Modified Cellulose Acetate Membranes Research Articles

Hydrophobic Modification of Cellulose Acetate and Its Application in the Field of Water Treatment: A Review

With the inherent demand for hydrophobic materials in processes such as membrane distillation and unidirectional moisture conduction, the preparation and application development of profiles such as modified cellulose acetate membranes that have both hydrophobic functions and biological properties have become a research hotspot. Compared with the petrochemical polymer materials used in conventional hydrophobic membrane preparation, cellulose acetate, as the most important cellulose derivative, exhibits many advantages, such as a high natural abundance, good film forming, and easy modification and biodegradability, and it is a promising polymer raw material for environmental purification. This paper focuses on the research progress of the hydrophobic cellulose acetate preparation process and its current application in the water-treatment and resource-utilization fields. It provides a detailed introduction and comparison of the technical characteristics, existing problems, and development trends of micro- and nanostructure and chemical functional surface construction in the hydrophobic modification of cellulose acetate. Further review was conducted and elaborated on the applications of hydrophobic cellulose acetate membranes and other profiles in oil–water separation, brine desalination, water-repellent protective materials, and other separation/filtration fields. Based on the analysis of the technological and performance advantages of profile products such as hydrophobic cellulose acetate membranes, it is noted that key issues need to be addressed and urgently resolved for the further development of hydrophobic cellulose acetate membranes. This will provide a reference basis for the expansion and application of high-performance cellulose acetate membrane products in the environmental field.

Biomass-Derived Cellulose Acetate Membranes Modified with TiO2/Graphene Oxide for Oil-In-Water Emulsion Treatment.

Considering the environmental impact and health risks caused by oily wastewater in the petrochemical industry, it is crucial to develop more efficient separation techniques than traditional methods, such as membrane separation, for treating stable emulsions enriched with natural surfactants. This study investigated the preparation of dense cellulose acetate membranes from a low-cost biomass precursor (Luffa cylindrica) and their modification with graphene oxide (GO) and TiO2 nanoparticles, aiming to obtain a polymeric nanocomposite with good flux characteristics and selectivity for the treatment of oil/water emulsions. The materials obtained were characterized using techniques such as X-ray diffraction, nuclear magnetic resonance spectroscopy, infrared absorption spectroscopy, along with optical and scanning electron microscopy, among others. The membranes were prepared by the casting technique and modified with the above-mentioned nanostructured materials. Flux analyses with petroleum emulsion revealed that membranes modified with GO and TiO2 nanoparticles showed significant improvements in antifouling resistance compared to unmodified membranes. These enhanced properties highlight the potential of modified cellulose acetate membranes for application in industrial wastewater treatment.

Mixed‐charge cellulose nanocrystal modified cellulose acetate membrane with endotoxin scavenging ability and antibacterial properties

AbstractBlending modification is used to improve the hemocompatibility of cellulose acetate (CA) dialysis membranes while endowing the CA membrane with endotoxin scavenging and antibacterial capabilities. First, polydopamine (PDA) and polyethylenimine (PEI) are used as negatively charged and positively charged moieties, respectively, together with cellulose nanocrystals (CNCs) to construct mixed charge CNCs (PEI‐PDA@CNCs). Then PEI‐PDA@CNCs is blended with the CA casting solution, and the modified CA dialysis membrane is prepared through a phase inversion process. Through biocompatibility, adsorption, antibacterial, and filtration experiments, various properties of PEI‐PDA@CNCs modified CA membrane (PDCA) are systematically tested. The results show that the PDCA membrane exhibited good blood compatibility and noncytotoxicity. At the same time, the PDCA membrane has antibacterial properties and excellent endotoxin adsorption capacity. Compared with the CA membrane, the clearance rates of PDCA membrane for Staphylococcus aureus and Escherichia coli reach 54.0% ± 1.5% and 52.9% ± 5.9% respectively. In the dynamic adsorption experiment, the adsorption capacity of PDCA membrane for endotoxin increases to 2322.1 ± 45.9 EU/g. The research results indicate that PEI‐PDA@CNC‐modified multifunctional CA membrane with endotoxin adsorption and antibacterial properties has potential application prospects in the fields of hemodialysis and blood purification.

