Cellulose Composite Membranes Research Articles

Copper doped carbon dots modified bacterial cellulose with enhanced antibacterial and immune regulatory functions for accelerating wound healing

The microenvironment of wound healing is susceptible to bacterial infection, chronic inflammation, oxidative stress, and inadequate angiogenesis, requiring the development of innovative wound dressings with antibacterial, anti-inflammatory, antioxidant, and angiogenic capabilities. This research crafted a new multifunctional bacterial cellulose composite membrane infused with copper-doped carbon dots (BC/Cu(II)-RCDs). Findings validated the successful loading of copper-doped carbon dots onto the BC membrane via hydrogen bonding interactions. Compared to the pure BC membrane, the BC/Cu(II)-RCDs composite membrane exhibited significantly enhanced hydrophilicity, tensile properties, and thermal stability. Diverse in vitro assays demonstrated excellent biocompatibility and antibacterial activity of BC/Cu(II)-RCDs composite membranes, alongside their ability to expedite the inflammatory phase and stimulate angiogenesis. In vivo trials corroborated the membrane's ability to foster epithelial regeneration, collagen deposition, and tissue regrowth in full-thickness skin wounds in rats while also curbing inflammation in infected full-thickness skin wounds. More importantly, the treatment of the BC/Cu(II)-RCDs composite membrane may result in the activation of VEGF and MAPK signaling proteins, which are key players in cell migration, angiogenesis, and skin tissue development. In essence, the developed BC/Cu(II)-RCDs composite membrane shows promise for treating infected wounds and serves as a viable alternative material for medicinal bandages.

Construction of Imprinted Bacterial Cellulose Composite Membranes for Selective Adsorption of Cesium from Low Concentration Radioactive Wastewater

Construction of Imprinted Bacterial Cellulose Composite Membranes for Selective Adsorption of Cesium from Low Concentration Radioactive Wastewater

A one-stone-two-birds strategy for cellulose dissolution, regeneration, and functionalization as a photocatalytic composite membrane for wastewater purification

Photocatalytic membranes integrate membrane separation and photocatalysis to deliver an efficient solution for water purification, while the top priority is to exploit simple, efficient, renewable, and low-cost photocatalytic membrane materials. We herein propose a facile one-stone-two-birds strategy to construct a multifunctional regenerated cellulose composite membrane decorated by Prussian blue analogue (ZnPBA) microspheres for wastewater purification. The hypotheses are that: 1) ZnCl2 not only serves as a cellulose solvent for tuning cellulose dissolution and regeneration, but also functions as a precursor for in-situ growth of spherical-like ZnPBA; 2) More homogeneous reactions including coordination and hydrogen bonding among Zn2+, [Fe(CN)6]3− and cellulose chains contribute to a rapid and uniform anchoring of ZnPBA microspheres on the regenerated cellulose fibrils (RCFs). Consequently, the resultant ZnPBA/RCM features a high loading of ZnPBA (65.3 wt%) and exhibits excellent treatment efficiency and reusability in terms of photocatalytic degradation of tetracycline (TC) (90.3 % removal efficiency and 54.3 % of mineralization), oil-water separation efficiency (>97.8 % for varying oils) and antibacterial performance (99.4 % for E. coli and 99.2 % for S. aureus). This work paves a simple and useful way for exploiting cellulose-based functional materials for efficient wastewater purification.

A fully degradable flexible membrane via green synthesis for highly effective separation of oil-water emulsions

Flexible membranes have attracted extensive attention in water treatment due to their outstanding plasticity, portability, and toughness. However, conventional flexible membranes are usually made from non-degradable polymers or hazardous reagents, posing threats to the environment. In this work, a flexible silica nanofiber-regenerated cellulose composite membrane was fabricated by “no polymer solvents electrospinning” with cellulose regeneration. The membrane was fully degradable and eco-friendly, and it exhibited low oil adhesion force and recyclable oil emulsion separation performance. It achieved removal rates of almost 100 % and up to 0.1 % residual oil rate for six different types of oil emulsions with the addition of surfactant, which represents the optimal level reported in the literature to date. The presence of these extremely water-attracting functional groups on the surface of the membrane allows them to bond with water molecules, creating a stable water layer held together by hydrogen bonds. This layer can reject oil compounds during the separation process due to the inherent immiscibility between water and oil. Importantly, this membrane has excellent degradability. The regenerated cellulose layer on its surface can undergo complete microbial degradation (activated sludge) within 7 days, while the remaining substrate can be degraded continuously in concentrated hydrochloric acid, thereby facilitating complete environmentally benign disposal and providing a new strategy for developing green flexible membranes, which holds promise for addressing water scarcity and water pollution issues.

