Polyethersulfone Ultrafiltration Membranes Research Articles

A Comparison Study for The Performance of Polyethersulfone Ultrafiltration Mixed Matrix Membranes in The Removal of Heavy Metal Ions from Aqueous Solutions

Polyethersulfone (PES) ultrafiltration membrane blending NaX zeolite crystals as a hydrophilic additive was examined for zinc (II) and lead ions Pb (II) removal from aqueous solutions. The effect of NaX zeolite content on the permeation flux and removal efficiency was studied. The results showed that adding zeolite to the polymer matrix enhanced the permeation flux. The permeation flux of all the zeolite/PES matrix membranes was higher than the pristine membrane. No significant improvement was observed in the removal of Zn (II) ions using all prepared membranes as the removal percentage did not raise above 29.2%. However, the removal percentage of Pb (II) ions was enhanced to 97% using a membrane containing 0.9%wt. zeolite. Also, it was found that this membrane has a higher ion exchange capacity than the other prepared membranes. Two isotherm models (Langmuir model, and Freundlich model) were employed in the analysis of the ion exchange equilibrium data. The experimental data best fitted the Langmuir model with R2 of 0.889 than the Freundlich model.

Doubly modified MWCNTs embedded in polyethersulfone (PES) ultrafiltration membrane and its anti-fouling performance

Abstract Multiwall carbon nanotubes (MWCNTs) are often used to modify polymer membranes as additives, however, MWCNTs are easy to agglomerate and entangle in polymer matrix due to their own strong van der Waals force. MWCNTs were doubly modified by bonding octadecylamine (ODA) and SiO2 through the respective amidation and esterification reactions to prepare SiO2-MWCNT-ODA nanocomposites. The amino groups on ODA were amidated with the carboxyl groups on MWCNT-COOH. Then the hydroxyl groups on SiO2 were bonded to MWCNT-COOH through esterification to obtain SiO2-MWCNT-ODA nanocomposites. PES/SiO2-MWCNT-ODA composite ultrafiltration (UF) membrane was prepared by non-solvent induced phase separation (NIPS) method. SiO2-MWCNT-ODA nanocomposites and PES/SiO2-MWCNT-ODA membrane were characterized by FTIR, XRD, TGA, and SEM, etc. The results showed that PES/SiO2-MWCNT-ODA membrane had significantly improved permeability, rejection, and antifouling properties for comparison with PES membrane. The pure water flux of PES/Nano.2-0.5 reached 212.5 L m−2 h−1, which was approximately 2.6 times than that of PES membrane, and the rejection of BSA protein for composite membrane was as high as 94.2%. PES/SiO2-MWCNT-ODA composite membrane had excellent antifouling performance and the flux recovery rate (FRR) of PES/Nano.2-0.5 membrane could still maintain at higher value of 84.82% after two cycles in the antifouling test.

Ultrafiltration Membranes Functionalized with Copper Oxide and Zwitterions for Fouling Resistance.

Polymeric membrane fouling is a long-standing challenge for water filtration. Metal/metal oxide nanoparticle functionalization of the membrane surface can impart anti-fouling properties through the reactivity of the metal species and the generation of radical species. Copper oxide nanoparticles (CuO NPs) are effective at reducing organic fouling when used in conjunction with hydrogen peroxide, but leaching of copper ions from the membrane has been observed, which can hinder the longevity of the CuO NP activity at the membrane surface. Zwitterions can reduce organic fouling and stabilize NP attachment, suggesting a potential opportunity to combine the two functionalizations. Here, we coated polyethersulfone (PES) ultrafiltration membranes with polydopamine (PDA) and attached the zwitterionic compound, thiolated 2-methacryloyloxyethyl phosphorylcholine (MPC-SH), and CuO NPs. Functionalized membranes resulted in a higher flux recovery ratio (0.694) than the unfunctionalized PES control (0.599). Copper retention was high (>96%) for functionalized membranes. The results indicate that CuO NPs and MPC-SH can reduce organic fouling with only limited copper leaching.