Novel in-situ zwitterionization of carbon quantum dots on membrane surface for oil/water separation

Industrial growth led to an increase in the release of hazardous oily wastewater that seriously threatens human health and the ecosystem. Developing polymeric membranes for treating such wastewater has garnered significant attention, yet their fouling resistance remains a challenge. In this study, an anti-fouling zwitterionic cellulose acetate (CA) membrane, called ZQDs-g-CA, was fabricated by grafting carbon quantum dots (CQDs) on the surface of the CA membrane, followed by zwitterionization of CQDs (Zwitterionic carbon quantum dots, ZQDs). The grafting of ZQDs increased the hydrophilicity and oleophobicity of the membrane due to the hydrophilic functional groups present in the nanomaterial. The surface roughness was increased, allowing a greater surface area for contact between water molecules and the membrane. The modified CA membrane demonstrated excellent water flux (602.2 ± 30.2 L m−1 h−1 bar−1 (LMHB)) and oil/water emulsion separation performance, with a permeation flux of 426.1 ± 9.6 LMHB and oil rejection of 99.4 %. Additionally, the anti-fouling tests demonstrated remarkable performance with more than 96 % flux recovery ratio (FRR), 30.35 % reversible fouling ratio (Rr), and 3.05 % irreversible fouling ratio (Rir). The results showed that the in-situ ZQDs on the CA membrane exceeded the 96 % rejection rate for different oil/water emulsions. ZQDs were successfully applied on the CA membrane, which would provide a reference for the application of ZQDs-g-CA in oil/water separation.

Utilization of green resource-based Mimosa pudica hydrogel powder in a cellulose acetate-based polymeric membrane as absorbent: a sustainable approach towards female hygiene application

This research explores the potential of incorporating Mimosa pudica hydrogel powder into a modified cellulose acetate membrane, enhancing its properties as an absorbent material for female hygiene applications.

Green Synthesis of Citric Acid-Crosslinked Cellulose Acetate Membrane for Polymer Electrolyte

Safer alternative for lithium-ion battery containing liquid electrolyte was proposed using solid polymer electrolyte as a combo separator/electrolyte. In this work, cellulose acetate (CA) was used to replace fossil-based polymer as battery separator. To further promote sustainable membrane fabrication, dimethylsulfoxide (DMSO) and citric acid was used as solvent and cross-linking agent, respectively. Branched polyethyleneimine (bPEI) was also incorporated in the polymer electrolyte complex to promote electrolyte salt dissociation within the matrix. Crosslinking of CA-bPEI using citric acid showed promising properties compared to unmodified CA membrane. Better thermal stability and lower crystallinity were seen in the modified CA membrane, resulting in better ionic conductivity.

Biosensor based on Cellulose Acetate/Glutaraldehyde Membrane Electrodes for detection of organophosphorus pesticides

In recent years, sensor applications have been critical in many fields, especially food safety and pesticides. Organophosphorus pesticides (OPPs) can be detected using a potentiometric biosensor with a membrane electrode made of a new natural material based on cellulose acetate (CA). Acetylcholinesterase was immobilized to 15% modified CA membrane electrodes using glutaraldehyde (GTA) as crosslinking agent and gold (Au) electrode. An indirect method used an acetylthiocholine chloride (ATCl) substrate to find OPPs like chlorpyrifos, profenophos, and diazinon. The working electrode was an CA/GTA membrane electrode, and the reference electrode was an Ag/AgCl electrode, whose potential value was measured with a potentiometer. The surface morphology of the biosensor membrane was investigated using scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM/EDX). It showed that the CA membrane has a smooth, porous surface and is very dense, and its structure consists of 71.27% carbon (C) and 28.73% oxygen (O) with an average diameter of 562.33 nm. A potentiometric biosensor based on AChE inhibition for the detection of OPPs showed a limit of detection (LoD) of 1×10−6 μg/L with a linearity range of 1×10−6–1.0 μg/L. The %inhibition value for the chlorpyrifos pesticide was 14.44 to 73.08%, profenophos was 11.98 to 77.98%, and diazinon was 18.58 to 83.27%. Therefore, higher inhibitor concentrations (OPPs) have a greater ability to prevent the AChE enzyme from breaking down the acetylcholine substrate. The biosensor with the CA membrane has a wide linearity range and a low detection limit. The potentiometer rapidly detects pesticide residues.

Efficient removal of bovine serum albumin from water by cellulose acetate membranes modified with clay and titania nano particles.

