Search Results (217)

Electrospun nanofiber membranes based on cellulose acetate (CA) have gained increasing attention for wastewater treatment due to their high surface area, tuneable structure, and ease of functionalization. In this study, the performance of CA membranes was enhanced by incorporating aluminum oxide (Al₂O₃) nanoparticles (NPs) at varying concentrations (0–2 wt.%). The structural, morphological, and thermal properties of the resulting CA/Al₂O₃ nanocomposite membranes were investigated through FTIR, XRD, SEM, water contact angle (WCA), pore size measurements, and DSC analyses. FTIR and XRD confirmed strong interactions and the uniform dispersion of the Al₂O₃ NPs within the CA matrix. The incorporation of Al₂O₃ improved membrane hydrophilicity, reducing the WCA from 107° to 35°, and increased the average pore size from 0.62 µm to 0.86 µm. These modifications led to enhanced filtration performance, with the membrane containing 2 wt.% Al₂O₃ achieving a 99% removal efficiency for Indigo Carmine (IC) dye, a maximum adsorption capacity of 45.59 mg/g, and a high permeate flux of 175.47 L·m⁻² h⁻¹ bar⁻¹. Additionally, phytotoxicity tests using Lactuca sativa seeds showed a significant increase in germination index from 20% (untreated) to 88% (treated), confirming the safety of the permeate for potential reuse in agricultural irrigation. These results highlight the effectiveness of Al₂O₃-modified CA electrospun membranes for sustainable wastewater treatment and water reuse. Full article

Environmental contamination from industrial dyes, particularly Methylene Blue (MB), presents a growing challenge due to their toxicity and persistence in aquatic systems. This study explored the catalytic potential of cellulose acetate-stabilized nickel (CA/Ni) nanoparticles for the degradation of MB in aqueous solutions. CA/Ni was synthesized and characterized using FTIR and SEM, confirming its successful incorporation into the cellulose acetate matrix and uniform distribution across the membrane. UV-Vis spectrophotometry was employed to monitor the catalytic degradation of MB, revealing a significant decrease in absorbance at 665 nm over 28 min, indicating 68% degradation efficiency. Kinetic analysis showed that the degradation followed pseudo-first-order kinetics, with an apparent rate constant of 0.0348 min⁻¹ and an R² value of 0.9851, confirming excellent catalytic performance. The effects of temperature and pH on MB degradation were investigated, with the highest efficiency observed at 35 °C and a pH of 7. A room temperature (25 °C) and acidic conditions (pH 5) reduced the degradation rate to 52%. In comparison, a higher temperature (45 °C) and an alkaline pH (pH 9) resulted in a slight decline to 55%, likely due to changes in catalyst efficiency and MB solubility. These findings highlight the potential of Ni NP-stabilized membranes for wastewater treatment applications, providing a scalable and efficient approach to dye removal. Full article

Membrane technology has received great attention in the desalination and water treatment sectors over the last few decades. However, membrane fouling remains a critical issue that affects membrane performance, a phenomenon common in membrane bioreactors (MBRs). This major drawback can be overcome by the preparation of antifouling membranes using an electrospinning technique that generates a hydrophilic modification of membranes. In this study, nanocomposite polyvinylidene fluoride (PVDF) and cellulose acetate (CA) polymer was fabricated to mitigate membrane fouling. Surface and mechanical characterization of the electrospun membrane was performed to assess morphology, chemical composition, and hydrophilic/hydrophobic properties. Anti-fouling performance of the composite PVDF/CA membrane was evaluated versus a neat PVDF membrane through bench-scale experiments. The PVDF/CA nanofiber membrane displayed a more hydrophilic nature, demonstrated by a lower water contact angle (101° vs. 115°) and increased wastewater flux (190 L/m²·h. vs. 160 L/m²·h), although the composite membrane demonstrated lower tensile strength (2.0 ± 0.1 MPa vs. 1.7 ± 0.1 MPa). The new material demonstrated greater anti-fouling performance compared to the neat PVDF membrane. Results suggest that this nanofiber material shows promise as an enhanced antifouling membrane that can overcome membrane fouling limitations. Full article

