Preparation Of Ultrafiltration Membranes Research Articles

RETRACTED: Advanced multi-functional regenerative and self-healing tight ultrafiltration membrane for dye/salt wastewater efficient purification

Membrane fouling and membrane damage during membrane operation significantly reduce the permeate flux and separation efficiency, and the preparation of ultrafiltration membranes with renewable and self-healing properties is particularly critical for the sustainable recycling of water resources. Herein, we report a novel tight ultrafiltration membrane, which achieves self-healing properties by incorporating modified β-cyclodextrin (β-CD) monomers into the membrane, forming hydrogel by utilizing UV-induced graft polymerization and covalently binding to the membrane substrate, and then utilizing modified Azo to self-assemble into the hydrophobic cavities of the β-CD via host–guest interactions to construct host–guest chemistry to achieve regenerative anti-fouling properties. In addition, the chemical damage caused by UV-induced during the regeneration process is somewhat avoided by the modified azobenzene (Azo) and β-CD. Taking the renewing membrane as an example, the regeneration test shows that the membrane still has high flux recovery (FRR = 92.5 %) and stable separation performance after three regenerations. Physical self-healing tests showed that the dye/salt rejection recovery of the renewing membrane was greater than 95 % for all four common dyes and salts. In the case of chemical damage, a new peak appears in the XPS at 165.4 eV, demonstrating of the reliability of the actual self-healing of chemical damage. Meanwhile, the results of the mechanical properties of the renewing membrane before and after damage show that the membrane can still maintain high mechanical properties after physical self-healing has occurred. This novel anti-fouling and self-healing tight ultrafiltration membrane for practical high salinity textile wastewater separation has a broad application prospect.

Study on preparation and properties of polyacrylonitrile/jute microcrystalline cellulose ultrafiltration membranes

AbstractPolyacrylonitrile (PAN) is widely used in the preparation of ultrafiltration membranes. However, the hydrophilicity, thermal, and mechanical properties of the PAN ultrafiltration membrane are poor, limiting the applications in water treatment technology. In this study, the hydrophilic jute microcrystalline cellulose (MCC) is utilized as the modifier for the PAN membrane aiming to develop the ultrafiltration membrane with improved performance. The PAN/jute MCC ultrafiltration membranes with varying jute MCC contents are prepared using the phase inversion method and their structure and properties are systematically characterized. The results demonstrate that the hydrophilicity and thermal stability of the PAN membrane are enhanced. Under optimal conditions, compared with pure PAN membrane, the tensile strength and elongation at break of the membrane increase by 22.64% and 9.84%, respectively, and the water flux can reach 88 L/(m2 h), with the bovine serum albumin rejection ratio of 85%. The above results support that jute MCC can improve the performance of the PAN membrane significantly.

A Pd-anchored poly(vinyl chloride-co-maleic acid monoamide)/poly(vinyl chloride) ultrafiltration membrane for the efficient degradation of 4-nitrophenol

Low molecular weight poly(vinyl chloride-co-maleic acid monoamide) was synthesized and blended with PVC to prepare ultrafiltration membranes with improved hydrophilicity and loaded Pd nanoparticles to couple separation and catalysis processes.

Banana Peels Pectin Templated Silica Ultrafiltration Membrane in Disk Plate Configuration Applied for Wetland Water Treatment

