower concentration PET fibers exhibit an adsorption capacity of 12 mg/g. P15 fibers show a slightly lower adsorption capacity of 11.1 mg/g, while P20 fibers have a further reduced capacity of 6 mg/g. The addition of Fe 3 O 4 nanoparticles to P15 significantly enhances adsorption capacity to 19.9 mg/g. Fe 3 O 4 improves adsorption in P20 fibers, but not as effectively as in P15F. Table 4 Adsorption Test Results on all PET Samples with Co of 1mM Cu Sample Q Adsorption Capacity mg/cm 2 Q Adsorption Capacity mmol/g Q Adsorption Capacity mg/g P10 0.09 0.19 12 P15 0.06 0.17 11.1 P20 0.05 0.09 6 P15F 0.11 0.31 19.9 P20F 0.08 0.2 12.8 4 Discussion In the discussion of PET nanofibers synthesized through various electrospinning setups, post-electrospinning treatments, and characterization techniques, the focus is on optimizing fiber properties for water filtration applications. This section investigates how the electrospinning process, nanoparticle integration, and thermal treatments influence nanofiber morphology and functionality, with the aim of enhancing environmental remediation efforts. The static vertical electrospinning setup produces nanofibers with a non-uniform distribution, as dense fiber accumulation occurs due to the absence of dynamic substrate movement. This can be problematic for filtration applications that require uniform fiber distribution to ensure consistent pore sizes throughout the material. In contrast, the rotating horizontal electrospinning process, which uses a dynamic drum collector, achieves more uniform nanofiber distribution due to the drum's continuous motion, allowing for layer-by-layer deposition and minimal fiber accumulation (Fig. 3 .b). This uniformity is crucial for applications where consistent fiber distribution is paramount. Post-electrospinning heat treatment reveals significant insights into nanoparticle behavior within the polymer matrix. The observed migration of magnetite nanoparticles to the surface of PET nanofibers during heat treatment below the T g at 80 C° challenges conventional understanding of polymer dynamics. Even below the T g , polymers exhibit sufficient segmental mobility to allow for nanoparticle migration, suggesting that traditional views on polymer behavior at the nanoscale need adjustment [ 17 ]. This enhanced surface roughness and altered nanoparticle distribution increase the functional surface area, potentially improving the adsorption properties of the fibers for filtration applications. Differential Scanning Calorimetry (DSC) analyses the thermal properties of the nanofibers. DSC showed no significant variations across different polymer concentrations in thermal transitions related to the crystallinity index (X c ) of the nanofibers, indicating that polymer concentration does not substantially affect melting temperatures (T m ). However, The DSC thermograms for PET nanofibers exhibit distinctive double peaks, suggesting complex crystalline structures and morphologies (Fig. 4 ). This phenomenon is likely due to the high surface-to-volume ratio in nanofibers and the rapid cooling during electrospinning, which induces non-equilibrium states and varied lamellar thicknesses. Such behavior aligns with theories on dual morphology and recrystallization-remelt mechanisms, which explain the diverse melting behaviors observed in nanofibers compared to bulk materials. This is consistent with the literature, as multiple melting behaviors in PET, influenced by factors like lamellar thickening and reorganization during heating, have been previously reported by Kong and Hay and Woo and Ko [ 18 ], [ 19 ]. TEM analysis revealed a polydisperse size distribution for Fe 3 O 4 nanoparticles, with particle sizes ranging from approximately 12 nm to over 30 nm. The nanoparticles showed a tendency to aggregate, forming clusters. These aggregates may reduce the effective surface area available for adsorption in filtration membranes. XRD analysis confirmed the crystallographic structure of the synthesized Fe 3 O 4 nanoparticles, with distinct peaks corresponding to the magnetite phase. The average crystal size was around 17 nm, aligning with the TEM results. The uniformity of particle size and structure suggests a consistent synthesis process. Field-Emission Scanning Electron Microscopy (FE-SEM) studies the modifications in PET nanofibers due to varied polymer concentrations and thermal processing. Increasing the polymer content from 10 wt% to 20 wt% leads to an increase in fiber thickness, transitioning from a dense, finely structured arrangement to a looser configuration with thicker fibers. This structural modification significantly improves the mats' permeability by enlarging the inter-fiber pore spaces, potentially enhancing filtration efficiency but possibly reducing the fibers' mechanical strength. Additionally, heat treatments conducted below the glass transition temperature, promote the migration of magnetite nanoparticles towards the surfaces of the fibers. This alteration not only roughens the fiber surfaces but also differentiates the nanoparticle distribution across them, thus enhancing their properties for adsorption and catalytic activity. Such enhancements are crucial for the effective deployment of nanofibers in advanced purification systems, where optimal surface properties are critical for interacting with and removing contaminants. The mechanical properties of PET nanofibers varied significantly with polymer concentration. At 10 wt%, PET nanofibers exhibited high tensile strength (UTS of 66 ± 5 MPa) and moderate ductility, making them suitable for high-pressure filtration applications. At 15 wt%, the nanofibers demonstrated increased ductility and toughness, which could be advantageous for filtration applications requiring materials that withstand dynamic stresses. When comparing our PET nanofibers to those reported in the literature for recycled PET [ 13 ], several notable differences emerge. Our P10 fibers, outperform the reference's 1.0 µm fibers, highlighting the efficacy of our production method at this concentration. Although our P15 fibers exhibit a lower UTS of 47 ± 2 MPa compared to the 62.5 MPa reported for similar fibers, they show a significantly higher elongation at break of 162 ± 7%. This indicates that our P15 fibers offer greater flexibility, a crucial characteristic for filtration applications where materials must adapt to various stresses. The addition of F e 3O 4 nanoparticles in the P15F samples further enhanced tensile strength (UTS of 86 ± 10 MPa) but reduced ductility and toughness, highlighting a trade-off between strength and flexibility. This trade-off is a recognized phenomenon in composite materials, where increased filler content can enhance yield strength at the cost of ductility and energy adsorption capacity, as described in previous studies[ 20 ] The adsorption efficiency of PET nanofibers was tested using a 1mM Cu²⁺ solution. At lower polymer concentrations (P10), the nanofibers demonstrated a high adsorption capacity (0.19 mmol/g), likely due to the increased surface area available for adsorption. As fiber diameter increased in the P15 and P20 samples, adsorption capacity decreased slightly due to the reduction in surface-to-volume ratio. Compared to a previous study where they reached a Cu (II) adsorption capacity of 0.06 mmol/g for similar PET electrospun nanofiber membrane[ 21 ]. However, the incorporation of Fe 3 O 4 nanoparticles significantly enhanced adsorption capacity in the P15F samples (0.31 mmol/g), indicating that the magnetic properties of Fe 3 O 4 improve the material's ability to remove heavy metals from water. In previous study, they reached an adsorption capacity of Fe 3 O 4 for Cu(II) 0.160 mmol g − 1 [ 22 ], making the current findings superior for both PET nanofibers and nanocomposites, compared to previously reported results. 5 Conclusion This research represents a step forward in water purification technologies by repurposing recycled Polyethylene Terephthalate (PET) bottles into advanced purification membranes. These membranes are enhanced through the incorporation of metal nanoparticles, particularly Iron Oxide (Fe 3 O 4 ), to significantly enhance their water treatment capabilities. Optimized electrospinning produced uniform PET nanofibers, critical for efficient filtration. Incorporating Fe 3 O 4 ensured stable and evenly distributed nanoparticles, with heat treatments promoting their migration to the fiber surface, providing valuable insights for tailoring nanocomposites. Characterization techniques, including TEM, XRD, and FE-SEM, confirmed the nanofibers' structural and morphological attributes, with Fe 3 O 4 nanoparticles exhibiting a size range of 12–30 nm. Thermal and mechanical testing showed that fibers with 10 wt.% polymer concentration achieved the highest tensile strength (66 MPa), while 15 wt.% concentration improved ductility (162%). Adding Fe 3 O 4 nanoparticles boosted tensile strength to 86 MPa, though with reduced flexibility, demonstrating the balance required in nanoparticle-enhanced fibers. Adsorption tests revealed that Fe₃O₄-infused PET membranes significantly improved contaminant removal, achieving a capacity of 19.8 mg/g, attributed to the nanoparticles' high surface energy and affinity for heavy metals. Future research should investigate the use of advanced nanoparticles like TiO₂, Ag, ZnO, and graphene oxide for their superior adsorptive and antibacterial properties. Exploring innovative electrospinning techniques and post-treatment processes can further enhance membrane performance. Field testing and environmental impact assessments are crucial to ensure these technologies are scalable, sustainable, and effective for real-world water purification applications. Declarations Ethics, Consent to Participate, and Consent to Publish Declarations: Not applicable. Clinical Trial Registration Details: Not applicable. Funding: No funding was received for conducting this study. Competing Interests: The authors declare that they have no competing financial or non-financial interests. Author Contributions: All authors contributed to the conception and design. Material preparation, data collection, and analysis were performed by Amira Hassan. The manuscript draft was prepared by Amira Hassan and critically revised by all authors. All authors read and approved the final manuscript. Compliance with Ethical Standards: This article does not contain any studies involving human or animal subjects. Data Availability Statement: The datasets generated during and/or analyzed during the current study are available from the corresponding author upon reasonable