Adding nanomaterials to polymer membranes can improve certain properties, such as the photocatalytic degradation of contaminants and antibacterial qualities. However, the interaction between nanomaterials and polymers is often limited by the presence of functional groups that can trap nanostructures within the polymer matrix. This study focuses on the synthesis of silver-decorated graphene oxide nanoparticles and their integration into cellulose acetate membranes. Characterization of the membranes was conducted using various techniques, including electron microscopy (SEM), thermogravimetric analysis, FTIR, goniometry, and filterability tests. The results indicate that CA membranes with decorated nanoparticles exhibit improved thermal stability, making them more effective for removing heavy hydrocarbons without the risk of nanomaterial elution during temperature fluctuations in the contaminated water flow subjected to filtration. Furthermore, these decorated structures enhance hydrophobicity due to interactions between the oxygenated groups of GrO and silver ions. While these additional networks may reduce the permeate flow rate, they significantly increase the efficiency of contaminant removal. Full article

The present study investigates the potential of novel mixed matrix membranes that are formed from the biopolymer carboxymethyl cellulose (CMC) and the metal–organic framework ZIF-8 to improve the pervaporation dehydration of isopropanol. The effect of ZIF-8 content variation and porous substrate selection (comprising cellulose acetate (CA) and polyacrylonitrile) on dense and supported membrane properties is systematically investigated using multiple analytical techniques. It is found that ZIF-8 incorporation alters the membrane structure (confirmed by FTIR and NMR), increases surface roughness (observed via SEM and AFM), enhances swelling degree (obtained by swelling measurements), improves surface hydrophobicity (determined by contact angle analysis), and elevates thermal stability (verified by TGA). Quantum chemical calculations are used to validate the interactions between the polymer matrix, modifier, and feed components. The transport properties of developed membranes are evaluated through the dehydration of isopropanol via pervaporation. The cross-linked supported CMC membrane with 10 wt% ZIF-8 prepared on the CA substrate has the optimal performance: permeation flux of 0.136–1.968 kg/(m²h) and ˃92 wt% water in the permeate via the dehydration of isopropanol (water content 12–100 wt%) at 22 °C. Full article

The development of sustainable nanofiltration membranes requires alternatives to petroleum-derived polymer substrates. This study demonstrates the successful use of an eco-friendly cellulose acetate/cellulose nitrate (CA/CN) blend substrate for fabricating high-performance modified thin-film composite (mTFC) membranes. A dense, non-porous polyamide (PA) selective layer was formed via the interfacial polymerization method and modified with 0.05–0.1 wt.% HKUST-1 (Cu₃BTC₂, MOF-199). Characterization by FTIR, XPS, SEM, AFM, and contact angle measurements confirmed the CA/CN substrate’s suitability for TFC membrane fabrication. HKUST-1 incorporation created a distinctive ridge-and-valley morphology while significantly altering PA layer hydrophilicity and roughness. The mTFC membrane performance could be fine-tuned by the controlled incorporation of HKUST-1; incorporation through the aqueous phase slowed down the formation of the PA layer and significantly reduced its thickness, while the addition through the organic phase resulted in the formation of a denser layer due to HKUST-1 agglomeration. Thus, either enhanced permeability (123 LMH bar⁻¹ with 0.05 wt.% aqueous-phase incorporation) or rejection (>89% dye removal with 0.05 wt.% organic-phase incorporation) were achieved. Both mTFC membranes also exhibited improved heavy metal ion rejection (>91.7%), confirming their industrial potential. Higher HKUST-1 loading (0.1 wt.%) caused MOF agglomeration, reducing performance. This approach establishes a sustainable fabrication route for tunable TFC membranes targeting specific separation tasks. Full article