South Kalimantan has natural surface water such as wetland water which easily found to prevent water scarcity. Two types of wetland water provided in tropical area i.e. (1) peat water which located in land area; and (2) wetland saline water that area is near to coastal zone. Both are unsuitable for consumption and required to be treated. Ultrafiltration (UF) is one of methods that can be applied for treating natural wetland water using silica membrane. However, it needs improved by carbon due to lacking its low hydrostability properties. This works investigated performance of banana pectin templated silica ultrafiltration membrane in varied operation pressure and feed water treatment. Preparation of ultrafiltration membrane was used banana peels pectin as carbon source that templated into silica sol through sol gel process. Silica pectin xerogel was characterized by Fourier Transformed Infra-red (FTIR) and morphology of silica pectin membrane was characterized by Scanning Electron Microscopy (SEM). The sol is carried out by a coating process to the alumina membrane support on 4 layers. The calcination process is using the Conventional Thermal Processing (CTP) method. Furthermore, the ultrafiltration process run on the dead-end ultrafiltration silica pectin membrane has three functional groups, namely siloxane (Si-O-Si) at a wavelength of 1061 cm-1. silanol (Si-OH) at a wavelength of 966 cm-1 and silica carbon (Si-C) at a wavelength of 795 cm-1. The performance of silica pectin membranes at pressures of 0.5 bar, 1 bar and 1.5 bar in peat water resulted in fluxes of 5.07 kg.m-2.h-1, 11.31 kg.m-2.h-1 and 18.90 kg.m-2.h-1 with rejection of organic matter of 85.56%, 85.49% and 84.68%. Meanwhile in wetland saline water it was 7.04 kg.m-2.h-1, 11.73 kg.m-2.h-1 and 20.52 kg.m-2.h-1 with rejection of organic matter of 82.50%, 79.46% and 78.11%. Salt rejection for wetland saline water for 0.5 bar until 1.5 bar is 84.39%, 82.54% and 81.04%. Ultrafiltration It can be concluded that the increase in pressure affects the performance of the silica pectin membrane where the flux value increases with each increase in pressure, but the rejection value of organic matter and salt rejection show a decreasing.

A new method for tailoring the surface pore size and internal pore structure of ultrafiltration membranes without using additives—Atomization-assisted nonsolvent induced phase separation method

It is highly desired to improve the safety and stability of ultrafiltration (UF) membranes for biotechnology, medicine and food processing by eliminating the use of chemical additives during the membrane preparation process. In this work, a series of high-performance polyacrylonitrile (PAN) UF membranes were prepared continuously by the atomization-assisted nonsolvent induced phase separation (AA-NIPS) method. The pore structure and surface properties of the membranes can be precisely tailored, requiring no chemical additives. The prepared UF membranes are composed of a sublayer of highly interconnected three-dimensional (3D) network structure and a smooth surface layer of uniform small pore structure with a narrow pore size distribution. Compared to UF membranes prepared by the NIPS method, the PAN UF membranes exhibit enhanced water flux and antifouling properties as well as a well-preserved high rejection to bovine serum albumin (BSA). With different atomization pretreatment times, the pure water fluxes of the UF membranes increased by 41 %∼100 %. The AA-NIPS method employed in the present work can effectively modify the porous structure of the membranes without introducing pore-forming additives. The good separation performance, structural controllability, and easy functionalization of the UF membranes make them a promising candidate to be applied in many fields, especially in biotechnology, medicine, and food processing.

Preparation of ultrafiltration membrane from discarded polyethylene terephthalate bottles.

In this study, the polymeric membranes were prepared using discarded polyethylene terephthalate (PET) bottles. The fabrication of the membrane process was carried out using a dope solution composed of polyethylene terephthalate (polymer), O-cresol (as a solvent), and polyethylene glycol 400 (as an additive). The solubility parameters were studied to dissolve the polymer into the solvent at a specific temperature. The melt flow index and thermal analysis were evaluated for the discarded bottles and prepared membranes to ensure the quality and thermal stability of the PET. The porosity of the membranes was determined using scanning electron microscopy. The temperature required to prepare the dope solution was 80°C with a stirring speed of 350rpm. Non-solvent-induced phase separation method was used to fabricate the membranes. The coagulation bath was composed of a water-ethanol mixture. The porosity of the prepared membranes ranges between 30 and 50%. The contact angle was determined for the membrane in the range of 40° to 80°. The flux of the membranes was evaluated using membrane testing cell at a specified pressure which ranges from 80 to 150 Lm-2h-1. The prepared membranes could be used in various industries like dairy, pharmaceutical, juice, and beverages to separate temperature-sensitive substances.