request. References Ali EM, El-Shehawy AS (2023) Metallic Nanoparticles and Bioremediation for Wastewater Treatment. In: Shah MP (ed) Advanced Application of Nanotechnology to Industrial Wastewater. Springer Nature Singapore, Singapore, pp 215–239. https://doi.org/10.1007/978-981-99-3292-4_11 Mishra S, Chowdhary P, Bharagava RN (2019) Conventional Methods for the Removal of Industrial Pollutants, Their Merits and Demerits. In: Bharagava RN, Chowdhary P (eds) Emerging and Eco-Friendly Approaches for Waste Management. Springer Singapore, Singapore, pp 1–31. https://doi.org/10.1007/978-981-10-8669-4_1 Rath ME, Choi SY, Sayoc J, Shin J, Hong SG, Park JY (2019) Validation of Nanoparticle Tracking Analysis in Characterizing Extracellular Vesicle Isolated from Polydisperse Biological Samples. FASEB J 33(lb599). https://doi.org/10.1096/fasebj.2019.33.1_supplement.lb599 Ji K, et al (2023) Research Progress of Water Treatment Technology Based on Nanofiber Membranes. Polymers 15(3). https://doi.org/10.3390/polym15030741 Salunkhe HJ, et al (2020) Role of Nanotechnology to Control Water Pollution. International Journal of Researches in Biosciences, Agriculture and Technology. Available: www.ijrbat.in Mariana M, et al (2022) Recent trends and future prospects of nanostructured aerogels in water treatment applications. J Water Process Eng 45:102481. https://doi.org/10.1016/J.JWPE.2021.102481 Zhang Y, Wang F, Wang Y (2021) Recent developments of electrospun nanofibrous materials as novel adsorbents for water treatment. Mater Today Commun 27:102272. https://doi.org/10.1016/J.MTCOMM.2021.102272 Gee S, Johnson B, Smith AL (2018) Optimizing electrospinning parameters for piezoelectric PVDF nanofiber membranes. J Memb Sci 563:804–812. https://doi.org/10.1016/j.memsci.2018.06.050 T. M. S. et al (2021) A review of recent progress in polymeric electrospun nanofiber membranes in addressing safe water global issues. RSC Adv 11(16):9638–9663. https://doi.org/10.1039/D1RA00060H Jannah NR, Onggo D (2019) Synthesis of Fe 3 O 4 nanoparticles for colour removal of printing ink solution. J Phys Conf Ser 1245. https://doi.org/10.1088/1742-6596/1245/1/012040 Hossain MT, Shahid MA, Ali A (2022) Development of nanofibrous membrane from recycled polyethene terephthalate bottle by electrospinning. OpenNano 8:100089. https://doi.org/10.1016/j.onano.2022.100089 Sichina WJ (2000) DSC as Problem Solving Tool: Measurement of Percent Crystallinity of Thermoplastics. Available: www.perkinelmer.com Strain IN, Wu Q, Pourrahimi AM, Hedenqvist MS, Olsson RT, Andersson RL (2015) Electrospinning of recycled PET to generate tough mesomorphic fibre membranes for smoke filtration. J Mater Chem A Mater 3(4):1632–1640. https://doi.org/10.1039/c4ta06191h Hossain MT, Hossain MM, Begum MHA, Shahjahan M, Islam MM, Saha B (2018) Magnetite (Fe 3 O 4 ) nanoparticles for chromium removal. Bangladesh J Sci Ind Res 53(3):219–224. https://doi.org/10.3329/bjsir.v53i3.38269 Anton Paar Multiwave 5000. https://www.anton-paar.com/se-en/products/details/multiwave-5000/ Agilent 5100 ICP-OES Technical Overview. What is Synchronous Vertical Dual View (SVDV). www.agilent.com Qu T, et al (2023) Structure–Property Relationship, Glass Transition, and Crystallization Behaviors of Conjugated Polymers. Polymers 15(21):4268. https://doi.org/10.3390/polym15214268 Kong Y, Hay JN Multiple melting behaviour of poly(ethylene terephthalate). Available: www.elsevier.com/locate/polymer Woo EM, Ko TY (1996) A differential scanning calorimetry study on poly(ethylene terephthalate) isothermally crystallized at stepwise temperatures: multiple melting behavior re-investigated. Colloid Polym Sci 274. https://doi.org/10.1007/BF00652396 Matthews FL, Rawlings RD (1999) Reinforcements and the reinforcement–matrix interface. In: Composite Materials. pp 29–77. https://doi.org/10.1016/B978-1-85573-473-9.50005-9 Totito TC, Laatikainen K, Pereao O, Bode-Aluko C, Petrik L (2021) Adsorptive Recovery of Cu2+ from Aqueous Solution by Polyethylene Terephthalate Nanofibres Modified with 2-(Aminomethyl)Pyridine. Appl Sci 11(24):11912. https://doi.org/10.3390/app112411912 Giraldo L, Erto A, Moreno-Piraján JC (2013) Magnetite nanoparticles for removal of heavy metals from aqueous solutions: synthesis and characterization. Adsorption 19(2):465–474. https://doi.org/10.1007/s10450-012-9468-1 Additional Declarations No competing interests reported. Cite Share Download PDF Status: Published Journal Publication published 05 Aug, 2025 Read the published version in Discover Materials → Version 1 posted Editorial decision: Revision requested 17 Jun, 2025 Reviews received at journal 15 Jun, 2025 Reviews received at journal 14 Jun, 2025 Reviewers agreed at journal 13 Jun, 2025 Reviewers agreed at journal 06 Jun, 2025 Reviewers invited by journal 06 Jun, 2025 Editor invited by journal 02 Jun, 2025 Editor assigned by journal 28 May, 2025 Submission checks completed at journal 28 May, 2025 First submitted to journal 25 May, 2025 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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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-6745323","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":467668468,"identity":"4d42132d-c4a5-4e89-ad97-84534eb3b491","order_by":0,"name":"Amira Hassan","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA4UlEQVRIiWNgGAWjYFACxgYQArMeJJCqhdmASC0QXSDAJkGUav5ph9s+/NxhZy/ffvZYxYMKGzkG9t7HL/Bpkbid2Dyz90xy4oYzeWk3Es6kGTPwHDezwGsNUAsDbxtzggFDjtmNxLbDiQ0SaWwG+HTIA7Uw/m2rt5fvf2NWkPjvfz1BLQZALcy8bYcZG27kmDEkNhxIYJBIY36AT4shSIts2/HEDTfeGEskHEs2bOM5xobXK3K30x8zvm2rBjosx/Djjxo7eX72NuYPePVgADaiIwgZkGrLKBgFo2AUDHMAACvgSm7lY4gfAAAAAElFTkSuQmCC","orcid":"","institution":"German University in Cairo","correspondingAuthor":true,"prefix":"","firstName":"Amira","middleName":"","lastName":"Hassan","suffix":""},{"id":467668469,"identity":"6b36b6c9-cb4f-4c10-822f-2df1d5bd4a25","order_by":1,"name":"Ahmed Abd El-Aziz","email":"","orcid":"","institution":"German University in Cairo","correspondingAuthor":false,"prefix":"","firstName":"Ahmed","middleName":"Abd","lastName":"El-Aziz","suffix":""},{"id":467668470,"identity":"4888ddc7-cd0f-4e08-a519-e274f24d4bb8","order_by":2,"name":"Moahmed ELwi","email":"","orcid":"","institution":"German University in Cairo","correspondingAuthor":false,"prefix":"","firstName":"Moahmed","middleName":"","lastName":"ELwi","suffix":""},{"id":467668471,"identity":"d80c1906-4e39-4155-960f-5bd2d831ae34","order_by":3,"name":"Anke Klingner","email":"","orcid":"","institution":"German University in Cairo","correspondingAuthor":false,"prefix":"","firstName":"Anke","middleName":"","lastName":"Klingner","suffix":""}],"badges":[],"createdAt":"2025-05-25 18:53:13","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-6745323/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-6745323/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.1007/s43939-025-00343-2","type":"published","date":"2025-08-05T15:58:08+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":84306376,"identity":"cfa7c053-4638-456e-9507-a45128de4ffd","added_by":"auto","created_at":"2025-06-10 11:24:47","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":1119383,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eSchematic illustration represents the transformation of recycled PET bottles with incorporated NPs into functional nanocomposite filters.\u003c/strong\u003e\u003c/p\u003e","description":"","filename":"1.png","url":"https://assets-eu.researchsquare.com/files/rs-6745323/v1/ba38bb2a61a473405f037117.png"},{"id":84306370,"identity":"cd429d17-06f8-4e28-bee9-dc9d814bd34a","added_by":"auto","created_at":"2025-06-10 11:24:46","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":345586,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003ea) Standard Sample dimensions for the micro-tensile stage in mm, b) PET bottle Tensile samples\u003c/strong\u003e\u003c/p\u003e","description":"","filename":"2.png","url":"https://assets-eu.researchsquare.com/files/rs-6745323/v1/814ac21e7d27e9e8a6fbc5ec.png"},{"id":84306311,"identity":"2efd54e4-6e8f-4f5d-b837-7c47cd24b489","added_by":"auto","created_at":"2025-06-10 11:24:44","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":1467533,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003ea) Static vertical electrospinning process resulting in a varied density in nanofiber accumulation. b) Uniform Nanofiber Film Resulted from Dynamic Rotating Electrospinning, c) PET/\u003c/strong\u003e \u003cstrong\u003eFe\u003c/strong\u003e\u003csub\u003e\u003cstrong\u003e3\u003c/strong\u003e\u003c/sub\u003e\u003cstrong\u003eO\u003c/strong\u003e\u003csub\u003e\u003cstrong\u003e4\u003c/strong\u003e\u003c/sub\u003e \u003cstrong\u003eNanofiber Film Pre, d) PET/\u003c/strong\u003e \u003cstrong\u003eFe\u003c/strong\u003e\u003csub\u003e\u003cstrong\u003e3\u003c/strong\u003e\u003c/sub\u003e\u003cstrong\u003eO\u003c/strong\u003e\u003csub\u003e\u003cstrong\u003e4\u003c/strong\u003e\u003c/sub\u003e \u003cstrong\u003eNanofiber Film Post Heat Treatment.\u003c/strong\u003e\u003c/p\u003e","description":"","filename":"3.png","url":"https://assets-eu.researchsquare.com/files/rs-6745323/v1/6af36d50956fef9985e16097.png"},{"id":84306369,"identity":"088eccde-d4bc-45bd-9f4a-fb17eb06e7b9","added_by":"auto","created_at":"2025-06-10 11:24:46","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":148790,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eDSC analysis on PET bottle and different polymer concentration.\u003c/strong\u003e\u003c/p\u003e","description":"","filename":"4.png","url":"https://assets-eu.researchsquare.com/files/rs-6745323/v1/85a2de0389520b0ffb9e87c3.png"},{"id":84306259,"identity":"45a1d54e-11e1-42df-968a-c58fea3ec5dc","added_by":"auto","created_at":"2025-06-10 11:24:41","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":2006747,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eTEM images of Fe\u003c/strong\u003e\u003csub\u003e\u003cstrong\u003e3\u003c/strong\u003e\u003c/sub\u003e\u003cstrong\u003eO\u003c/strong\u003e\u003csub\u003e\u003cstrong\u003e4\u003c/strong\u003e\u003c/sub\u003e\u003cstrong\u003e Nanoparticles.\u003c/strong\u003e\u003c/p\u003e","description":"","filename":"5.png","url":"https://assets-eu.researchsquare.com/files/rs-6745323/v1/fd3dba8b35b6da5beb02c1b3.png"},{"id":84306291,"identity":"71186218-1280-4715-a828-ff05bc06b7fa","added_by":"auto","created_at":"2025-06-10 11:24:43","extension":"png","order_by":6,"title":"Figure 6","display":"","copyAsset":false,"role":"figure","size":305466,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eXRD analysis results of Fe\u003c/strong\u003e\u003csub\u003e\u003cstrong\u003e3\u003c/strong\u003e\u003c/sub\u003e\u003cstrong\u003eO\u003c/strong\u003e\u003csub\u003e\u003cstrong\u003e4\u003c/strong\u003e\u003c/sub\u003e \u003cstrong\u003eNanoparticles.