Environmentally friendly biopolymer nanofibrous composite membranes with enhanced mechanical properties and thermal stability were fabricated via electrospinning with different compositions of polylactic acid (PLA) and cellulose acetate (CA). Firstly, PLA and CA composite membranes were prepared and optimized. Then, the optimized membranes were annealed at temperatures ranging from 80 °C to 140 °C, for annealing times between 30 and 90 min. The developed membranes were characterized by FE-SEM, XRD, FR-IT, TGA, DSC, tensile testing, water contact angle, and resistance to hydrostatic pressure. PLA 95-CA 5 was the optimum composite, with a tensile strength 9.3 MPa, an average fiber diameter of 432 nm, a water contact angle of 135.7°, and resistance to a hydrostatic pressure of 16.5 KPa. Annealing resulted in further improvements in different properties. The annealed membranes had thermally stable microporous structures, without shrinkage or deterioration in nanofiber structure, even at an annealing time of 90 min and an annealing temperature of 140 °C. By increasing either the annealing time or temperature, the crystallinity and rigidity of the nanofiber composite membranes were increased. The annealed membrane demonstrated a tensile strength of 12.3 MPa, a water contact angle of 139.2°, and resistance to a hydrostatic pressure of 36 KPa. Electrospinning of PLA-CA composite membranes with enhanced mechanical properties and thermal stability will pave the way for employing PLA-based membranes in various applications. Full article

In seeking alternatives for reducing environmental damage, fabricating filtration membranes using biopolymers derived from agro-industrial residues, such as cellulose acetate (CA), partially dissolved with green solvents, represents an economical and sustainable option. However, dissolving CA in green solvents through mechanical agitation can take up to 48 h. An ultrasonic probe was proposed to accelerate mass transfer and polymer dissolution via pulsed interval cavitation. Additionally, ultrasound-assisted phase inversion (UAPI) on the external coagulation bath was assessed to determine its influence on the properties of flat sheet and hollow fiber membranes during phase inversion. Results indicated that the ultrasonic pulses reduced dissolution time by up to 98% without affecting viscosity (3.24 ± 0.06 Pa·s), thermal stability, or the rheological behavior of the polymeric blend. UAPI increased water permeability in flat sheet membranes by 26% while maintaining whey protein rejection above 90%. For hollow fiber membranes, UAPI (wavelength amplitude of 0 to 20%) improved permeability by 15.7% and reduced protein retention from 90% to 70%, with MWCO between 68 and 240 kDa. This report demonstrates the effectiveness of ultrasonic probes for decreasing the dissolution time of dope solution with green cosolvents and its potential to change the structure of polymeric membranes by ultrasound-assisted phase inversion. Full article

As a porous crystalline material, covalent organic frameworks (COFs) have attracted significant attention due to their extraordinary features, such as an ordered pore structure and excellent stability. Synthesized through the aldehyde amine condensation reaction, TpPa-1 COFs (Triformylphloroglucinol-p-Phenylenediamine-1 COFs) were blended with cellulose acetate (CA) to form a casting solution. The TpPa-1 COF/CA ultrafiltration membrane was then prepared using the non-solvent-induced phase inversion (NIPS) method. The influence of TpPa-1 COFs content on the hydrophilicity, stability and filtration performance of the modified membrane was studied. Due to the hydrophilic groups in TpPa-1 COFs and the network structure formed by covalent bonds, the modified CA membranes exhibited higher hydrophilicity and lower protein adsorption compared with the pristine CA membrane. The porous crystalline structure of TpPa-1 COFs increased the water permeation path in the CA membrane, improving the permeability of the modified membrane while maintaining an outstanding bovine serum albumin (BSA) rejection. Furthermore, the addition of TpPa-1 COFs reduced protein adsorption on the CA membrane and overcame the trade-off between permeability and selectivity in CA membrane bioseparation applications. This approach provides a sustainable method for enhancing membrane performance while enhancing the application of membranes in protein purification. Full article