Novel Water-Soluble Poly(terephthalic-co-glycerol-g-fumaric acid) Copolymer Nanoparticles Harnessed as Pore Formers for Polyethersulfone Membrane Modification: Permeability–Selectivity Tradeoff Manipulation

This work presents poly(terephthalic-co-glycerol-g-fumaric acid) (TGF) as a novel water-soluble polymeric nano-additive for the modification of a polyethersulfone ultrafiltration membrane. The TGF was harnessed as a pore former, aiming to improve the membrane surface porosity and hydrophilicity. Modified membranes were characterized to observe the influence of varying the TGF content on their hydrophilicity, porosity, morphological structure, and composition, as well as their entire performance. The results disclosed that porosity and hydrophilicity of the modified membrane prepared using 4 wt.% TGF content recorded an enhancement by 24% and 38%, respectively. Herein, the lower contact angle was mainly a reflection of the improved porosity, but not of the hydrophilic nature of water-soluble TGF. Furthermore, upon increasing the TGF content in the polymeric matrix, a more porous structure with longer finger-like micropores was formed. Moreover, a sponge-like layer clearly appeared near the bottom surface. Nevertheless, at optimum TGF content (4%), a clear enhancement in the water flux and BSA retention was witnessed by values of 298 LMH and 97%, respectively. These results demonstrate that the obtained permeation and separation behavior of the PES/TGF membrane could stand as a promising choice for water and wastewater treatment applications.

Modification of ultrafiltration membrane with antibacterial agent intercalated layered nanosheets: Toward superior antibiofouling performance for water treatment

Membrane fouling, especially biofouling induced by biofilm formation on membranes, can result in frequent cleaning or even replacement of membranes. Fabrication of membrane with excellent antibiofouling property is quite attractive due to its effectiveness and low-impact on the operation of membrane-based process. Herein, a cationic antibacterial agent, quaternary ammonium compound (QAC), was intercalated into the interlayer spaces of the MgAl layered double hydroxide (QAC/LDH) by self-assembly. The QAC/LDH composite was incorporated into polyethersulfone (PES) ultrafiltration (UF) membrane (PES-QLDH). The QAC/LDH enhanced the hydrophilicity, water flux, and resistance to organic fouling for the PES-QLDH membrane. The PES-QLDH membrane exhibited superior antibiofouling performance than the control PES membrane, with deposition of a thinner biofilm layer consisted of almost dead cells. The superior antibacterial activity inhibits the adhesion and growth of bacteria on the membrane surface, effectively retarding the formation of biofilms. Importantly, the synergistic effect of QAC and LDH in the PES-QLDH membrane resulted in a high biocidal activity based on both direct and indirect killing mechanisms. The PES-QLDH membrane maintained a stable and high antibacterial activity after several fouling-cleaning cycles. These results imply that the PES-QLDH membrane provides an effective and promising strategy for its long-term application in wastewater treatment.

Ultrafiltration Process Yield Study on Aqueous Solution of Total Ginsenosides

Ultrafiltration membrane separation is a technology used to separate large and small molecules in solution by using the principle of membrane screening. This technology can retain the effective components of traditional Chinese medicine extract, remove macromolecular impurities and endotoxin, and meet the requirements of high quality, high efficiency, and low pollution in the modern production of traditional Chinese medicine. The study investigated the impact of 100 KDa molecular weight prepared from different ultrafiltration membrane on the ginsenosides ingredient composition of ginsenosides Rg1, ginsenoside Re, ginsenoside Rf, ginsenoside Rb1, ginsenoside Rg2, ginsenoside Rc, ginsenoside Rb2, ginsenoside Rb3, ginsenoside Rd and ginsenoside Rg3. Changes in retention rates were compared by the component changes in high-performance liquid chromatography in the volume concentrates, par volume of water constant volume diafiltration and 50% ethanol constant volume diafiltration ultrafiltration process. The results demonstrate that the 100 K cellulose ultrafiltration membrane was used for ginsenosides ultrafiltration. The yield and retention were superior to those of the polyethersulfone ultrafiltration membrane with the same molecular weight cutoffs.