\u003c/strong\u003e\u003c/p\u003e","description":"","filename":"6.png","url":"https://assets-eu.researchsquare.com/files/rs-6745323/v1/c6723c8b6c8868348244fc5a.png"},{"id":84306297,"identity":"2b1071a5-c83f-4ddb-b4e2-397a43fef9b5","added_by":"auto","created_at":"2025-06-10 11:24:43","extension":"png","order_by":7,"title":"Figure 7","display":"","copyAsset":false,"role":"figure","size":5306204,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eSEM images of a) P10 sample demonstrating different fiber diameters, b) P10 sample closed packed structure. c) P15 sample, d) P20 Sample, e) P15F Film Pre-heat treatment, f) P15F Film Pre-heat treatment at higher magnification, g) P15F Film Post-heat treatment, h) P15F Film post-heat treatment at higher magnification.\u003c/strong\u003e\u003c/p\u003e","description":"","filename":"7.png","url":"https://assets-eu.researchsquare.com/files/rs-6745323/v1/cf570a0cdaf5e5f1dc079555.png"},{"id":84306278,"identity":"6cae6eb0-45d8-407a-81b5-372888e5bd9e","added_by":"auto","created_at":"2025-06-10 11:24:42","extension":"png","order_by":8,"title":"Figure 8","display":"","copyAsset":false,"role":"figure","size":233869,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eStress vs. Strain Curves for a) P10, b) P15, c) P20, d) P15F\u003c/strong\u003e\u003c/p\u003e","description":"","filename":"8.png","url":"https://assets-eu.researchsquare.com/files/rs-6745323/v1/4aec549e2102f9d0570fa33d.png"},{"id":88814850,"identity":"e6c28b05-317b-4e2d-9136-8b3075d4caf3","added_by":"auto","created_at":"2025-08-11 16:10:08","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":15968074,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-6745323/v1/d0773068-0604-4485-aa18-2e5b7eb44490.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Fabrication and Characterization of Nano-loaded Recycled Materials for Water Purification, Part I: Iron Oxide Nanoparticles Incorporation ","fulltext":[{"header":"1 Introduction","content":"\u003cp\u003eWhile over 70% of Earth's surface is covered by water, only 0.5% is fresh water. Egypt is particularly vulnerable to water scarcity, a situation worsened by rapid population growth and industrialization, leading to increased freshwater demand. This could result in a significant water deficit in Africa, estimated at 28\u0026ndash;47% by 2030 [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e]. Furthermore, water scarcity affects societal living standards and development opportunities [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e]. The challenge of securing clean water is a critical global issue [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e], [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e]. The inadequacy of water treatment capacities in many regions [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e] underscores the need for advanced water treatment techniques.[\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e]. Adding to the water scarcity crisis is the devastating impact of water pollution on both human health and the environment. It leads to the death of approximately 14,000 people daily [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e], primarily due to untreated sewage contaminating drinking water in developing countries. This pollution affects aquatic ecosystems, reducing biodiversity and harming fish populations, which are crucial for human consumption[\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eWhile traditional methods like oxidation, electrocoagulation, and chlorination are used [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e], they are often inefficient and environmentally harmful. Membrane technology, on the other hand, offers several advantages in water treatment, including no secondary contaminants, high selectivity, efficiency, and stability [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]. Techniques like microfiltration, ultrafiltration, nanofiltration, and reverse osmosis are part of this technology, proving effective in water separation and purification [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]. The performance of these membrane technologies is greatly influenced by the choice of materials and their preparation methods[\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eThe urgent need for efficient water treatment is further compounded by the widespread presence of pollutants. Water pollution, primarily caused by organic or inorganic solutes and heavy metals like Hg, Cu, As, Cr, Zn, Pb, and Cd, is a significant global issue exacerbated by human activities and industrial processes. This pollution alters water's characteristics and quality, necessitating efficient treatment before community use. The increasing need for better water management and sustainable practices has led to a demand for advanced technologies. Nanoscience and nanotechnology are recognized for their potential to enhance environmentally friendly technologies for controlling water pollution[\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e], [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eNanofiber membranes, due to their large surface area, high porosity, ease of modification, and compatibility with other materials, show great potential in addressing water pollution issues [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e], [\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e]. Electrospinning, a method for producing nanofibers from polymers, has gained attention for its simplicity and effectiveness [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e], [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e]. These electrospun nanofiber membranes exhibit enhanced performance in water treatment, overcoming limitations of traditional membranes such as low permeation flux and poor antifouling properties [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e], [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e]. Consequently, research focusing on electrospinning technology to develop nanofiber membranes with high flux, superior antifouling, mechanical qualities, and microporous penetrability for water treatment is increasingly popular [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e], [\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eThe effectiveness of nanoparticles in water filtration is significantly enhanced by their unique properties. Metallic nanoparticles, such as noble metals and iron, have notable characteristics like surface Plasmon resonance, magnetic and optical polarizability, and thermal conductivity. These properties lead to diverse applications in various industries, including water treatment [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e]. Fe\u003csub\u003e3\u003c/sub\u003eO\u003csub\u003e4\u003c/sub\u003e nanoparticles are widely used as an adsorbent for water purification from contaminants. The synthesis of Fe\u003csub\u003e3\u003c/sub\u003eO\u003csub\u003e4\u003c/sub\u003e nanoparticles has been developed with various methods such as coprecipitation, solgel, hydrothermal, electrochemical, and microemulsion[\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e]. The coprecipitation method is the most commonly method since it is easy and efficient for the synthesis of Fe\u003csub\u003e3\u003c/sub\u003eO\u003csub\u003e4\u003c/sub\u003e nanoparticles[\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e]. Several studies used Fe\u003csub\u003e3\u003c/sub\u003eO\u003csub\u003e4\u003c/sub\u003e nanoparticles for metals adsorption such as arsenic[\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e], lead and chromium[\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eThis focus on advanced materials and technologies extends to addressing the environmental challenges posed by plastic waste, particularly PET bottles. Global consumption of PET bottles has surged to 481.6\u0026nbsp;billion annually, raising significant concerns about their environmental impact [\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e]. Recycling PET bottles has become critical for environmental sustainability, as their non-biodegradable components contribute to ecosystem degradation. In this context, the use of electrospinning to create nanofibrous membranes from recycled PET bottles have emerged as a promising approach to mitigate environmental burdens and transform waste into valuable resources [\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e]. The abundance and affordability of PET scrap materials, coupled with the challenges of recycling, have further driven this innovative recycling effort [\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eThis study aims to enhance global health and environmental protection by developing efficient, sustainable water purification technologies. Through the integration of Fe\u003csub\u003e3\u003c/sub\u003eO\u003csub\u003e4\u003c/sub\u003e nanoparticles within recycled electrospun PET nanofibers at varying polymer concentrations to innovate electrospun nanocomposites that function as water purifier. Concluded with various characterization techniques, the efficiency of these filters is thoroughly evaluated. Figure\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e. illustrates the main stages of the study.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e"},{"header":"2 Materials and Methods","content":"\u003cp\u003eThe PET nanofibers were synthesized utilizing recycled PET materials derived from Nestle water bottles. For the dissolution process of PET flakes, Trifluoroacetic acid (TFA) with a 99% purity level, acquired from Advent, India, and Dichloromethane (DCM) sourced from Power Chemical Egypt, Cairo. Iron (II) sulfate heptahydrate (FeSO\u003csub\u003e4\u003c/sub\u003e\u0026middot;7H\u003csub\u003e2\u003c/sub\u003eO) and Iron (III) chloride tetrahydrate (FeCl\u003csub\u003e2\u003c/sub\u003e\u0026middot;4H\u003csub\u003e2\u003c/sub\u003eO) from Sigma-Aldrich were used for Fe\u003csub\u003e3\u003c/sub\u003eO\u003csub\u003e4\u003c/sub\u003e nanoparticle synthesis. Ammonia hydroxide (25%) from Power Chemical Egypt, Cairo, was added to adjust pH.