Synthesis and characterization of composite membranes based on bacterial cellulose and coral powder

Preparation of bacterial cellulose and coral powder composite membranes has been carried out. Composite membranes were made by mixing bacterial cellulose with coral powder at different mass ratios at temperatures of 25 ºC, 40 ºC, 60 ºC and At 80 ºC, the composite membrane was evaluated for Fourier Transformation of Infrared, X-Ray Diffraction, degree of swelling, proton conductivity and methanol permeability. From the FT-IR analysis it was found that in the absorption area around 1461.385 – 911cm-1 showing the Si-O-Si stretching functional group, and in the absorption area around 3000 - 3500 cm-1 showing the (O-H) group which shows the semicrystalline composite membrane for each mass variation, according to the results of X-Ray Diffraction. The maximum proton conductivity has been measured as 3.32 x 10-3 S.cm-1 at 60°C, produces a degree of swelling of 31.14% and methanol permeability of 3.72 × 10-9 mol/cm.s for a mass ratio of bacterial cellulose:coral powder composite membrane 4:1.

Functionalizable bacterial cellulose composite membrane for guided tissue regeneration

This research aims to develop guided tissue regeneration (GTR) membranes from bacterial cellulose (BC), a natural polysaccharide-based biopolymer. A double-layered BC composite membrane was prepared by coating the BC membrane with mixed carboxymethyl cellulose/poly(ethylene oxide) (CMC/PEO) fibers via electrospinning. The CMC/PEO-BC membranes were then characterized for their chemical and physical characteristics. The 8 % (wt/v) CMC/PEO (1:1) aqueous solution yielded well-defined electrospun CMC/PEO nanofibers (125 ± 10 nm) without beads. The CMC/PEO-BC membranes exhibited good mechanical and swelling properties as well as good cytocompatibility against human periodontal ligament cells (hPDLs). Its functionalizability via carboxyl entities in CMC was tested using the calcium-binding domain of plant-derived recombinant human osteopontin (p-rhOPN-C122). As evaluated by enzyme-linked immunosorbent assay, a 98–99 % immobilization efficiency was achieved in a concentration-dependent manner over an applied p-rhOPN-C122 concentration range of 7.5–30 ng/mL. The biological function of the membrane was assessed by determining the expression levels of osteogenic-related gene transcripts using quantitative real-time reverse-transcriptase polymerase chain reaction. Mineralization assay indicated that the p-rhOPN-C122 immobilized CMC/PEO-BC membrane promoted hPDLs osteogenic differentiation. These results suggested that the developed membrane could serve as a promising GTR membrane for application in bone tissue regeneration.

Porous rGO/networked cellulose composite membranes: Towards enhanced nanofiltration performance of rGO-based membranes

Graphene-based materials have been widely used for the fabrication of superior separation membranes for water treatment and purification. In particular, reduced graphene oxide (rGO), which has better water stability than graphene oxide (GO), has been demonstrated to be a good building block. However, rGO laminates are characterized by narrow interlayer spacing leading to dense packing and consequently lower flux limiting their direct utilization for membrane development. In this study, we report the fabrication of networked cellulose (NC)/porous rGO composite membranes with enhanced separation performance. We observed a synergistic effect due to the incorporation of NC and the presence of nano-pores on the rGO sheets. Firstly, in addition to the enhanced hydrophilicity and mechanical stability, the presence of NC with networked fibers reduced the horizontal transport resistance within the interlayer channels due to the formation of voids and wrinkles. Secondly, in-plane pores created by H2O2 oxidation of GO effectively contributed to additional transport channels providing shortened transport length for water molecules. Results showed that composite membranes maintained stable long-term performance with a pure water permeance up to 25.1 ± 2.2 Lm−2h−1bar−1 and salt rejection of 70.2 %, 63.08 %, 17.13 % and 25.62 %, for Na2SO4, MgSO4, MgCl2 and NaCl respectively. Unlike many previously reported rGO membranes that rely on ultra-thin selective layers, this work demonstrates an effective strategy for fabricating superior rGO membranes for water treatment and desalination.