Application of Response Surface Methodology for Optimization and Separation of Free Glycerol, Diglyceroids and Triglycerides from Biodiesel Using PES Ultrafiltration Membrane

The available natural energy sources are inadequate to satisfy the demands of an increasing population and control environmental pollution. It is critical to prioritise alternative energy sources like biodiesel. Biodiesel is an eco-sustainable and renewable energy source. But impurities present in biodiesel causes problems in internal combustion engine and emission of hazards gases after burning, it must be separated in accordance with international standards. Conventional techniques are insufficient for separating impurities from biodiesel. Membrane separation technology has been found to be a cost-effective and environmentally friendly technique for biodiesel separation. In this study, 10 KDa polyethersulfone ultrafiltration membranes were used to separate impurities from biodiesel such as free glycerol, diglyceroids, and triglycerides. The response surface was used to analyse the influence of operating variables such as temperature, transmembrane pressure, and water addition on impurity separation as well as optimization. The impurities were separated according to international standards, and at optimal conditions, 96.45 % free glycerol, 54.37 % diglyceroids, and 61.66 % triglycerides were removed at 60°C, 0.3 wt% water addition, and 2.6 bars transmembrane pressure.

Prepare of sunlight response NH2-MIL-125/PES composites ultrafiltration membrane for flux incrementation and fouling alleviation

In this paper, a novel hydrophilic composite polyethersulfone (PES) ultrafiltration membrane was prepared by blending sunlight response photocatalyst NH2-MIL-125 via the phase inversion method. The physical-chemistry performance of membrane was carried out by XRD, FTIR, UV-VIS/DRS, contact angle, and cross-section SEM images. The separation ability, anti-fouling ability, and self-cleaning efficiency of ultrafiltration membrane were analyzed by ultrafiltration experiment using the congo red solution. The results indicate that fouling resistance and the flux recovery ratio of ultrafiltration membrane is significantly improved, and it has higher solar response energy. There was no significant change in the rejection ratio of pollutants before and after illumination. For the pristine PES membrane and the 0.5% NH2-MIL-125/PES nanocomposite membrane, the water flux recovery ratio (FRR) could increase from 37.84% to 77.09%, and the Rr could increase from 22.22% to 44.09%, and the Rir could decrease from 67.11% to 47.09%. In a conclusion, the addition of NH2-MIL-125 at a low concentration could result in membranes with more pure water flux, better rejection, and good fouling resistance compared to the unfilled PES membrane.

Functional charcoal based nanomaterial with excellent colloidal property for fabrication of polyethersulfone ultrafiltration membrane with improved flux and fouling resistance

In this work, charcoal based nanomaterial (charcoal-NM) with two-dimensional structure, high oxygen and nitrogen content (functional groups) and excellent colloidal dispersion property was synthesized and used to prepare ultrafiltration polyethersulfone (PES) mixed-matrix membranes (MMMs), via phase-inversion method. The charcoal-NM can be dispersed in water and organic solvents without sonication and its colloidal dispersion shows high stability for a long time. The influences of the charcoal-NM on morphology, antifouling behavior, pure water flux (PWF) and hydrophilicity of the fabricated MMMs were studied, and the optimum membrane was selected. Antifouling investigations were done by Bovine serum albumin (BSA) as fouling agent. It was found that incorporation of the charcoal-NM into the PES matrix causes formation of channels with vertical alignment in the membrane structure and enhancing the membrane hydrophilicity and therefore leads to improved flux recovery ratio (FRR), PWF and antifouling properties of the MMMs. The fabricated MMM with 0.6 wt% charcoal-NM was selected as the optimal membrane (with PWF of 410.16 LMH, FRR of 95.43% and BSA rejection of 95.89%). This work showed that the charcoal-NM with low cost and excellent dispersion property can be used as an effective nanofiller for MMMs preparation for environmental applications.