\u003c/p\u003e \u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003e2.1 Polymeric Nanofibers (Recycled PET Bottles):\u003c/h2\u003e \u003cp\u003eThe process begins by collecting Nestle water bottles, which are manually cut into flakes. These flakes are cleaned with ethanol to remove contaminants and then dried to eliminate moisture. This preparation ensures the PET material is ready for electrospinning. The PET flakes are dissolved in a solvent mixture of trifluoroacetic acid (TFA) and dichloromethane (DCM) in a 1:4 ratio to create polymer solutions at three different concentrations: 10 wt.%, 15 wt.%, and 20 wt.%. The solution is allowed to sit for 24 hours at room temperature to ensure complete dissolution. A magnetic stirrer is then used for one hour to ensure uniformity, which is crucial for producing consistent nanofibers.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec4\" class=\"Section2\"\u003e \u003ch2\u003e2.2 Preparation of Fe\u003csub\u003e3\u003c/sub\u003eO\u003csub\u003e4\u003c/sub\u003e Nanoparticles:\u003c/h2\u003e \u003cp\u003eFour grams Iron(II) sulfate heptahydrate (FeSO\u003csub\u003e4\u003c/sub\u003e\u0026middot;7H\u003csub\u003e2\u003c/sub\u003eO) and 8 grams Iron(III) chloride tetrahydrate (FeCl\u003csub\u003e2\u003c/sub\u003e\u0026middot;4H\u003csub\u003e2\u003c/sub\u003eO) are dissolved in 400 ml of deionized water to form the starting solution for magnetite nanoparticles. The solution is subsequently heated to 60\u0026deg;C and stirred for half an hour, allowing the salts to fully dissolve in preparation for nanoparticle formation. The growth phase begins with the addition of 25 ml of ammonia hydroxide dropwise over 25 minutes, influencing the nanoparticle size by regulating the solution's pH (a higher pH result in smaller particles). After this, the mixture is stirred for an additional four hours at the same temperature to allow the nanoparticles to form and grow. Once the reaction is complete, the nanoparticles are isolated by centrifugation at 4000 rpm to remove the liquid above the sedimented particles. The sample is washed four times with 96% ethanol to eliminate any residual impurities. The nanoparticles are then dried on a ceramic plate in an oven set to 80\u0026deg;C for six hours, a crucial step to maintain their magnetic properties and prevent phase changes. After drying, the nanoparticles are finely milled into a powder for further application or investigation.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec5\" class=\"Section2\"\u003e \u003ch2\u003e2.3 Preparation of Nanocomposites:\u003c/h2\u003e \u003cp\u003eNanoparticles were prepared and incorporated into the polymer solution, a crucial step for their effective distribution in the final nanofiber structure. After dissolving PET in a TFA: DCM solvent, nanopowders were added. Concentrations of PET (20 and 15 wt.%) and Fe\u003csub\u003e3\u003c/sub\u003eO\u003csub\u003e4\u003c/sub\u003e (1.5 wt.%) were precisely adjusted to ensure a balance between structural integrity and functional properties, with Fe\u003csub\u003e3\u003c/sub\u003eO\u003csub\u003e4\u003c/sub\u003e at 9 wt.% relative to PET. Samples were placed in a 5 mL syringe for electrospinning. The incorporation process was optimized to prevent particle aggregation, preserving the uniformity, surface morphology, and mechanical integrity of the nanofibers.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec6\" class=\"Section2\"\u003e \u003ch2\u003e2.4 Electrospinning\u003c/h2\u003e \u003cp\u003eIn the electrospinning process of PET/NPs solution, parameters like voltage, flow rate, and needle-to-collector distance are key for producing uniform nanofibers while preserving nanoparticle integrity. Both static vertical and dynamic horizontal setups are employed to optimize fiber formation around nanofillers.\u003c/p\u003e \u003cp\u003e \u003cstrong\u003eStatic Vertical Electrospinning Setup\u003c/strong\u003e \u003cp\u003ein this method, a 5 mL syringe containing the PET/NPs solution is fixed vertically, and the flow rate is controlled by a microdialysis syringe pump. The syringe needle is connected to a high-voltage power supply (20 kV), while a plate collector captures the nanofibers at a flow rate of 15 \u0026micro;L/min and a needle-to-collector distance of 6 cm. The polymer solution stretches into nanofibers, which are deposited on the collector.\u003c/p\u003e \u003c/p\u003e \u003cp\u003e \u003cstrong\u003eRotating Horizontal Electrospinning Setup\u003c/strong\u003e \u003cp\u003ethe solution is placed in a syringe connected to a horizontal syringe pump. The positive electrode is linked to the syringe needle, and the negative electrode is attached to a drum collector rotating at 1000 rpm, covered with aluminum foil for easy removal of nanofibers. The electric field (20 kV) enables fiber formation at the same flow rate (15 \u0026micro;L/min) and a needle-to-collector distance of 10 cm, creating uniform nanofiber membranes with controlled thickness, high porosity, and tailored mechanical properties.\u003c/p\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec7\" class=\"Section2\"\u003e \u003ch2\u003e2.5 Post-Electrospinning Treatment\u003c/h2\u003e \u003cp\u003eAfter electrospinning, nanofiber membranes undergo post-treatment to stabilize nanoparticles within the fibers, preventing leaching in water purification. This involves heating at 80\u0026deg;C for one hour, enhancing nanoparticle migration into the polymer surface without compromising fiber integrity. Gradual cooling prevents thermal stress, ensuring mechanical strength and nanoparticle retention for effective purification.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec8\" class=\"Section2\"\u003e \u003ch2\u003e2.6 Analysis Techniques\u003c/h2\u003e \u003cdiv id=\"Sec9\" class=\"Section3\"\u003e \u003ch2\u003e2.6.1 Differential Scanning Calorimeter (DSC)\u003c/h2\u003e \u003cp\u003eDifferential Scanning Calorimetry (DSC) was used to analyze the thermal properties of PET samples. Around 3.0 mg samples were sealed in aluminum pans with a pinhole for gas exchange. The analysis was carried out under nitrogen to prevent oxidation, with a purge gas flow of 50 \u0026micro;L/min. Samples were heated from 30\u0026deg;C to 300\u0026deg;C at 10\u0026deg;C/min, allowing observation of thermal events like glass transitions, melting points, and crystallization behaviors. After holding at 300\u0026deg;C for 5 minutes, they were cooled back to 30\u0026deg;C at the same rate to capture any reversible transitions. The degree of crystallinity and other thermal properties were determined based on the thermograms generated by applying the following equation [\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e].\u003cdiv id=\"Equ1\" class=\"Equation\"\u003e\u003cdiv format=\"TEX\" class=\"mathdisplay\" id=\"FileID_Equ1\" name=\"EquationSource\"\u003e\n$$\\:{X}_{C,DSC}=\\frac{\\varDelta\\:{H}_{f}-\\varDelta\\:{H}_{c}}{\\varDelta\\:{H}_{f}^{^\\circ\\:}}$$\u003c/div\u003e\u003cdiv class=\"EquationNumber\"\u003e1\u003c/div\u003e\u003c/div\u003e\u003c/p\u003e \u003cp\u003eWhere \u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:{X}_{C,DSC}\\)\u003c/span\u003e\u003c/span\u003e represents the degree of crystallinity, \u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:\\varDelta\\:{H}_{f}\\)\u003c/span\u003e\u003c/span\u003e the enthalpy of fusion or heat, \u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:\\varDelta\\:{H}_{c}\\)\u003c/span\u003e\u003c/span\u003e is the enthalpy of cold crystallization, signifies the heat of cold crystallization, both derived from the DSC thermograms. The standard enthalpy of fusion for fully crystalline PET is taken as 136 J\u0026middot;g\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003eassessed directly from DSC thermograms, and \u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:\\varDelta\\:{H}_{f}^{^\\circ\\:}\\)\u003c/span\u003e\u003c/span\u003e (136 J\u0026middot;g\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e) is the enthalpy of fusion of 100% crystalline PET[\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e].\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec10\" class=\"Section3\"\u003e \u003ch2\u003e2.6.2 Transmission Electron Microscope (TEM)\u003c/h2\u003e \u003cp\u003eThe size and morphology of nanoparticles were analyzed using HRTEM on a JEOL JEM 2100 microscope. This advanced tool features a single crystal LaB6 cathode and adjustable acceleration voltages of 80kV-200kV. With a magnification range of 1,200X to 1,000,000X, it enables atomic-scale imaging at 0.27 nm resolution.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec11\" class=\"Section3\"\u003e \u003ch2\u003e2.6.3 X-Ray Diffraction\u003c/h2\u003e \u003cp\u003eFor XRD analysis of nanoparticle powders, the Panalytical Empyrean 3, from Malvern, Netherlands, is utilized, capable of analyzing a wide range of sample types including powders and nanomaterials. Equipped with Cu-Kα radiation (1.54060\u0026Aring;) at 30mA and 40kV. The crystalline size of the nanoparticles will be calculated using the Scherrer formula[\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e],\u003cdiv id=\"Equ2\" class=\"Equation\"\u003e\u003cdiv format=\"TEX\" class=\"mathdisplay\" id=\"FileID_Equ2\" name=\"EquationSource\"\u003e\n$$\\:D=\\frac{k\\lambda\\:}{\\beta\\:\\text{c}\\text{o}\\text{s}\\theta\\:}$$\u003c/div\u003e\u003cdiv class=\"EquationNumber\"\u003e2\u003c/div\u003e\u003c/div\u003e\u003c/p\u003e \u003cp\u003eWhere k is a dimensionless shape factor, λ is the x-ray wavelength, β is the line broadening at half the maximum intensity (FWHM), and θ is the Bragg angle [\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e].\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec12\" class=\"Section3\"\u003e \u003ch2\u003e2.6.4 Field-Emission Scanning Electron Microscope (FE-SEM):\u003c/h2\u003e \u003cp\u003eField-Emission Scanning Electron Microscopy (FE-SEM) with the Zeiss SUPRA 55-VP was used for high-resolution imaging and precise measurement of polymer nanofibers and embedded nanoparticles. Nonconductive samples were sputter-coated with gold to enhance conductivity. This enabled accurate calculations of fiber diameters and nanoparticle distribution within the nanofibers.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec13\" class=\"Section3\"\u003e \u003ch2\u003e2.6.5 \u003cb\u003eMechanical Test\u003c/b\u003e:\u003c/h2\u003e \u003cp\u003eThe In Situ Tensile Stage is designed for mechanical testing within an SEM, allowing real-time observation of sample deformation. However, in our tests conducted outside the SEM, the fibers went out of focus as they deformed, Therefore, tensile tests were performed separately. Tensile samples were prepared according to the recommended dimensions (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e. a). Each fiber sample was tested three times to ensure accurate measurements. During testing, sample deformation was observed and the software generated force versus displacement graphs. These were converted into stress versus strain curves, incorporating the average thickness of the specimens, which was measured using a micrometer at five different locations per sample (\u003cb\u003eTable\u0026nbsp;1\u003c/b\u003e).