Does substituting reprotoxic solvents during ultrafiltration membrane fabrication really mitigate environmental impacts? Focus on drinking water production

The purpose of this research is to fill knowledge gaps on the relevance of solvent substitution from a life cycle perspective and to put forth relevant operating conditions for possible process optimisation and eco-design. Solvents commonly used to prepare ultrafiltration membranes for drinking water applications are indeed identified by the European REACH regulation for their potential reproductive toxicity and are the subject of research as regards their substitution. Coupling Life Cycle Assessment (LCA) with process modelling allowed to compare conventional membranes (cellulose triacetate as polymer, NMP as solvent) to biosourced membranes (cellulose diacetate as polymer, methyl lactate as solvent). Although methyl lactate fabrication leads to lower environmental scores than NMP fabrication (32% and 10% less GWP100 and ReCiPe Endpoint, respectively), LCA scores for membrane fabrication are similar (1.9 points ReCiPe for 1 m2 membrane) or slightly different, i.e. 11 kg CO2-eq and 9.4 kg CO2-eq for 1 m2 of conventional and biosourced membrane, respectively. From an environmental point of view, solvent substitution has little influence on impacts. Rather, environmental hotspots lie in the operation stage, with impact scores about 10,000 times higher than those of membrane fabrication, which holds out considerable prospects for the optimisation of operating conditions on drinking water plants.

Fabricating novel PVDF-g-IBMA copolymer hydrophilic ultrafiltration membrane for treating papermaking wastewater with good antifouling property.

Ultrafiltration membranes are widely used for the treatment of papermaking wastewater. The antifouling performance of polyvinylidene fluoride (PVDF) ultrafiltration membranes can be improved by changing the hydrophilicity. Here, a novel amphiphilic copolymer material, PVDF grafted with N-isobutoxy methacrylamide (PVDF-g-IBMA), was prepared using ultraviolet-induced Cu(II)-mediated reversible deactivation radical polymerization. The amphipathic copolymer was used to prepare ultrafiltration membrane via NIPS. The prepared PVDF-g-IBMA ultrafiltration membrane was estimated using 1H NMR, FT-IR, and DSC. The contact angle, casting viscosity, and the permeation performance of the PVDF-g-IBMA ultrafiltration membrane were also determined. The pure water flux, bovine serum albumin removal rate, and pure water flux recovery rate of the PVDF-g-IBMA ultrafiltration membrane were 432.8 L·m-2·h-1, 88.4%, and 90.8%, respectively. Furthermore, for the treatment of actual papermaking wastewater, the chemical oxygen demand and turbidity removal rates of the membrane were 61.5% and 92.8%, respectively. The PVDF-g-IBMA amphiphilic copolymer ultrafiltration membrane exhibited good hydrophilicity and antifouling properties, indicating its potential for treating papermaking wastewater.

Polysulfone/Polyetherimide Ultrafiltration composite membranes constructed on a three-component Nylon-fiberglass-Nylon support for azo dyes removal: Experimental and molecular dynamics simulations

Dyeing wastewater from textile industries is often contaminated with chemical pollutants, which causes severe water pollution problems that are challenging to treat. Herein, we report the development of laminated membranes consisted of polysulfone (PSf)/polyetherimide (PEI) layers coated on Nylon-fiberglass-Nylon support by spin/spray-coating technique for the removal of reactive black 5 (RB5) and basic red 18 (BR18) from aqueous solutions via membrane Ultrafiltration (UF). In addition to a pristine polysulfone (PSf) membrane, composite membranes were prepared with 25 wt% (CM25), 30 wt% (CM30), and 35 wt% (CM35) of PEI, and characterized in terms of morphological, wetting, mechanical, and water transport properties along with surface charge and mean pore diameter. Morphological characterization by SEM showed homogeneous and uniform distribution of PSf/PEI membrane layer on the Nylon-fiberglass-Nylon support. Moreover, mechanical tests showed that the stress and strain at the breaking point of membranes were remarkably changed after coating it with Nylon-fiberglass-Nylon support. The addition of PEI had a significant influence on the hydrophilic character of prepared membranes. Filtration results indicated that the incorporation of PEI in composite membranes improved the pure water permeability (PWF) up to 79.11 L m -2 h -1 bar -1 compared to that of PSf alone (29.36 L m -2 h -1 bar -1 ). The combined effect of Nylon-fiberglass-Nylon support and the PSf/PEI membrane layer has certainly enhanced the filtration performance, making prepared UF membranes potential candidates for scale-up industrial applications.