Modified cellulose acetate membranes with bentonite clay (CA/bent) and TiO2 nanoparticles (CA/TiO2) using the phase inversion method are successfully prepared and characterized. These Membranes are favored due to their high salt rejection properties and recyclability. The IR and EDX spectral data indicate the formation of modified membranes. The Scan Electron Microscope micrographs show that the modified membranes have smaller particle sizes with higher porosity than the neat membrane. The average pore diameter is 0.31µm for neat cellulose acetate membrane (CA) and decreases to 0.1µm for CA/0.05bent. All modified membranes exhibit tensile strengths and elongation percentages more than the neat membrane. The higher tensile strength and the maximum elongation% are 15.3N/cm2 and 11.78%, respectively, for CA/0.05bent. The thermogravimetric analysis of modified membranes shows higher thermal stability than the neat membrane. The modified membranes exhibit enhanced wettability and hydrophilicity compared with cellulose acetate, by measuring the contact angle which decreases from 60° (CA) to 40° (CA/0.1bent). The ultrafiltration tests indicated that the CA/bent and CA/TiO2 are better than CA. The most efficient nanocomposite membrane is CA/0.05bent with 100% removal of (BSA) from industrial water with a flux equal to 9.5mL/min under an applied pressure of 20bar. Thus, this study introduces a novel ultrafiltration membrane (CA/0.05bent) that can be used effectively to completely remove bovine serum albumin from contaminated water.

PRODUCTION OF CELLULOSE ACETATE MEMBRANE FROM COCOA (THEOBROMA CACAO L) SHELL MODIFIED POLYETHYLENE GLICOL FOR PB METAL ION FILTRATION

In this study, a modified polyethylene glycol modified cellulose acetate membrane was made. Cellulose acetate was synthesized from cocoa husk waste (Theobroma cacao L) with several steps, namely isolation of alpha cellulose from cocoa husk waste, synthesis of cellulose acetate from alpha cellulose, preparation of 10% cellulose acetate membrane with the addition of polyethylene glycol 0, 5, 10, 15, 20 & 25% . From the results of the research, it was found that the FT-IR analysis of -cellulose from cocoa shells showed an absorption peak at wave numbers between 3400 – 3500 cm-1 which indicated the presence of O-H stretch groups. At wave numbers 2800-2900 cm-1 indicates C-H stretching, then it can be seen at wave numbers 1160 cm-1 indicates C-O-C stretching, and at 1035-1060 cm-1 indicates C-O stretching. In the fingerprint area, we found absorption peaks at wave numbers around 1300 cm-1 which indicated the presence of C-H bending and around 1400 cm-1 indicating the presence of CH2 bending. The cellulose acetate obtained is white and smooth compared to alpha cellulose. At the membrane preparation stage, the results of the insoluble cellulose acetate & PEG using acetone as a solvent. So it is necessary to do a solubility test and find a suitable solvent to form polyethylene glycol modified cellulose acetate membrane for Pb metal ion filtration.

Modified Cellulose Acetate Membrane for Industrial Water Purification

Modified Cellulose Acetate Membrane for Industrial Water Purification

Experimental investigation of polysulfone modified cellulose acetate membrane for CO2/H2 gas separation

Experimental investigation of polysulfone modified cellulose acetate membrane for CO2/H2 gas separation

Synthesis and Characterization of Blended Cellulose Acetate Membranes.

The casting and preparation of ultrafiltration ZnO modified cellulose acetate membrane (CA/ZnO) were investigated in this work. CA membranes were fabricated by phase inversion using dimethylformamide (DMF) as a solvent and ZnO as nanostructures materials. Ultrafiltration (UF) performance, mechanical stability, morphology, contact angle, and porosity were evaluated on both CA- and ZnO-modified CA samples. Scanning electron microscopy (SEM) was used to determine the morphology of the membranes, showing different pore sizes either on rough surfaces and cross-sections of the samples, an asymmetric structure and ultra-scale pores with an average pore radius 0.0261 to 0.045 µm. Contact angle measurements showed the highest hydrophobicity values for the samples with no ZnO addition, ranging between 48° and 82.7° on their airside. The permeability values decreased with the increasing CA concentration in the casting solution, as expected; however, ZnO-modified membranes produced lower flux than the pure CA ones. Nevertheless, ZnO modified CA membranes have higher surface pore size, pore density and porosity, and improved surface hydrophilicity compared with pure CA membranes. The results indicated that the incorporated nano-ZnO tends to limit the packing of the polymer chains onto the membrane structure while showing antifouling properties leading to better hydrophilicity and permeation with consistent UF applications.

Preparation and Characterization of 18-Crown-6 Modified Cellulose Acetate Membrane in Uni-Univalent Aqueous Electrolyte Solutions

In present study, a cellulose acetate/18-crown-6 blend membrane (selective for K+ ions) was prepared by the solvent vapourization method. The surface morphology of the modified membrane was characterized by scanning electron microscopy (SEM) analysis, which indicate the smooth and homogeneous membrane surface. The effect of water and electrolyte (KCl and NaCl) concentration on the rate of water sorption and porosity was explained on the basis of physico-chemical parameters i.e. water content and water activity of the membrane phase. The variation of ionic transport number with respect to water activity, i.e. [dtmK+/dam w > dtmNa+/dam w] has been observed in the present system. The transport of ions under concentration gradient in term of permeability, flow and flux was estimated by membrane/solution conductance-time data. The variations of permeability, flux and flow values with respect to time for K+ and Na+ ions were found to be different. Membrane water activity (am w) decreases with the increase of external electrolyte concentration. The effective fixed charge density of the membrane increases with increase of external electrolyte concentration. Permselectivity parameter of the membrane in both cases decline with increase of external electrolyte concentration.