\u003c/p\u003e \u003cp\u003e \u003cb\u003eTable\u0026nbsp;1. Thickness measurement of tensile samples\u003c/b\u003e \u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"No\" id=\"Taba\" border=\"1\"\u003e \u003ccolgroup cols=\"2\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\"\u0026plusmn;\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSample\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eThickness mm\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eP10\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e0.022\u0026thinsp;\u0026plusmn;\u0026thinsp;0.0003\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eP15\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e0.036\u0026thinsp;\u0026plusmn;\u0026thinsp;0.004\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eP20\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e0.029\u0026thinsp;\u0026plusmn;\u0026thinsp;0.002\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eP15F\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e0.039\u0026thinsp;\u0026plusmn;\u0026thinsp;0.001\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003eTo compare the mechanical behavior of PET bottle materials before and after electrospinning, tensile strength and deformation were measured using a Zwick/Roell Z100 universal testing machine. Three samples were cut from the straight part of the PET water bottle, each with a thickness of 0.2 mm and a width of 3.9 mm (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e.b).\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec14\" class=\"Section3\"\u003e \u003ch2\u003e2.6.6 Membrane Adsorption Efficiency Tests:\u003c/h2\u003e \u003cp\u003eTo evaluate the copper ion removal efficiency of microfiber membranes, both with and without nanoparticles, experiments were conducted using a 1 mM CuSO\u003csub\u003e4\u003c/sub\u003e solution as the contaminant model. For this, 249.68 mg of copper sulfate pentahydrate was dissolved in deionized water to make 1 liter of solution, which was stirred for 3 hours to ensure uniform copper ion concentration. Microfiber membranes, sized 5x5 cm\u003csup\u003e2\u003c/sup\u003e and weighing 150\u0026ndash;200 mg, were submerged in 100 mL of this solution for 120 minutes at room temperature. The quantification (q, in mg/g) of the membranes' adsorption capacity was achieved through the formula:\u003cdiv id=\"Equ3\" class=\"Equation\"\u003e\u003cdiv format=\"TEX\" class=\"mathdisplay\" id=\"FileID_Equ3\" name=\"EquationSource\"\u003e\n$$\\:q=\\frac{{(C}_{o}-{C}_{e})\\times\\:V}{{M}_{abs}}$$\u003c/div\u003e\u003cdiv class=\"EquationNumber\"\u003e3\u003c/div\u003e\u003c/div\u003e\u003c/p\u003e \u003cp\u003eWhere \u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:{C}_{o}\\)\u003c/span\u003e\u003c/span\u003e​ and \u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:{C}_{e}\\)\u003c/span\u003e\u003c/span\u003e​ represent the initial and equilibrium concentrations of copper ions in mg L\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e, V denotes the volume of the solution in liters, and \u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:{M}_{abs}\\)\u003c/span\u003e\u003c/span\u003e is the mass of the adsorbing microfiber membrane in grams. This formula facilitated a direct comparison between the copper ion adsorption capacities of the pure and nanoparticle-incorporated microfiber membranes. All samples where tested further tested using an ICP test from Cu ions detection after filtration.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec15\" class=\"Section3\"\u003e \u003ch2\u003e2.6.7 Inductively Coupled Plasma- Optical Emission Spectroscopy (ICP- OES):\u003c/h2\u003e \u003cp\u003eMetal ion concentrations are analyzed by first digesting samples in an acid solution using the Anton-Paar Multiwave PRO microwave digestion system [\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e]. The digested samples are then measured with the Agilent 5100 ICP-OES [\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e]. Calibration curves, including a blank and at least three standards, are created for each measurement series. The accuracy of the results is verified with external reference standards and quality control samples from NIST. This process follows the 2023 APHA guidelines for water quality analysis, ensuring compliance with best practices.\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e"},{"header":"3 Results","content":"\u003cdiv id=\"Sec17\" class=\"Section2\"\u003e \u003ch2\u003e3.1 Electrospinning\u003c/h2\u003e \u003cp\u003eThe static vertical electrospinning setup produced unevenly distributed nanofibers, demonstrating dense areas and inconsistencies due to its stationary collector. In contrast, the rotating horizontal setup, with its dynamic drum collector, achieved uniform fiber distribution across the collector surface, significantly reducing density variations and improving control over mat characteristics like thickness and porosity. Figure\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003ea and Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003eb contrasts the outcomes of two electrospinning methods. The heat treatment at 80\u0026deg;C resulted in noticeable darkening of PET nanofiber films, indicating significant magnetite nanoparticle migration to the surface. This transformation highlights nanoparticle movement in response to thermal exposure below the polymer\u0026rsquo;s glass transition temperature, revealing interactions between polymer and nanoparticle dynamics. Figure\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e.c and Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e.d illustrates the before and after images of PET/Fe\u003csub\u003e3\u003c/sub\u003eO\u003csub\u003e4\u003c/sub\u003e films.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec18\" class=\"Section2\"\u003e \u003ch2\u003e3.2 Analysis Techniques\u003c/h2\u003e \u003cdiv id=\"Sec19\" class=\"Section3\"\u003e \u003ch2\u003e3.2.1 Differential scanning calorimetry (DSC):\u003c/h2\u003e \u003cp\u003eThe Differential scanning calorimetry (DSC) of PET and its nanofiber shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e. The calculated crystallinity index (X\u003csub\u003ec\u003c/sub\u003e) for the PET bottle was 1.169%, with the P10, P15, and P20 nanofibers crystallinity of 2.118%, 0.985%, and 4.971% respectively, Table\u0026nbsp;2. The melting temperatures (T\u003csub\u003em\u003c/sub\u003e) across all samples showed minimal variation. The DSC thermograms for PET and its nanocomposites exhibit distinctive double peaks, suggesting complex crystalline structures and morphologies.\u003c/p\u003e \u003cp\u003e \u003cb\u003eTable\u0026nbsp;2. Crystallinity of PET bottle and different polymer concentration samples\u003c/b\u003e \u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"No\" id=\"Tabb\" border=\"1\"\u003e \u003ccolgroup cols=\"5\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eH\u003csub\u003ef\u003c/sub\u003e J/g\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eH\u003csub\u003ec\u003c/sub\u003e J/g\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eX\u003csub\u003ec,DSC\u003c/sub\u003e (%)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eT\u003csub\u003em\u003c/sub\u003e (\u0026deg;C)\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePET\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e39.35\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e37.76\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e1.169\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e248.79\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eP10\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e39.35\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e36.47\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e2.118\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e247.12\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eP15\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e35.16\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e36.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.985\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e246.44\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eP20\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e30.56\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e37.32\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e4.971\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e246.60\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec20\" class=\"Section3\"\u003e \u003ch2\u003e3.2.2 Transmission Electron Microscope (TEM)\u003c/h2\u003e \u003cp\u003eThe magnetite nanoparticles exhibit a polydisperse size distribution, with diameters ranging from approximately 12 nm to over 30 nm. TEM images (Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e) reveal significant aggregation, with particles forming clusters of varying sizes. The nanoparticle shapes vary from spherical to irregular, with a relatively smooth surface morphology despite the observed clustering.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec21\" class=\"Section3\"\u003e \u003ch2\u003e3.2.3 X-Ray Diffraction\u003c/h2\u003e \u003cp\u003eThe X-ray diffraction (XRD) analysis, shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e6\u003c/span\u003e, identified synthesized iron oxide nanoparticles as magnetite (Fe\u003csub\u003e3\u003c/sub\u003eO\u003csub\u003e4\u003c/sub\u003e) using card No. 01-084-2782. Key peaks include 2θ\u0026thinsp;=\u0026thinsp;35.5452\u0026deg; (d-spacing 2.52359 \u0026Aring;) for the (311) plane and 2θ\u0026thinsp;=\u0026thinsp;62.8686\u0026deg; (d-spacing 1.47703 \u0026Aring;) for the (440) plane, with calculated crystal sizes of approximately 17 nm. Other notable peaks were observed at 2θ\u0026thinsp;=\u0026thinsp;18.3847\u0026deg; and 30.2662\u0026deg; for the (111) and (220) planes, respectively. The average crystallite size was estimated at 19.7\u0026thinsp;\u0026plusmn;\u0026thinsp;8.13 nm, aligning with TEM results.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec22\" class=\"Section3\"\u003e \u003ch2\u003e3.2.4 Field-Emission Scanning Electron Microscope (FE-SEM):\u003c/h2\u003e \u003cp\u003eThe microstructural analysis of PET films reveals key findings related to fiber concentration and its impact on fiber diameter and orientation, which are critical for mechanical and filtration properties. At 10 wt% concentration (Fig.