Enhanced hydrophilicity and antifouling performance of PES-C/emodin ultrafiltration membrane

In this article, an ultrafiltration membrane was fabricated from phenolphthalein polyethersulfone (PES-C) modified with emodin using a phase-inversion method. ATR-FTIR and UV-vis analysis showed that emodin had good compatibility with the PES-C ultrafiltration membrane. SEM showed that the prepared ultrafiltration membranes consisted of a porous skin layer and a macroporous support sublayer. The contact angle value of the pure PES-C ultrafiltration membrane was 77.71° and that of the PES-C ultrafiltration membrane blended with 0.105 wt.% emodin decreased to 65.71°, which explained the fact why its pure water flux significantly increased from 190 L/m2·h to 387 L/m2·h. The antifouling properties of the obtained ultrafiltration membranes were assessed by static protein adsorption, bacterial adhesion, antibacterial tests, and filtration experiments with BSA. The PES-C (13.895 wt.%)/emodin (0.105 wt.%) ultrafiltration membrane presented the lowest protein adsorption rate (1.44%), the highest flux recovery ratio (57%), and the largest inhibition zone diameter (3.0 ± 0.06 mm). Compared with that of the pure PES-C ultrafiltration membrane, the bacterial adhesion effect of the PES-C/emodin (0.105 wt.%) ultrafiltration membrane was significantly reduced. In addition, PES-C incorporated into the emodin ultrafiltration membrane had excellent stability in a deionized water system.

Preparation of Ultrafiltration Membrane by Polyethylene Glycol Non-Covalent Functionalized Multi-Walled Carbon Nanotubes: Application for HA Removal and Fouling Control.

Polyethylene glycol (PEG) non-covalent-functionalized multi-walled carbon nanotubes (MWCNT) membrane were prepared by vacuum filtration. The dispersion and stability of MWCNT non-covalent functionalized with PEG were all improved. TEM characterization and XPS quantitative analysis proved that the use of PEG to non-covalent functionalize MWCNT was successful. SEM image analysis confirmed that the pore size of PEG–MWCNT membrane was more concentrated and distributed in a narrower range of diameter. Contact angle measurement demonstrated that PEG non-covalent functionalization greatly enhanced the hydrophilicity of MWCNT membranes. The results of pure water flux showed that the PEG–MWCNT membranes could be categorized into low pressure membrane. PEG-MWCNT membrane had a better effect on the removal of humic acid (HA) and a lower TMP growth rate compared with a commercial 0.01-μm PVDF ultrafiltration membrane. During the filtration of bovine serum albumin (BSA), the antifouling ability of PEG-MWCNT membranes were obviously better than the raw MWCNT membranes. The TMP recovery rate of PEG–MWCNT membrane after cross flushing was 79.4%, while that of raw MWCNT–COOH and MWCNT membrane were only 14.9% and 28.3%, respectively. PEG non-covalent functionalization improved the antifouling ability of the raw MWCNT membranes and reduced the irreversible fouling, which effectively prolonged the service life of MWCNT membrane.