The Performance of Cellulose Composite Membranes and Their Application in Drinking Water Treatment.

Water scarcity and water pollution have become increasingly severe, and therefore, the purification of water resources has recently garnered increasing attention. Given its position as a major water resource, the efficient purification of drinking water is of crucial importance. In this study, we adopted a phase transition method to prepare ZrO2/BCM (bamboo cellulose membranes), after which we developed IP-ZrO2/BC-NFM (bamboo cellulose nanofiltration membranes) through interfacial polymerization using piperazine (PIP) and tricarbonyl chloride (TMC). Subsequently, we integrated these two membranes to create a combined "ultrafiltration + nanofiltration" membrane process for the treatment of drinking water. The membrane combination process was conducted at 25 °C, with ultrafiltration at 0.1 MPa and nanofiltration at 0.5 MPa. This membrane combination, featuring "ultrafiltration + nanofiltration," had a significant impact on reducing turbidity, consistently maintaining the post-filtration turbidity of drinking water at or below 0.1 NTU. Furthermore, the removal rates for CODMN and ammonia nitrogen reached 75% and 88.6%, respectively, aligning with the standards for high-quality drinking water. In a continuous 3 h experiment, the nanofiltration unit exhibited consistent retention rates for Na2SO4 and bovine serum protein (BSA), with variations of less than 5%, indicating exceptional separation performance. After 9 h of operation, the water flux of the nanofiltration unit began to stabilize, with a decrease rate of approximately 25%, demonstrating that the "ultrafiltration + nanofiltration" membrane combination can maintain consistent performance during extended use. In conclusion, the "ultrafiltration + nanofiltration" membrane combination exhibited remarkable performance in the treatment of drinking water, offering a viable solution to address issues related to water scarcity and water pollution.

Enhancing Li+ transport via a nanoporous cellulose fiber membrane with an anion-sorbent for high-performance lithium-ion batteries

Cellulose composite membrane facilitates lithium-ion transport between electrodes by the presence of polar groups and anion-sorbent ZIF-67, demonstrating its promising applications in the battery industry.

Biosynthesis and characterization of antibacterial bacterial cellulose composite membrane composed of montmorillonite and exopolysaccharides

Bacterial cellulose (BC), as a natural renewable polymer material, has the advantages of porous nanonetwork structure, high degree of polymerization, high purity, high crystallinity, excellent mechanical properties and biocompatibility. However, BC lacks antibacterial properties, which leads to the limitation of BC material in food packaging and medical materials. In this study, a new antibacterial material using the combination of montmorillonite (MMT), BC and exopolysaccharides (EPS) produced by Weissella confusa H2 was synthesized. Fourier infrared spectroscopy (FT-IR) and X-ray diffraction (XRD) analysis showed that BC-EPS, BC-MMT and BC-EPS-MMT composite membranes conformed to the typical type I cellulose structure. Compared to BC membrane, scanning electron microscopy (SEM) showed that the porosity of BC-EPS, BC-MMT and BC-EPS-MMT composite membranes was low and compact. The physical properties of BC-EPS, BC-MTT and BC-EPS-MTT composite membranes showed lower water vapor transmittance. The BC-MTT and BC-EPS-MTT composite membranes exhibit a lower swelling ratio in 120 min. The thermal properties show that BC-EPS, BC-MTT and BC-EPS-MTT composite membranes have higher thermal stability (352 °C, 310 °C, 314 °C). Additionally, both BC-MMT and BC-EPS-MMT demonstrated strong inhibitory effects against various bacterial strains, including Staphylococcus aureus, Escherichia coli, Salmonella paratyphi A, and Bacillus subtilis. The exceptional properties exhibited by composite membranes establishes them as a highly promising option in the field of food packaging and medical material applications.