Deep eutectic solvents (DESs), a novel class of eco-friendly solvents, are attracting considerable attention in extraction techniques. In this study, a hydrophobic DES, created by combining a quaternary ammonium salt and hexanoic acid, was coated onto a commercial cellulose membrane for polycyclic musks (cashmeran, celestolide, galaxolide, and tonalid) microextraction from surface waters followed by gas-chromatography–mass spectrometry (GC MS) analysis. A series of DESs were synthesized and characterized to identify suitable candidates for use as a coating on cellulose membranes. A factorial design approach was employed to investigate key factors, including DES volume, membrane type, dissolving solvent volume, DES incorporation time, and extraction duration, following a preliminary selection of the DES type, membrane, and dissolving solvent. Under optimized conditions, a cellulose acetate membrane impregnated with DES (TBAB:C6, 1:3 molar ratio) was used for 1 h to extract polycyclic musks from surface water; the extract was then dissolved in methanol prior to the GC-MS analysis. The DES-coated membrane demonstrated a linear detection range from 2.5 to 100 μg/L, with limits of detection (LODs) ranging from 0.06 to 0.15 µg/L, while the LOQ values varied from 0.2 to 0.5 µg/L. The validated method was successfully applied to real samples, allowing us to find the presence of galaxolide and tonalide. Full article

In recent times, with the need for a reduction, refinement, and replacement of in vivo animal testing, there has been an increasing demand for the use of relevant in vitro human cell systems in drug development. There is also a great demand for the replacement of skin tissue in various wounds and burns. Furthermore, human skin cell-based in vitro systems can be used to investigate the side effects (toxicity and irritation) and tissue penetration of topical preparations. In this study, exploratory experiments were performed to produce artificial epidermis using two hydrogel scaffolds, alginate and GelMA C. The amount of keratinocytes added to the matrix (10–50–100 × 10⁶/mL) and the duration of tissue maturation (fresh, 1–3–4 weeks) were optimized in an extensive study. The behavior and structure of the two hydrogels were functionally and morphologically assessed. The permeability order for caffeine in the tested barriers was the following: alginate > GelMA C > cellulose acetate membrane > rat skin. It was concluded that GelMA C matrix provides a more favorable environment for cell survival and tissue differentiation (as demonstrated by histology and immunohistochemistry) than alginate. The 3-week incubation and 50 × 10⁶/mL cell number proved to be the most beneficial in the given system. This study provides data for the first time on the multifactorial optimization of two potential skin substitutes for tissue manufacturing. In order to use these results in tissue engineering, the fabricated artificial epidermis preparations must also be optimized for biocompatibility and from physical and mechanical point of views. Full article

This research presents a simple and effective technique to fabricate an optical sensor for ammonia detection, leveraging emission wavelength shifts as the sensing mechanism. The sensor comprises a cellulose acetate matrix doped with Eosin-Y, which serves as the electrospinning material. Photoluminescent micro/nanofibers were successfully fabricated using electrospinning and were stimulated by a 380 nm central wavelength LED. The Eosin-Y-doped electrospun fiber membranes exhibited a red emission peak at 580 nm, allowing ammonia to be detected in the linear concentration range of 0–500 ppm. The experimental results demonstrated a high sensitivity of 8.11, with a wavelength shift sensitivity of 0.029 nm/ppm in response to ammonia concentration changes. This optical sensing method effectively mitigates the influence of fluctuations in excitation light intensity, offering improved reliability. The Eosin-Y-containing electrospun fibers show great potential as a practical sensing material for detecting ammonia gas concentrations with high precision, supporting diverse applications in medical diagnostics, environmental monitoring, and industrial processes. Full article