Hollow-fiber membranes of block copolymers by melt spinning and selective swelling

Selective swelling of block copolymers has emerged as an efficient strategy to prepare ultrafiltration membranes with well-defined porosities. However, the application of this strategy is only limited to the preparation of flat-sheet membranes so far. Herein, we extend this selective swelling strategy, for the first time, to the preparation of hollow-fiber membranes (HFMs). A mechanically strong copolymer available at large scale, polysulfone-block-poly(ethylene glycol) (PSF-b-PEG), is employed as the membrane-forming polymer. The PSF-b-PEG melt without any diluters or additives exhibits good fluidity, enabling stable and continuous melt spinning of primary hollow fibers with dense fiber walls. Subsequent selective swelling in the mixture of n-propyl alcohol and acetone produces interconnected nanoporosities throughout the fiber walls, thus forming HFMs with PEG chains enriched on the membrane surface. The wall thicknesses as well as pore sizes, and thus the separation performances of the HFMs are tunable by changing the spinning and swelling parameters. In contrast to the strong hydrophobicity of HFMs prepared by cold stretching of polyolfins, our HFMs possess water-wettable surfaces due to the presence of PEG chains, and can be directly used in aqueous milieu. Because of the PSF-based skeleton and homogenous distribution of nanopores, the HFMs exhibit excellent tensile strengths up to 12.5 MPa, much higher than that of HFMs prepared by the commonly used phase inversion processes. Furthermore, the BSA rejection and water permeance of the HFMs currently can be tuned in the range of 29.9–88.2% and 13.7–119.3 L m-2·h-1·bar-1, respectively, by changing the spinning and/or swelling parameters. Their performances are expected to enhance by optimizing the hollow fiber geometries and pore structures. This strategy neither uses any solvents to fluidize the polymer nor produces wastewater, and therefore is a “cleaner” process. This work not only extends the usages of selective swelling, but also establishes a new process to manufacture HFMs.

Effect of Additive on Microstructure, Hydrophilicity and Ultrafiltration Performance of Polyethylene Terephthalate Membranes

Ultrafiltration is a pressure-driven separation process through a porous membrane that can separate particles or macromolecules from a solution. Ultrafiltration is mostly applied for water treatment processes in various industries such as pharmaceutical, chemical, food and beverage industries. Commercial ultrafiltration membranes are mostly fabricated from polymer materials such as polysulfone, polyethersulfone and cellulose acetate. These polymers are expensive, and for the time being they are not produced in Indonesia. In this work, polyethylene terephthalate (PET) bottle waste was used as the polymer material to prepare ultrafiltration membranes. PET is commonly used as a packaging material for foods and beverages due to its low price and excellent mechanical properties. The PET membranes were prepared via a phase-inversion technique using polyethylene glycol (PEG) as the additive. It was observed that the addition of PEG improved the flexibility and the hydrophilicity of the membranes. The water contact angle decreased to 61.5° by the addition of PEG. The microstructures of the membranes could be controlled by the molecular weight of the PEG. The result of the ultrafiltration experiment showed that the membrane with a high porosity, a large pore size and a high hydrophilicity exhibited a high water permeate flux. In the ultrafiltration experiment using a model feed solution of an aqueous solution containing Bovine Serum Albumin with a molecular weight of 66,000 Da, the membranes showed high rejection values of up to 90% with water permeate fluxes of 14.7 - 23.0 kg/(m2h).

Enhancement in Flux and Antifouling Properties of Polyvinylidene Fluoride/Polycarbonate Blend Membranes for Water Environmental Improvement.

In this work, to overcome the fouling phenomenon of hydrophobic polymer membranes, polyvinylidene fluoride (PVDF) was blended with hydrophilic polycarbonate (PC) to prepare ultrafiltration membranes via the nonsolvent-induced phase separation method. The effects of PC content on membrane morphology, pore size distribution, and surface porosity were characterized and investigated by FE-SEM and image analyzer software. Solubility parameters calculated by molecular dynamics (MD) simulation showed that PVDF and PC are compatible and the results were confirmed by differential scanning calorimetry and wide angle X-ray diffractometry. The long-term chemical stability against NaOH and mechanical property before and after the abrasion test of the prepared membranes were also characterized by dynamic thermomechanical analysis. It was found that the hydrophilicity, water flux, abrasion resistance, and antifouling properties as the performance criteria of polymeric membranes were improved because of the presence of PC, and the separation efficiency of PVDF/PC membranes is much higher than that of the pristine PVDF membrane. The exemplary water filtration performances of these polymer membranes are harnessed here in this work to purify raw water polluted by natural organic matters, addressing the key environmental issue of water contamination.