Ethyl cellulose composite membranes containing a 2D material (MoS2) and helical carbon nanotubes for efficient solar steam generation and desalination

With the increasing water consumption, water evaporators have been investigated for clean water production. Herein, the fabrication of electrospun composite membrane evaporators based on ethyl cellulose (EC), with the incorporation of light-absorption enhancers 2D MoS2 and helical carbon nanotubes, for steam generation and solar desalination is described. Under natural sunlight, the maximum water evaporation rate was 2.02 kg m−2 h−1 with an evaporation efficiency of 93.2 % (1 sun) and reached 2.42 kg m−2 h−1 at 12:00 pm (1.35 sun). The composite membranes demonstrated self-floating on the air–water interface and minimal accumulation of superficial salt during the desalination process due to the hydrophobic character of EC. For concentrated saline water (21 wt% NaCl), the composite membranes maintained a relatively high evaporation rate of up to ~79 % compared to the freshwater evaporation rate. The composite membranes are robust due to the thermomechanical stability of the polymer even while operating under steam-generating conditions. Over repeated use, they exhibited excellent reusability with a relative water mass change of >90 % compared to the first evaporation cycle. Moreover, desalination of artificial seawater produced a lower cation concentration (~3–5 orders of magnitude) and thereby yielded potable water, indicating the potential for solar-driven freshwater generation.

Low Fouling Nanostructured Cellulose Membranes for Ultrafiltration in Wastewater Treatment

Ultrafiltration (UF) is a common technique used in wastewater treatments. However, the issue of membrane fouling in UF can greatly hinder the effectiveness of the treatments. This study demonstrated a low-fouling composite cellulose membrane system based on microfibrillated cellulose (MFC) and silica nanoparticle additives. The incorporation of 'non-spherical' silica nanoparticles was found to exhibit better structural integration in the membrane (i.e., minimal aggregation of silica nanoparticles in the membrane scaffold) as compared to spherical silica. The resulting composite membranes were tested for UF using local wastewater, where the best-performing membrane exhibited higher permeation flux than commercial polyvinylidene difluoride (PVDF) and polyether sulfone (PES) membranes while maintaining a high separation efficiency (~99.6%) and good flux recovery ratio (>90%). The analysis of the fouling behavior using different models suggested that the processes of cake layer formation and pore-constriction were probably two dominant fouling mechanisms, likely due to the presence of humic substances in wastewater. The demonstrated cellulose composite membrane system showed low-fouling and high restoration capability by a simple hydraulic cleaning method due to the super hydrophilic nature of the cellulose scaffold containing silica nanoparticles.

1-(2-pyridylazo) 2-naphthol-modified bacterial cellulose/multiwall carbon nanotube/silicon dioxide membrane for selectively adsorbed Er (III)

Considering the economic benefits and environmental pollution, it is of great significance to recover rare earth elements from wastewater. In this article, the modified bacterial cellulose is the raw material, and multi-wall carbon nanotubes are added to construct together. The ion imprinting technology is introduced to prepare a silicon-based modified film for the recovery of Er(III) and selectively adsorption function of Er(III) in experiments. The maximum adsorption amount of modified carbon nanotube silicon bacterial cellulose composite imprinted membrane can reach 46.52 mg L−1, and the adsorption capacity is greatly improved compared to other methods that of the non-imprinted membrane. The adsorption efficiency of Er(III) can reach 92%.

Effective single and contest carcinogenic dyes adsorption onto A-zeolite/bacterial cellulose composite membrane: Adsorption isotherms, kinetics, and thermodynamics