Performance of Annealed Composite Cellulose Acetate/NaA Zeolite Membrane in Carbon dioxide/Methane Gas Separation

Ramie (Boehmeria nivea) is one type of plant used to produce high quality cellulose fiber. Its fiber is convertible to cellulose acetate (CA), which is commonly used as membrane’s material. Dense CA membrane is used in gas permeation process and the performance is improvable by mineral blending and annealing. This study aims to determine the characteristics of modified CA membranes and the performance in separation of CO2/CH4 gases. Membrane preparation was carried out by using phase inversion technique, while annealing was carried out at 60oC. Furthermore, NaA zeolite was added with various concentrations, which include 5, 10, 15 and 20%. Gas permeation was carried out at 4 barrer for an hour. The performance of the membrane was measured based on its permeability and selectivity. The results showed that CA membrane with 10% zeolite yielded the best performance with CO2 and CH4 permeability of 140.55 and 22.25 barrer respectively and selectivity of CO2/CH4 6.32.

A novel membrane based on cellulose acetate nanofibers with a ZrO2 reinforcement layer for advanced sodium-ion batteries

A novel ZrO2-reinforced nanofibrous membrane for sodium-ion batteries was synthesized via fabricating a ZrO2-reinforced layer on the surface of the modified cellulose acetate membrane (MCA) by a new and simple in-situ chemical precipitation method. Upon the rational design, the ZrO2-reinforced nanofibrous membranes exhibit high chemical stability and excellent wettability (a decreased contact angle from 26.8° to 7.4°) in electrolytes. Moreover, the ZrO2-reinforced nanofibrous membranes also show no distinct dimensional change after being kept at 250 °C for 30 min and high tensile strength up to 1.15 MPa. Compared to that of the MCA membrane (1.61 mS cm−1), the ZrO2@MCA-0.5h (immersed in a ZrO(NO3)2 solution for 0.5 h) exhibits a high ionic conductivity of 2.23 mS cm−1. Additionally, the cell with the ZrO2@MCA-0.5h displays a high discharge capacity of 224.8 mAh g−1 at 0.5 C, which are higher than those of the MCA membrane (156.1 mAh g−1). Meanwhile, the rate performance of the cells assembled with the ZrO2-reinforced nanofibrous membranes, especially with the ZrO2@MCA-0.5h membrane，are also better than that of the MCA. All the above improvements can be attributed to the presence of the continuous-phase ZrO2 reinforcement layer fabricated on the surface of the MCA membrane, which forms a strong self-adhesive structure among fibers to enhance mechanical strength and has a good affinity for the electrolyte to obtain high ionic conductivity.

Increased performance and antifouling of mixed-matrix membranes of cellulose acetate with hydrophilic nanoparticles of polydopamine-sulfobetaine methacrylate for oil-water separation

Emerging technologies for treating oily wastewater employ ultrafiltration membranes that incorporate hydrophilic nanoparticles for enhanced effectiveness and efficiency. In this study, cellulose acetate (CA) mixed-matrix membranes with zwitterionic nanoparticles—polydopamine-sulfobetaine methacrylate or P(DA-SBMA)—were fabricated through wet-phase inversion. The ratio of SBMA to DA monomers was varied to alter the size of P(DA-SBMA) nanoparticles. Adding P(DA-SBMA) to a CA solution led to thermodynamic instability, which resulted in turn in instantaneous demixing during the phase separation in water. The effect was favorable on the membrane porosity and mean pore radius. Moreover, the membrane hydrophilicity was improved because of the abundance of hydrophilic functional groups present in P(DA-SBMA) nanoparticles. A suitable size and content of P(DA-SBMA) nanoparticles embedded in the CA matrix produced a modified CA membrane that delivered optimal water flux of 583.64 ± 25.12 L m−2 h−1. Flux recovery and reversible fouling were enhanced by 8.85% and 11.10%, respectively, whereas irreversible fouling decreased by 8.85%. Different oil-in-water emulsions containing diesel oil, dodecane, food-grade oil, toluene, and hexane were subjected to tests, and high separation efficiencies (95–99%) were achieved. Overall, the fabricated membranes were effective in treating different types of oily wastewater.