Single-walled carbon nanotubes grafted with dextran as additive to improve separation performance of polymer membranes

Permeability and selectivity are two important parameters for evaluating membrane separation performance. In this work, the functionalized single-walled carbon nanotubes (DexDTM-g-SCNT) is fabricated by non-covalent interaction using dextran-based macro-chain transfer agent, and used as an additive to blend with polyethersulfone to prepare ultrafiltration membranes via a non-solvent induced phase separation technique. DexDTM-g-SCNT modified membrane has excellent anti-fouling properties, good permeability, and excellent separation performance. Typically, the hydrophilicity of the modified membrane is significantly improved, when the content of additive is 3 wt%. The modified membrane shows high pure water flux of up to 223.3 L m−2h−1, and high rejection ratio for bovine serum albumin, and congo red of 98.5 and 98.8%, respectively. The strategy has great potential for practical applications in water purification and other separation fields.

Fabrication of Composite Ultrafiltration Membrane by Coating Urea Formaldehyde Resin on Filter Paper

Urea-formaldehyde resin (UFR), a thermosetting resin, is used to prepare ultrafiltration membranes because of its excellent mechanical properties and filtration performance. Herein, a porous ultrafiltration membrane is prepared by coating a mixture of UFR and carboxymethylcellulose (CMC) on the surface of filter paper via a facile acid-curing treatment method. CMC is used as a thickening agent, and hydrochloric acid is used as a curing agent to accelerate composite membrane formation. The mesoporous UFR is embedded in the large pores of the paper matrix by coating treatment, and the presence of CMC can decrease the flowability of the resin. The effects of UFR concentration, CMC dosage, and hydrochloric acid concentration on the performance of the composite ultrafiltration membrane are studied. The ultrafiltration membrane demonstrates a rejection rate of 85% and a pure water flux of 850 L/(m2·h) with the optimized resin concentration, CMC dosage, hydrochloric acid concentration, and coating amount at 30%, 20% (resin dry), 12%, and 250 g/m2, respectively.

Assessment of sulfonated homo and co-polyimides incorporated polysulfone ultrafiltration blend membranes for effective removal of heavy metals and proteins

Sulfonated homo and co- polyimide (sPI) were synthesized with new compositional ratios, and used as additives (0.5 wt%, 0.75 wt%, and 1.0 wt%) to prepare blend membranes with polysulfone (PSf). Flat sheet membranes for ultrafiltration (UF) were casted using the phase inversion technique. Surface morphology of the prepared UF membranes were characterized by atomic force microscopy (AFM) and scanning electron microscopy (SEM). Surface charge of the membranes were determined by zeta potential, and hydrophilicity was studied by contact angle measurement. The contact angle of the membrane decreased with increasing sPI additive indicates increasing the hydrophilicity of the blend membranes. Filtration studies were conducted for rejection of heavy metals (Pb2+ and Cd2+) and proteins (pepsin and BSA). Blend membranes showed better rejection than pure PSf membrane. Among the blend membranes it was observed that with increasing amount of sPIs enhance the membrane properties and finally, PSf-sPI5 membrane with 1 wt% of sPI5 showed the improved permeability (72.1 L m−2 h−1 bar−1), and the best rejection properties were found for both metal ions (≈98% of Pb2+; ≈92% of Cd2+) and proteins (>98% of BSA; > 86% of Pepsin). Over all, this membrane was having better hydrophilicity, porosity and higher number of sites to attach the metal ions. Its performance was even better than several-reported sulfonic acid based UF membranes. All these intriguing properties directed this new UF membrane for its potential application in wastewater treatment.