This study reports loading of A-zeolite particles on the bacterial cellulose membrane for single and binary carcinogenic dye uptake from the aqueous solution. The bio based membrane was obtained using Gluconobacter Oxydans NRRL 759 in liquid culture medium. Meanwhile, the incorporation of zeolite particles within the bacterial cellulose matrix and on its surface was implemented via in-situ synthesis. The crystallite structure and the morphology of obtained composite membrane were characterized with X-ray diffraction (XRD) and scanning electron microscopy (SEM) hyphenated with energy dispersive X-ray (EDX). The surface characteristics were intensively investigated by N2 adsorption/desorption isotherm, SBET, pore size distribution, and zeta potential. The results indicate that the treatment of bacterial cellulose with zeolite particles reflected two folds in surface area and three folds in the point of zero charge (pHzpc 6.7) compared with un-modified one. The produced composite membrane was also examined against removal of sole cationic methylene blue "MB", and anionic Congo-Red "CR" or in binary solutions included "MB" with Malachite green "MG" or "CR" with different percentages through batch adsorption technique. Different parameters affecting the adsorption process, such as dye concentration, adsorbent type, contact time, temperature, and pH, were optimized. The highest removal was recorded at optimum conditions for sole "MB" dye (99.2%), "CR" dye (81%), binary mixed "2MB/1CR" (96% after 15 min, 91% after 12 h, respectively), and "2MB/1MG" (98.6% after 30 min). Moreover, linear and nonlinear adsorption isotherm models confirmed that MB adsorption and CR obeys Freundlich isotherm model. Also, the kinetic studies revealed that the dyes' adsorption on the composite membrane could be clarified using linear and nonlinear forms of pseudo-first order, pseudo-second order, and intra-particle diffusion models. Thermodynamic findings emphasized the endothermic and spontaneous adsorption process as the adsorbent/ adsorbate physical interaction decreased the entropy. Eventually, the recyclability test revealed that the composite matrix exhibits excellent removal efficiency up to 5 recycles. The primary adsorption mechanism was proposed and confirmed with Fourier transform infrared (FTIR). Finally, the unprecedented composite membrane can be considered as an economically distinguished adsorbent for the removal of not only sol dyes but also mixtures of anionic and cationic dyes.

PVA/CMC/Attapulgite Clay Composite Hydrogel Membranes for Biomedical Applications: Factors Affecting Hydrogel Membranes Crosslinking and Bio-evaluation Tests

Herein, polyvinyl alcohol-carboxymethyl cellulose (PVA-CMC) composite hydrogel membranes were prepared using solution-casting method, where citric acid (CA) was added as crosslinker in different ratios of (7, 10 and12 wt%). Attapulgite clay extracted from Northwestern Desert of Borg El-Arab, Egypt; was incorporated as nanofiller (1, 2, 4, and 5 wt%) into membranes for improving their mechanical/ thermal stability. Results revealed that, physicochemical properties of membranes e.g. swelling%, tensile strength and morphology of membranes affected significantly by different clay concentrations and citric acid crosslinker. Also, attapulgite clay with concentration 1 (wt%) enhanced mechanical strength of composite membranes, compared to other clay concentrations. Furthermore, protein adsorption %, hydrolytic degradation, hemolysis (%) and antimicrobial activity significantly affected by clay contents and CA concentrations. Four bacterial pathogens e.g. Candida albicans, Escherichia coli, Klebsiella pneumoniae, and Bacillus cereus were used for testing antimicrobial activity of prepared membranes. Results referred to increasing of clay contents led to a high hemolysis %; however, increasing CA concentration significantly reduced hemolysis %. Meanwhile, membranes with low clay contents offered the most effective resistance against tested microbes. These findings are referring to the ability of using PVA-CMC-attapulgite composite membranes crosslinked by CA as good candidate of biomaterials for dermal wound dressings.

Strong and robust cellulose-based enzymatic membrane with gradient porous structure in dynamically catalytic removal of sulfonamides antibiotics

Enzyme membrane systems (EMS) have generated considerable interest because of their advantages of accelerating reactions, eliminating product inhibition, and enhancing conversion rates. However, there are deficiencies in the efficient fabrication of affinity carrier membranes and dynamic catalytic separation properties. Herein, a strong and highly flexible spunlaced viscose/bacterial cellulose (BC) composite membrane in situ embedded with graphene oxide (GO) was developed by combining a scalable bio-synthesis method with atom transfer radical polymerization technology. Notably, the layer-by-layer growth of BC on composite film and the addition of GO resulted in an entangled network with strong hydrogen bonding, endowing the resulting membrane with superior mechanical properties and flexibility, while facilitating a gradient structure and porous transport channels. Subsequently, a novel and highly efficient EMS was constructed by using abundant molecular brushes on composite membrane as immobilized enzyme carrier. The resulting EMS exhibited a high throughput (2.17 L/min*m2) and an interception rate (98.64%) in dynamic catalytic sulfonamide antibiotic wastewater activated with syringaldehyde mediator. Meanwhile, the removal rates of sulphapyridine and sulfamethazine were 97.20% and 94.78% under 0.14 MPa and 15 min, respectively. This efficient and scalable manufacturing strategy is of great significance and may pave a novel pathway for antibiotics wastewater treatment and recycling.