\u0026nbsp;\u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e7\u003c/span\u003e.a), the tightly packed fibers have an average diameter of (0.42\u0026thinsp;\u0026plusmn;\u0026thinsp;0.03) \u0026micro;m with minimal angular deviation. Figure\u0026nbsp;\u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e7\u003c/span\u003e.b illustrates this compact structure. At 15 wt.% concentration, fibers have an average diameter of (1.06\u0026thinsp;\u0026plusmn;\u0026thinsp;0.08) \u0026micro;m with increased angular deviation, resulting in a more diverse orientation (Fig.\u0026nbsp;\u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e7\u003c/span\u003e.c). At 20 wt.%, the diameter increases to (1.56\u0026thinsp;\u0026plusmn;\u0026thinsp;0.28) \u0026micro;m, with broader angular deviation (Fig.\u0026nbsp;\u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e7\u003c/span\u003e.d).\u003c/p\u003e \u003cp\u003eThe FE-SEM analysis of P15F films, before and after heat treatment, revealed key morphological changes. Before treatment (Fig.\u0026nbsp;\u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e7\u003c/span\u003e.\u003cb\u003ee\u003c/b\u003e), the PET/Fe\u003csub\u003e3\u003c/sub\u003eO\u003csub\u003e4\u003c/sub\u003e film exhibited a smooth surface with well-dispersed nanoparticles (Fig.\u0026nbsp;\u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e7\u003c/span\u003e.\u003cb\u003ef\u003c/b\u003e). Post-treatment at 80\u0026deg;C (Fig.\u0026nbsp;\u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e7\u003c/span\u003e.\u003cb\u003eg\u003c/b\u003e), significant nanoparticle migration towards the surface was observed, leading to rougher textures and heterogeneous nanoparticle distribution. Higher magnification images (Fig.\u0026nbsp;\u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e7\u003c/span\u003e.\u003cb\u003eh\u003c/b\u003e) confirmed increased nanoparticle visibility and surface density post-heat treatment, without compromising the fibers' structural integrity.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec23\" class=\"Section3\"\u003e \u003ch2\u003e3.2.5 Mechanical Test:\u003c/h2\u003e \u003cp\u003eThe mechanical properties of PET bottles, as shown in Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e3\u003c/span\u003e. PET microfibers produced at different concentrations (P10, P15, P20) exhibit varying mechanical properties. P10 fibers show a UTS of 66\u0026thinsp;\u0026plusmn;\u0026thinsp;5 MPa, P15 fibers 47\u0026thinsp;\u0026plusmn;\u0026thinsp;2 MPa, and P20 fibers 31\u0026thinsp;\u0026plusmn;\u0026thinsp;1 MPa. While P15 fibers show a moderate mechanical integrity and a significant elongation at break of 162\u0026thinsp;\u0026plusmn;\u0026thinsp;7%, the introduction of Fe\u003csub\u003e3\u003c/sub\u003eO\u003csub\u003e4\u003c/sub\u003e nanoparticles in P15F results in a UTS of 86\u0026thinsp;\u0026plusmn;\u0026thinsp;10 MPa, with a reduction in elongation to 31\u0026thinsp;\u0026plusmn;\u0026thinsp;5% and toughness to 28\u0026thinsp;\u0026plusmn;\u0026thinsp;5 MJ/m\u0026sup3;. Figure\u0026nbsp;\u003cspan refid=\"Fig7\" class=\"InternalRef\"\u003e8\u003c/span\u003e shows the Stress vs. Strain curves for PET bottles and nanofibers at different concentrations.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 3\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eMechanical Properties of the PET bottle and nanofibers\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"6\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\"\u0026plusmn;\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\"\u0026plusmn;\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\"\u0026plusmn;\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\"\u0026plusmn;\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\"\u0026plusmn;\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eP10\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eP15\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eP20\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eP15F\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c6\"\u003e \u003cp\u003ePET Bottle\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eUTS (MPa)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e66\u0026thinsp;\u0026plusmn;\u0026thinsp;5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e47\u0026thinsp;\u0026plusmn;\u0026thinsp;2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c4\"\u003e \u003cp\u003e31\u0026thinsp;\u0026plusmn;\u0026thinsp;1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c5\"\u003e \u003cp\u003e86\u0026thinsp;\u0026plusmn;\u0026thinsp;10\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c6\"\u003e \u003cp\u003e121\u0026thinsp;\u0026plusmn;\u0026thinsp;10\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eEl%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e58\u0026thinsp;\u0026plusmn;\u0026thinsp;12\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e162\u0026thinsp;\u0026plusmn;\u0026thinsp;7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c4\"\u003e \u003cp\u003e54\u0026thinsp;\u0026plusmn;\u0026thinsp;7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c5\"\u003e \u003cp\u003e31 \u0026plusmn; 5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c6\"\u003e \u003cp\u003e34.8\u0026thinsp;\u0026plusmn;\u0026thinsp;3.3\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eElastic Modules (GPa)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e0.75\u0026thinsp;\u0026plusmn;\u0026thinsp;0.22\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e0.68\u0026thinsp;\u0026plusmn;\u0026thinsp;1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c4\"\u003e \u003cp\u003e0.37\u0026thinsp;\u0026plusmn;\u0026thinsp;0.19\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c5\"\u003e \u003cp\u003e1\u0026thinsp;\u0026plusmn;\u0026thinsp;0.14\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c6\"\u003e \u003cp\u003e3684\u0026thinsp;\u0026plusmn;\u0026thinsp;95\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eToughness MJ/m3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e34\u0026thinsp;\u0026plusmn;\u0026thinsp;8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e63\u0026thinsp;\u0026plusmn;\u0026thinsp;1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c4\"\u003e \u003cp\u003e13\u0026thinsp;\u0026plusmn;\u0026thinsp;2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c5\"\u003e \u003cp\u003e28\u0026thinsp;\u0026plusmn;\u0026thinsp;5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c6\"\u003e \u003cp\u003e24.6\u0026thinsp;\u0026plusmn;\u0026thinsp;11\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec24\" class=\"Section3\"\u003e \u003ch2\u003e3.2.6 Membrane Adsorption Efficiency Tests:\u003c/h2\u003e \u003cp\u003eTable\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e4\u003c/span\u003e shows the adsorption test results for PET fibers with 1mM Cu\u0026sup2;⁺ ions. The lower concentration PET fibers exhibit an adsorption capacity of 12 mg/g. P15 fibers show a slightly lower adsorption capacity of 11.1 mg/g, while P20 fibers have a further reduced capacity of 6 mg/g. The addition of Fe\u003csub\u003e3\u003c/sub\u003eO\u003csub\u003e4\u003c/sub\u003e nanoparticles to P15 significantly enhances adsorption capacity to 19.9 mg/g. Fe\u003csub\u003e3\u003c/sub\u003eO\u003csub\u003e4\u003c/sub\u003e improves adsorption in P20 fibers, but not as effectively as in P15F.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab2\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 4\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eAdsorption Test Results on all PET Samples with Co of 1mM Cu\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"4\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSample\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eQ Adsorption Capacity mg/cm\u003csup\u003e2\u003c/sup\u003e\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eQ Adsorption Capacity mmol/g\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eQ Adsorption Capacity mg/g\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eP10\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e0.09\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e0.19\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e12\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eP15\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e0.06\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e0.17\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e11.1\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eP20\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e0.05\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e0.09\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e6\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eP15F\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e0.11\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e0.31\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e19.9\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eP20F\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e0.08\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e0.2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e12.8\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003c/div\u003e \u003c/div\u003e"},{"header":"4 Discussion","content":"\u003cp\u003eIn the discussion of PET nanofibers synthesized through various electrospinning setups, post-electrospinning treatments, and characterization techniques, the focus is on optimizing fiber properties for water filtration applications. This section investigates how the electrospinning process, nanoparticle integration, and thermal treatments influence nanofiber morphology and functionality, with the aim of enhancing environmental remediation efforts.\u003c/p\u003e \u003cp\u003eThe static vertical electrospinning setup produces nanofibers with a non-uniform distribution, as dense fiber accumulation occurs due to the absence of dynamic substrate movement. This can be problematic for filtration applications that require uniform fiber distribution to ensure consistent pore sizes throughout the material. In contrast, the rotating horizontal electrospinning process, which uses a dynamic drum collector, achieves more uniform nanofiber distribution due to the drum's continuous motion, allowing for layer-by-layer deposition and minimal fiber accumulation (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e.b). This uniformity is crucial for applications where consistent fiber distribution is paramount.