Membrane processes are a reality in a wide range of industrial applications, and efforts to continuously enhance their performance are being pursued. The major drawbacks encountered are related to the minimization of polarization concentration, fouling, and biofouling formation. In this study, silver nanoparticles were added to the casting solutions of cellulose acetate membranes in order to obtain new hybrid membranes that present characteristics inherent to the silver nanoparticles, namely antibacterial behavior that leads to biofouling reduction. A systematic study was developed to assess the effect of ionic strength, membrane polymeric structure, and silver nanoparticle incorporation on the cellulose acetate (CA) membrane surface charge. Surface charge was quantified by streaming potential measurements and it was correlated with BSA permeation performance. CA membranes were prepared by the phase-inversion method using three casting-solution compositions, to obtain membranes with different polymeric structures (CA400-22, CA400-30, CA400-34). The nanocomposite CA/silver membranes (CA/Ag) were prepared through the incorporation of silver nanoparticles (0.1 and 0.4 wt% Ag) in the casting solutions of the membranes. To evaluate the electrolyte concentration effect on the membranes zeta potential and surface charge, two potassium chloride solutions of 1 mM and 5 mM were used, in the pH range between 4 and 9. The results show that the zeta-potential values of CA/Ag membranes were less negative when compared to the silver-free membranes, and almost independent of the silver content and the pH of the solution. The influence of the protein solution pH and the protein charge in the BSA solutions permeation was studied. The pH conditions that led to the lower permeate fluxes were observed at the isoelectric point of BSA, pH = 4.8. Full article

Cellulose-derived battery separators have emerged as a viable sustainable alternative to conventional synthetic materials like polypropylene and polyethylene. Sourced from renewable and biodegradable materials, cellulose derivatives—such as nanofibers, nanocrystals, cellulose acetate, bacterial cellulose, and regenerated cellulose—exhibit a reduced environmental footprint while enhancing battery safety and performance. One of the key advantages of cellulose is its ability to act as a hybrid separator, using its unique properties to improve the performance and durability of battery systems. These separators can consist of cellulose particles combined with supporting polymers, or even a pure cellulose membrane enhanced by the incorporation of additives. Nevertheless, the manufacturing of cellulose separators encounters obstacles due to the constraints of existing production techniques, including electrospinning, vacuum filtration, and phase inversion. Although these methods are effective, they pose challenges for large-scale industrial application. This review examines the characteristics of cellulose and its derivatives, alongside various processing techniques for fabricating separators and assessing their efficacy in battery applications. Additionally, it will consider the environmental implications and the primary challenges and opportunities associated with the use of cellulose separators in energy storage systems. Ultimately, the review underscores the significance of cellulose-based battery separators as a promising approach that aligns with the increasing demand for sustainable technologies in the energy storage domain. Full article

This study investigated the properties of a novel polymeric membrane based on cellulose acetate, polyethylene glycol/poly(styrene)-b-poly(4-vinylpyridine), and embedded with TiO₂ nanoparticles (CA/PEG/PS₁₅₄-b-P4VP₃₈₁/TiO₂ membrane) obtained by wet-phase inversion method. The TiO₂ nanoparticles fabricated by a hydrothermal method were characterized by XRD, SEM, EDX, and UV-Vis analyses to determine the purity, morphology, and optical band gap energy. The prepared polymeric membranes with and without TiO₂ nanoparticles (CA/PEG/PS₁₅₄-b-P4VP₃₈₁/TiO₂ and CA/PEG/PS₁₅₄-b-P4VP₃₈₁ membranes) were characterized by FTIR, SEM, EDXS, and TGA to observe the effect of TiO₂ nanoparticles added to the polymeric membrane matrix and to analyze the chemical structure, morphology, and thermal stability of the obtained polymeric membranes. The contact angle, SFE, water retention, and porosity were also determined. The results showed that adding the TiO₂ nanoparticles into the polymeric membrane (CA/PEG/PS₁₅₄-b-P4VP₃₈₁/TiO₂) significantly reduced the pore size and the water contact angle, increasing the water retention and the porosity. The lower value of the water contact angle of 15.57 ± 0.45° for the CA/PEG/PS₁₅₄-b-P4VP₃₈₁/TiO₂ membrane indicates a pronounced hydrophilic character. The investigations performed showed that the CA/PEG/PS₁₅₄-b-P4VP₃₈₁/TiO₂ membrane presents excellent properties and can be a promising material for water and waste-water treatment through membrane processes (e.g., electrodialysis, ultrafiltration, nanofiltration, reverse osmosis) in the future. Full article