Bio-inspired catalytic one-step prepared R-siloxane cellulose composite membranes with highly efficient oil separation

Bio-inspired catalytic one-step prepared R-siloxane cellulose composite membranes with highly efficient oil separation

Polypyrrole/SnCl2 modified bacterial cellulose electrodes with high areal capacitance for flexible supercapacitors

Polypyrrole (PPy)/bacterial cellulose (BC) composite membranes are a promising kind of lightweight and flexible electrodes for supercapacitors. Herein, we explored a facile and efficient electrostatic self-assembly approach to uniformly depositing anion-doped PPy onto positively charged SnCl2-modifed BC (SBC). The obtained PPy@SBC electrode exhibited a high areal capacitance of 5718 mF cm−2 at a current density of 0.5 mA cm−2, a desirable capacitance retention of 83.1% at 5.0 mA cm−2 and excellent cycling stability (a capacitance retention of 86.8% after 10,000 cycles at 10 mA cm−2). A symmetric flexible supercapacitor was further assembled with the PPy@SBC electrodes, which delivered outstanding mechanical flexibility with negligible capacitance decay under different bent states. This study shows impressive potential in fabricating high-performance electrodes for flexible supercapacitors.

SYNTHESIS AND CHARACTERIZATION OF PROTONCONDUCTING MEMBRANES BASED ON BACTERIAL CELLULOSE AND HUMAN HAIR KERATIN

Studies on composite proton-conducting membranes made of human hair keratin and bacterial cellulose have been done. Keratin from human hair is produced through hydrolysis using NaOH as a solvent. Composite membranes constructed of bacterial cellulose and human hair keratin had mass variations of 4.5/0.5, 4.7/0.3, and 4/1. At temperatures of 25 ºC, 40 ºC, 60 ºC, and 80 ºC, the proton-conducting composite membrane was evaluated for Fourier Transform InfraRed, X-Ray Diffraction, degree of swelling, and proton conductivity. The interaction of bacterial cellulose and human hair keratin appeared at the peak of 3000-3500 cm-1, as evidenced by functional group analysis of bacterial cellulose and human hair keratin composite membranes from Fourier Transform InfraRed. The produced composite membrane was semicrystalline in each mass variation, according to the results of the X-Ray Diffraction examination. The variant of bacterial cellulose and human hair keratin 4/1 showed the highest degree of swelling (34.09%). The composite membrane keratin made of bacterial cellulose and human hair had the maximum proton conductivity, with a variation of 4/1 and a value of 3.673 x 10-5 S/cm at a temperature of 25 ºC.

Removal of Cr(III) from Aqueous Solution Using Labeo rohita Chitosan-Based Composite

This study focusses on the synthesis of chitosan-cellulose composite membrane derived from Labeo rohita fish scales (FS) for the removal of Cr(III) from aqueous solution, while chromium is a serious threat to groundwater. Waste FS are valorized to chitosan by demineralization, deproteination, and deacetylation successively. Cellulose was extracted from sugarcane bagasse using acidic hydrolysis. Chitosan-based cellulose composite porous membrane was fabricated by evaporating solvent from polymer solution in petri dish. The impact of pH, contact time, and absorbent dosage on the removal of Cr(III) from an aqueous solution was investigated. Atomic absorption spectrophotometer was used to check the Cr(III). Results showed that chitosan comprising 85% degree of deacetylation was achieved by alkali treatment, while yield was 22%. FTIR analysis confirmed the chitosan and chitosan-cellulose-based composite membrane. Morphology studies showed that the cellulose was strongly staggered and due to the chitosan, the surface of cellulose became rougher, which is good to enhance the adsorption capacity. The maximum removal 57% of Cr(III) from aqueous solution was observed at pH 6 at 60 min and 50 mg dosage of adsorbent. The minimum removal (47%) of Cr (III) was found at pH 2. These results confer that Labeo rohita-based chitosan-cellulose composite membrane has great potential for the removal of metals from industrial effluents.