\u003c/p\u003e \u003cp\u003ePost-electrospinning heat treatment reveals significant insights into nanoparticle behavior within the polymer matrix. The observed migration of magnetite nanoparticles to the surface of PET nanofibers during heat treatment below the T\u003csub\u003eg\u003c/sub\u003e at 80 C\u0026deg; challenges conventional understanding of polymer dynamics. Even below the T\u003csub\u003eg\u003c/sub\u003e, polymers exhibit sufficient segmental mobility to allow for nanoparticle migration, suggesting that traditional views on polymer behavior at the nanoscale need adjustment [\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e]. This enhanced surface roughness and altered nanoparticle distribution increase the functional surface area, potentially improving the adsorption properties of the fibers for filtration applications.\u003c/p\u003e \u003cp\u003eDifferential Scanning Calorimetry (DSC) analyses the thermal properties of the nanofibers. DSC showed no significant variations across different polymer concentrations in thermal transitions related to the crystallinity index (X\u003csub\u003ec\u003c/sub\u003e) of the nanofibers, indicating that polymer concentration does not substantially affect melting temperatures (T\u003csub\u003em\u003c/sub\u003e). However, The DSC thermograms for PET nanofibers exhibit distinctive double peaks, suggesting complex crystalline structures and morphologies (Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e). This phenomenon is likely due to the high surface-to-volume ratio in nanofibers and the rapid cooling during electrospinning, which induces non-equilibrium states and varied lamellar thicknesses. Such behavior aligns with theories on dual morphology and recrystallization-remelt mechanisms, which explain the diverse melting behaviors observed in nanofibers compared to bulk materials. This is consistent with the literature, as multiple melting behaviors in PET, influenced by factors like lamellar thickening and reorganization during heating, have been previously reported by Kong and Hay and Woo and Ko [\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e], [\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eTEM analysis revealed a polydisperse size distribution for Fe\u003csub\u003e3\u003c/sub\u003eO\u003csub\u003e4\u003c/sub\u003e nanoparticles, with particle sizes ranging from approximately 12 nm to over 30 nm. The nanoparticles showed a tendency to aggregate, forming clusters. These aggregates may reduce the effective surface area available for adsorption in filtration membranes. XRD analysis confirmed the crystallographic structure of the synthesized Fe\u003csub\u003e3\u003c/sub\u003eO\u003csub\u003e4\u003c/sub\u003e nanoparticles, with distinct peaks corresponding to the magnetite phase. The average crystal size was around 17 nm, aligning with the TEM results. The uniformity of particle size and structure suggests a consistent synthesis process.\u003c/p\u003e \u003cp\u003eField-Emission Scanning Electron Microscopy (FE-SEM) studies the modifications in PET nanofibers due to varied polymer concentrations and thermal processing. Increasing the polymer content from 10 wt% to 20 wt% leads to an increase in fiber thickness, transitioning from a dense, finely structured arrangement to a looser configuration with thicker fibers. This structural modification significantly improves the mats' permeability by enlarging the inter-fiber pore spaces, potentially enhancing filtration efficiency but possibly reducing the fibers' mechanical strength. Additionally, heat treatments conducted below the glass transition temperature, promote the migration of magnetite nanoparticles towards the surfaces of the fibers. This alteration not only roughens the fiber surfaces but also differentiates the nanoparticle distribution across them, thus enhancing their properties for adsorption and catalytic activity. Such enhancements are crucial for the effective deployment of nanofibers in advanced purification systems, where optimal surface properties are critical for interacting with and removing contaminants.\u003c/p\u003e \u003cp\u003eThe mechanical properties of PET nanofibers varied significantly with polymer concentration. At 10 wt%, PET nanofibers exhibited high tensile strength (UTS of 66\u0026thinsp;\u0026plusmn;\u0026thinsp;5 MPa) and moderate ductility, making them suitable for high-pressure filtration applications. At 15 wt%, the nanofibers demonstrated increased ductility and toughness, which could be advantageous for filtration applications requiring materials that withstand dynamic stresses. When comparing our PET nanofibers to those reported in the literature for recycled PET [\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e], several notable differences emerge. Our P10 fibers, outperform the reference's 1.0 \u0026micro;m fibers, highlighting the efficacy of our production method at this concentration. Although our P15 fibers exhibit a lower UTS of 47\u0026thinsp;\u0026plusmn;\u0026thinsp;2 MPa compared to the 62.5 MPa reported for similar fibers, they show a significantly higher elongation at break of 162\u0026thinsp;\u0026plusmn;\u0026thinsp;7%. This indicates that our P15 fibers offer greater flexibility, a crucial characteristic for filtration applications where materials must adapt to various stresses. The addition of F\u003csub\u003ee\u003c/sub\u003e3O\u003csub\u003e4\u003c/sub\u003e nanoparticles in the P15F samples further enhanced tensile strength (UTS of 86\u0026thinsp;\u0026plusmn;\u0026thinsp;10 MPa) but reduced ductility and toughness, highlighting a trade-off between strength and flexibility. This trade-off is a recognized phenomenon in composite materials, where increased filler content can enhance yield strength at the cost of ductility and energy adsorption capacity, as described in previous studies[\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e]\u003c/p\u003e \u003cp\u003eThe adsorption efficiency of PET nanofibers was tested using a 1mM Cu\u0026sup2;⁺ solution. At lower polymer concentrations (P10), the nanofibers demonstrated a high adsorption capacity (0.19 mmol/g), likely due to the increased surface area available for adsorption. As fiber diameter increased in the P15 and P20 samples, adsorption capacity decreased slightly due to the reduction in surface-to-volume ratio. Compared to a previous study where they reached a Cu (II) adsorption capacity of 0.06 mmol/g for similar PET electrospun nanofiber membrane[\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e]. However, the incorporation of Fe\u003csub\u003e3\u003c/sub\u003eO\u003csub\u003e4\u003c/sub\u003e nanoparticles significantly enhanced adsorption capacity in the P15F samples (0.31 mmol/g), indicating that the magnetic properties of Fe\u003csub\u003e3\u003c/sub\u003eO\u003csub\u003e4\u003c/sub\u003e improve the material's ability to remove heavy metals from water. In previous study, they reached an adsorption capacity of Fe\u003csub\u003e3\u003c/sub\u003eO\u003csub\u003e4\u003c/sub\u003e for Cu(II) 0.160 mmol g\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e [\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e], making the current findings superior for both PET nanofibers and nanocomposites, compared to previously reported results.\u003c/p\u003e"},{"header":"5 Conclusion","content":"\u003cp\u003eThis research represents a step forward in water purification technologies by repurposing recycled Polyethylene Terephthalate (PET) bottles into advanced purification membranes. These membranes are enhanced through the incorporation of metal nanoparticles, particularly Iron Oxide (Fe\u003csub\u003e3\u003c/sub\u003eO\u003csub\u003e4\u003c/sub\u003e), to significantly enhance their water treatment capabilities. Optimized electrospinning produced uniform PET nanofibers, critical for efficient filtration. Incorporating Fe\u003csub\u003e3\u003c/sub\u003eO\u003csub\u003e4\u003c/sub\u003e ensured stable and evenly distributed nanoparticles, with heat treatments promoting their migration to the fiber surface, providing valuable insights for tailoring nanocomposites.\u003c/p\u003e \u003cp\u003eCharacterization techniques, including TEM, XRD, and FE-SEM, confirmed the nanofibers' structural and morphological attributes, with Fe\u003csub\u003e3\u003c/sub\u003eO\u003csub\u003e4\u003c/sub\u003e nanoparticles exhibiting a size range of 12\u0026ndash;30 nm. Thermal and mechanical testing showed that fibers with 10 wt.% polymer concentration achieved the highest tensile strength (66 MPa), while 15 wt.% concentration improved ductility (162%). Adding Fe\u003csub\u003e3\u003c/sub\u003eO\u003csub\u003e4\u003c/sub\u003e nanoparticles boosted tensile strength to 86 MPa, though with reduced flexibility, demonstrating the balance required in nanoparticle-enhanced fibers. Adsorption tests revealed that Fe₃O₄-infused PET membranes significantly improved contaminant removal, achieving a capacity of 19.8 mg/g, attributed to the nanoparticles' high surface energy and affinity for heavy metals.\u003c/p\u003e \u003cp\u003eFuture research should investigate the use of advanced nanoparticles like TiO₂, Ag, ZnO, and graphene oxide for their superior adsorptive and antibacterial properties. Exploring innovative electrospinning techniques and post-treatment processes can further enhance membrane performance. Field testing and environmental impact assessments are crucial to ensure these technologies are scalable, sustainable, and effective for real-world water purification applications.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cul\u003e\n \u003cli\u003e\u003cstrong\u003eEthics, Consent to Participate, and Consent to Publish Declarations:\u003c/strong\u003e Not applicable.\u003c/li\u003e\n \u003cli\u003e\u003cstrong\u003eClinical Trial Registration Details:\u003c/strong\u003e Not applicable.\u003c/li\u003e\n \u003cli\u003e\u003cstrong\u003eFunding:\u003c/strong\u003e No funding was received for conducting this study.\u003c/li\u003e\n \u003cli\u003e\u003cstrong\u003eCompeting Interests:\u003c/strong\u003e The authors declare that they have no competing financial or non-financial interests.\u003c/li\u003e\n \u003cli\u003e\u003cstrong\u003eAuthor Contributions:\u003c/strong\u003e All authors contributed to the conception and design. Material preparation, data collection, and analysis were performed by Amira Hassan. The manuscript draft was prepared by Amira Hassan and critically revised by all authors. All authors read and approved the final manuscript.