Surface modified cellulose acetate membranes for the reactive retention of tetracycline

This paper presents a new method for the reactive retention of tetracycline from aqueous solutions. For this, cellulose acetate membranes were functionalized with aminopropyl triethoxysilane, followed by reaction of the reaming free amino groups with cyanuric chloride. The reactive retention process is based on passing through the membrane heated feed solution which contains tetracycline. The amino group from tetracycline will react with a chlorine atom from the cyanuric chloride. The synthesized materials were characterized by Scanning Electronic Microscopy, Thermogravimetric Analysis, FT-IR and X-ray Photoelectron Spectroscopy, proving both the material synthesis and also the antibiotic bonding during the separation process. Retention studies were evaluated using UV–Vis Spectroscopy on pre-and post-membrane feed solutions. The water flux with pure water has also been conducted. The modified CA membrane showed an increase of the adsorption capacity from 16% to 88% and an improved permeability from 72 L·m−2·h−1 to 517.66 L·m−2·h−1 compared with pure CA membrane.

Membrane fouling mitigation for enhanced water flux and high separation of humic acid and copper ion using hydrophilic polyurethane modified cellulose acetate ultrafiltration membranes

The presence of both copper ion (Cu (II)) from industry and humic acid (HA) in natural waters may generate Cu (II)–HA complex, which is a non-biodegradable and toxic organic pollutant in the water. Removal of such toxic substance is of great importance and environmental significance. Although membrane technology provides a solution for the removal via the filtration, fouling still presents a major challenge for the effective separation. In this study, polyurethanes endcapped with β-cyclodextrin and lactic acid were synthesized and used as additives to be blended with cellulose acetate membranes, which possessed enhanced hydrophilicity, permeability and antifouling property for the removal of Cu (II) and HA. As an example, the polyurethane endcapped with lactic acid (LPU-CA) membrane exhibited high pure water flux (PWF) of 648 L m−2 h−1, as well as high flux recovery ratios (FRRs) of 97.8% and 92% and low irreversible fouling rate (Fir) of 2.2% and 7.8% for the ultrafiltration (UF) of HA and Cu (II)–HA complex, respectively, showing excellent anti-fouling performance. In addition, the Cu (II) and HA rejection was greatly enhanced by the HA enhanced complexation process. These results indicated that the polyurethanes modified cellulose acetate membrane provided enhanced separation with good antifouling property, which can be potentially used for the cleaning of the toxic metal-organic pollutants in wastewaters.

Air to Air Energy Recovery from HVAC Systems under Different Membrane Materials

Membrane heat exchanger is one of the main components of green HVAC systems. Performance of a thin-membrane heat exchanger has been examined for different membrane materials. A computational fluid dynamics (CFD) approach was utilized to conduct the current study. The CFD model consisted of a single channel for hot stream and another channel for cold stream. Four membranes were investigated: 45 gsm and 60 gsm Kraft paper, modified cellulose acetate membrane and PVA/LiCl blend membrane. Obtained values of thermal effectiveness at typical HVAC system conditions showed that different membrane materials produced different thermal performance values. The amount of energy recovered from the modified cellulose acetate membrane heat exchanger was the highest. Finally, heat exchanger performance is found to be very sensitive to ambient air relative humidity variation.

Effect of Polyvinyl Pyrolidone on Morphology and Performance of Cellulose Acetate Based Dialysis Membrane

Polyvinyl pyrolidone (PVP) was added as filler in cellulose acetate (CA) to produce mixed matrix membrane (MMM) for hemodialysis operation. Phase separation induced by diffusion (DIPS) was used for fabrication of mixed matrix CA/PVP flat sheet membranes. The effect of adding PVP was investigated on the morphology and permeation efficiencies of CA membranes. The surface arrangement of polymer and additives in pure and blended membrane was studied by FTIR, contact angle and SEM. Results revealed homogenous and significant mixing of PVP content into pure CA matrix. Performance efficiency of blended membranes was investigated by means of pure water flux (PWF), urea clearance and % rejection of bovine serum albumin (BSA). The observable decrease of contact angle from 83° to 69° in CA/PVP MMM membranes of varying composition effectively revealed enhancement in hydrophilicity of MMM membrane surface. For protein rejection, all CA/PVP membranes rejected>90% of BSA relative to 25% for pure CA membrane. Furthermore, urea clearance behavior for CA/PVP membranes was 62.4% in comparison to 52% for pure CA membrane. The incorporation PVP i.e 1% by weight (Mpvp1) significantly improved the hydrophilicity, PWF, BSA rejection and urea clearance percentages of modified CA membrane for dialysis application.