Alumina double-layered ultrafiltration membranes with enhanced water flux

In the present work, γ-alumina double-layered ultrafiltration (UF) membranes with novel gradient pore-sized active layers and single-layered UF membranes were produced using an approach of tightening the pore size of alumina microfiltration (MF) membranes. With the processes of sol-gel, dip coating and sintering, the achieved single- and double-layered UF membranes displayed similar performance in particle size retention, and the double-layered membrane expressed better properties than the single-layered UF membrane in terms of water flux, resistance and anti-fouling. Compared to the MF membrane, the prepared UF membranes displayed improved hydrophilicity and enhanced particle size retention behavior, but lower flux, higher resistance and weaker anti-fouling performance. However, the UF membrane with double layers exhibited values of flux and resistance in the same order of magnitude as those of the MF membrane. The produced alumina double-layered membranes with enhanced flux are of great potential in UF of water.

Improvement on physical properties of polyethersulfone membranes modified by poly(1‐vinylpyrrolidone) grafted magnetic Fe3O4@SiO2 nanoparticles

Polyethersulfone (PES) and poly(1‐vinylpyrrolidone) (PVP) were used to prepare ultrafiltration membranes with grafted Fe3O4 magnetic nanoparticles (PVP‐g‐Fe3O4@SiO2). The structure of synthesized PVP‐g‐Fe3O4@SiO2 was confirmed by FT‐IR and SEM analysis. Physical properties of blend membranes such as thermal resistance, Tensile strength, water uptake, and hydrophilicity were also investigated. Blended membranes of PES/PVP‐g‐Fe3O4@SiO2 have exhibited higher thermal resistance due to increasing the modified nanoparticle content. The hydrophilicity of the synthesized PES/PVP‐g‐Fe3O4@SiO2 membranes also improved by increasing the PVP‐g‐Fe3O4@SiO2 content. As expected, increasing the hydrophilicity of blended membrane, caused enhancement of fouling resistance in membranes. Results showed that the content of PVP‐g‐Fe3O4@SiO2 has different effects on the properties of synthesized composite membranes. Despite increasing the content of PVP‐g‐Fe3O4@SiO2 has a negative effect on elongation, positive effects on maximum stress was observed. Moreover, the water uptake of synthesized membranes was significantly enhanced in comparison to other similar studies.

Effects of GO and MOF@GO on the permeation and antifouling properties of cellulose acetate ultrafiltration membrane

Cellulose acetate (CA) has been used to prepare ultrafiltration membranes because of its excellent properties, especially its biodegradability. To enhance the performance of the CA membrane, the excellent CA ultrafiltration membrane was synthesized by blending with graphene oxide (GO) and HKUST-1 (a metal–organic framework) @GO through the typical phase inversion process. The effects of the different fillers (GO and HKUST-1@GO) on the membrane properties were investigated. Firstly, the fabricated nanocomposites were analyzed through X-ray diffraction, Fourier transform infrared spectroscopy, and scanning electron microscopy. Then, the action of the fillers on the membrane morphology, permeability, separation performance, and antifouling properties were studied. Compared with CA/GO membranes, the CA/MOF@GO membranes exhibit higher hydrophilicity and pure water flux. This is because HKUST-1 can fully exploit the structure advantages of GO and prevent the stacking of GO layers, introducing unique properties to the HKUST-1@GO composite. The CA/MOF@GO0.12 membrane has the highest water permeate flux of 183.51 L m−2 h−1 and also exhibits better antifouling performance than the CA membrane, which possesses a flux recovery ratio of 88.13% and a total fouling ratio of 40.32%. Hence, HKUST-1@GO shows potential as a filler in ultrafiltration membranes to improve their performance for water purification applications.