\u003c/li\u003e\n \u003cli\u003e\u003cstrong\u003eCompliance with Ethical Standards:\u003c/strong\u003e This article does not contain any studies involving human or animal subjects.\u003c/li\u003e\n \u003cli\u003e\u003cstrong\u003eData Availability Statement:\u003c/strong\u003e The datasets generated during and/or analyzed during the current study are available from the corresponding author upon reasonable request.\u003c/li\u003e\n\u003c/ul\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eAli EM, El-Shehawy AS (2023) Metallic Nanoparticles and Bioremediation for Wastewater Treatment. In: Shah MP (ed) Advanced Application of Nanotechnology to Industrial Wastewater. Springer Nature Singapore, Singapore, pp 215\u0026ndash;239. https://doi.org/10.1007/978-981-99-3292-4_11\u003c/li\u003e\n\u003cli\u003eMishra S, Chowdhary P, Bharagava RN (2019) Conventional Methods for the Removal of Industrial Pollutants, Their Merits and Demerits. In: Bharagava RN, Chowdhary P (eds) Emerging and Eco-Friendly Approaches for Waste Management. Springer Singapore, Singapore, pp 1\u0026ndash;31. https://doi.org/10.1007/978-981-10-8669-4_1\u003c/li\u003e\n\u003cli\u003eRath ME, Choi SY, Sayoc J, Shin J, Hong SG, Park JY (2019) Validation of Nanoparticle Tracking Analysis in Characterizing Extracellular Vesicle Isolated from Polydisperse Biological Samples. FASEB J 33(lb599). https://doi.org/10.1096/fasebj.2019.33.1_supplement.lb599\u003c/li\u003e\n\u003cli\u003eJi K, et al (2023) Research Progress of Water Treatment Technology Based on Nanofiber Membranes. Polymers 15(3). https://doi.org/10.3390/polym15030741\u003c/li\u003e\n\u003cli\u003eSalunkhe HJ, et al (2020) Role of Nanotechnology to Control Water Pollution. International Journal of Researches in Biosciences, Agriculture and Technology. Available: www.ijrbat.in\u003c/li\u003e\n\u003cli\u003eMariana M, et al (2022) Recent trends and future prospects of nanostructured aerogels in water treatment applications. J Water Process Eng 45:102481. https://doi.org/10.1016/J.JWPE.2021.102481\u003c/li\u003e\n\u003cli\u003eZhang Y, Wang F, Wang Y (2021) Recent developments of electrospun nanofibrous materials as novel adsorbents for water treatment. Mater Today Commun 27:102272. https://doi.org/10.1016/J.MTCOMM.2021.102272\u003c/li\u003e\n\u003cli\u003eGee S, Johnson B, Smith AL (2018) Optimizing electrospinning parameters for piezoelectric PVDF nanofiber membranes. J Memb Sci 563:804\u0026ndash;812. https://doi.org/10.1016/j.memsci.2018.06.050\u003c/li\u003e\n\u003cli\u003eT. M. S. et al (2021) A review of recent progress in polymeric electrospun nanofiber membranes in addressing safe water global issues. RSC Adv 11(16):9638\u0026ndash;9663. https://doi.org/10.1039/D1RA00060H\u003c/li\u003e\n\u003cli\u003eJannah NR, Onggo D (2019) Synthesis of Fe\u003csub\u003e3\u003c/sub\u003eO\u003csub\u003e4 \u003c/sub\u003enanoparticles for colour removal of printing ink solution. J Phys Conf Ser 1245. https://doi.org/10.1088/1742-6596/1245/1/012040\u003c/li\u003e\n\u003cli\u003eHossain MT, Shahid MA, Ali A (2022) Development of nanofibrous membrane from recycled polyethene terephthalate bottle by electrospinning. OpenNano 8:100089. https://doi.org/10.1016/j.onano.2022.100089\u003c/li\u003e\n\u003cli\u003eSichina WJ (2000) DSC as Problem Solving Tool: Measurement of Percent Crystallinity of Thermoplastics. Available: www.perkinelmer.com\u003c/li\u003e\n\u003cli\u003eStrain IN, Wu Q, Pourrahimi AM, Hedenqvist MS, Olsson RT, Andersson RL (2015) Electrospinning of recycled PET to generate tough mesomorphic fibre membranes for smoke filtration. J Mater Chem A Mater 3(4):1632\u0026ndash;1640. https://doi.org/10.1039/c4ta06191h\u003c/li\u003e\n\u003cli\u003eHossain MT, Hossain MM, Begum MHA, Shahjahan M, Islam MM, Saha B (2018) Magnetite (Fe\u003csub\u003e3\u003c/sub\u003eO\u003csub\u003e4\u003c/sub\u003e) nanoparticles for chromium removal. Bangladesh J Sci Ind Res 53(3):219\u0026ndash;224. https://doi.org/10.3329/bjsir.v53i3.38269\u003c/li\u003e\n\u003cli\u003eAnton Paar Multiwave 5000. https://www.anton-paar.com/se-en/products/details/multiwave-5000/\u003c/li\u003e\n\u003cli\u003eAgilent 5100 ICP-OES Technical Overview. What is Synchronous Vertical Dual View (SVDV). www.agilent.com\u003c/li\u003e\n\u003cli\u003eQu T, et al (2023) Structure\u0026ndash;Property Relationship, Glass Transition, and Crystallization Behaviors of Conjugated Polymers. Polymers 15(21):4268. https://doi.org/10.3390/polym15214268\u003c/li\u003e\n\u003cli\u003eKong Y, Hay JN Multiple melting behaviour of poly(ethylene terephthalate). Available: www.elsevier.com/locate/polymer\u003c/li\u003e\n\u003cli\u003eWoo EM, Ko TY (1996) A differential scanning calorimetry study on poly(ethylene terephthalate) isothermally crystallized at stepwise temperatures: multiple melting behavior re-investigated. Colloid Polym Sci 274. https://doi.org/10.1007/BF00652396\u003c/li\u003e\n\u003cli\u003eMatthews FL, Rawlings RD (1999) Reinforcements and the reinforcement\u0026ndash;matrix interface. In: Composite Materials. pp 29\u0026ndash;77. https://doi.org/10.1016/B978-1-85573-473-9.50005-9\u003c/li\u003e\n\u003cli\u003eTotito TC, Laatikainen K, Pereao O, Bode-Aluko C, Petrik L (2021) Adsorptive Recovery of Cu2+ from Aqueous Solution by Polyethylene Terephthalate Nanofibres Modified with 2-(Aminomethyl)Pyridine. Appl Sci 11(24):11912. https://doi.org/10.3390/app112411912\u003c/li\u003e\n\u003cli\u003eGiraldo L, Erto A, Moreno-Piraj\u0026aacute;n JC (2013) Magnetite nanoparticles for removal of heavy metals from aqueous solutions: synthesis and characterization. Adsorption 19(2):465\u0026ndash;474. https://doi.org/10.1007/s10450-012-9468-1\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":"discover-materials","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"dime","sideBox":"Learn more about [Discover Materials](https://www.springer.com/journal/43939)","snPcode":"","submissionUrl":"","title":"Discover Materials","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Discover Series","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"Nanocomposites, Nanoparticles, Magnetic Nanoparticles, Iron Oxide, Electrospinning, Recycled Materials, Metal Ions Removal, Wastewater Treatment","lastPublishedDoi":"10.21203/rs.3.rs-6745323/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-6745323/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eThis study investigates the development and performance of polyethylene terephthalate (PET) nanofiber, made from recycled PET bottles, for water purification applications. The research focuses on incorporating Iron Oxide (Fe\u003csub\u003e3\u003c/sub\u003eO\u003csub\u003e4\u003c/sub\u003e) nanoparticles into this membrane, optimizing their performance for heavy metal ion removal. By refining the electrospinning process, the study successfully produced uniform nanofibers with enhanced filtration capabilities. A significant difference in the fibers' properties was observed by varying polymer concentrations in electrospinning solution. Nanofibers produced at a 10 wt.% concentration exhibited the highest tensile strength of 66 MPa and balanced flexibility, making them suitable for high-pressure filtration scenarios. The fibers at 15 wt.% demonstrated remarkable ductility with an elongation at break of 162%, ideal for dynamic filtration systems. The introduction of Iron Oxide (Fe\u003csub\u003e3\u003c/sub\u003eO\u003csub\u003e4\u003c/sub\u003e) nanoparticles significantly increased the Ultimate Tensile Strength to 86 MPa. Adsorption tests revealed that the 10 wt.% fibers had the highest capacity for copper ion removal at 12 mg/g, attributed to their smaller fiber diameter and larger surface area. The addition of Fe\u003csub\u003e3\u003c/sub\u003eO\u003csub\u003e4\u003c/sub\u003e nanoparticles further improved the adsorption capacity, reaching 19.8 mg/g for heavy metal ions. This enhancement is attributed to the high surface energy and strong affinity of Fe\u003csub\u003e3\u003c/sub\u003eO\u003csub\u003e4\u003c/sub\u003e for contaminants. These findings underscore the potential of PET nanocomposites in providing efficient and sustainable water purification solutions, with performance tailored by adjusting polymer concentrations and nanoparticles integrations.\u003c/p\u003e","manuscriptTitle":"Fabrication and Characterization of Nano-loaded Recycled Materials for Water Purification, Part I: Iron Oxide Nanoparticles Incorporation","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-06-10 11:24:34","doi":"10.21203/rs.3.rs-6745323/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2025-06-17T09:10:33+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-06-15T10:13:59+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-06-14T12:05:24+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"85708979439268668373630866847796975898","date":"2025-06-13T11:28:20+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"303799841976758878988546431960452889783","date":"2025-06-06T16:28:22+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2025-06-06T11:05:14+00:00","index":"","fulltext":""},{"type":"editorInvited","content":"","date":"2025-06-02T13:11:27+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2025-05-29T01:13:10+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2025-05-29T01:09:42+00:00","index":"","fulltext":""},{"type":"submitted","content":"Discover Materials","date":"2025-05-25T18:43:28+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"discover-materials","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"dime","sideBox":"Learn more about [Discover Materials](https://www.springer.com/journal/43939)","snPcode":"","submissionUrl":"","title":"Discover Materials","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Discover Series","inReviewEnabled":true,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"2d00dfef-1673-4cbb-877f-7d7c5ae888fd","owner":[],"postedDate":"June 10th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[],"tags":[],"updatedAt":"2025-08-11T16:08:30+00:00","versionOfRecord":{"articleIdentity":"rs-6745323","link":"https://doi.org/10.1007/s43939-025-00343-2","journal":{"identity":"discover-materials","isVorOnly":false,"title":"Discover Materials"},"publishedOn":"2025-08-05 15:58:08","publishedOnDateReadable":"August 5th, 2025"},"versionCreatedAt":"2025-06-10 11:24:34","video":"","vorDoi":"10.1007/s43939-025-00343-2","vorDoiUrl":"https://doi.org/10.1007/s43939-025-00343-2","workflowStages":[]},"version":"v1","identity":"rs-6745323","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-6745323","identity":"rs-6745323","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}