Sustainable Modification of Polyethersulfone Membrane with Poly(Maleic Anhydride-Co-Glycerol) as Novel Copolymer

This work presented an endeavour to fabricate sustainable and eco-friendly polyethersulfone (PES) ultrafiltration membranes. A novel and graft copolymer (Poly(Maleic Anhydride-Co-Glycerol)) (PMG) have been synthesized via a facile and rapid route to impart their hydrophilic features onto the final PES membrane. A series of characterization tools, for both nanoadditives and nanocomposite membranes, have been harnessed to confirm their successful fabrication processes. These include Fourier Transform Infrared Spectroscopy (FT-IR), scanning electron microscopy (SEM), Atomic Force Microscopy (AFM), and contact angle measurements (CA). Results disclosed the successful synthesis of PMG nanoparticles that manifested a smooth homogenous surface with an average molecular size of 88.07 nm. The nanocomposite membrane structure has witnessed a gradual development upon each increment in the nanoparticle content ratio along with relatively thicker pore walls. The size and shape of figure-like micropores exhibited critical visible structural changes following the nanoadditive incorporation into the PES polymeric matrix. For the nanocomposite membrane, the SEM imaging indicated that a thicker active layer and less finger-like micropores were formed at higher PMG NP content within the membrane matrix. Hydrophilicity measurements disclosed a reversible correlation with the NP content where the CA angle value was at a minimum at the higher PMG loading content. Compared to the pristine membrane, a considerable enhancement in the performance of the modified membranes was witnessed. The membrane prepared using 2.5 g PMGNPs showcased six times higher pure water flux than neat PES membrane and maintained the highest retention (98%) against BSA protein solution. Additionally, the nanocomposite revealed promising antifouling and self-cleaning characteristics.

Modified Polyethersulfone Ultrafiltration Membrane for Enhanced Antifouling Capacity and Dye Catalytic Degradation Efficiency

Catalytic membranes, as a combination of heterogeneous advanced oxidation and membrane technology reaction systems, have important application prospects in the treatment of dyes and other organics. In practical applications, it is still challenging to construct catalytic membranes with excellent removal efficiency and fouling mitigation. Herein, molybdenum disulfide-iron oxyhydroxide (MoS2-FeOOH) was fabricated using iron oxide and MoS2 nanoflakes, which were synthesized by the hydrothermal method. Furthermore, by changing the concentration of MoS2-FeOOH, the MoS2-FeOOH/polyethersulfone (PES) composite ultrafiltration membrane was obtained with improved hydrophilicity, permeability, and antifouling capacity. The pure water flux of the composite membrane reached 385.3 L/(m2·h), which was 1.7 times that of the blank PES membrane. Compared with the blank membrane, with the increase of MoS2-FeOOH content, the MoS2-FeOOH/PES composite membranes had better adsorption capacity and catalytic performance, and the membrane with 3.0% MoS2-FeOOH content (M4) could be achieved at a 60.2% methylene blue (MB) degradation rate. In addition, the membrane flux recovery ratio (FRR) of the composite membrane also increased from 25.6% of blank PES membrane (M0) to more than 70% after two cycles of bovine serum albumin (BSA) filtration and hydraulic cleaning. The membrane with 2.25% MoS2-FeOOH content (M3) had the best antifouling performance, with the largest FRR and the smallest irreversible ratio (Rir). Catalytic self-cleaning of the composite membrane M3 recovered 95% of the initial flux with 0.1 mol/L H2O2 cleaning. The MoS2-FeOOH/PES composite membranes with the functions of excellent rejection and antifouling capacity have a good prospect in the treatment of printing and dyeing wastewater composed of soluble dyes.

In-situ healing of damaged polyethersulfone ultrafiltration membranes with microgels

The damage of water treatment membranes under operation is a thorny problem, resulting in a great reduction of separation performance and compromised water quality. Here, we shall report a facile method for in-situ reparation of damaged membranes by using damaged polyethersulfone (PES) ultrafiltration (UF) flat membranes as model systems and quaternized crosslinked microgels coded as PNI6 microgels as the healing materials. The PNI6 microgels were synthesized via surfactant free emulsion polymerization of N-isopropylacrylamide (NIPAM) and 1-vinylimidazole (VIM) in the presence of 1,6-dibromohexane (BrCH). The obtained PNI6 microgel suspension was used as the feeding liquid to successfully heal the wound of damaged PES UF flat membranes by filtration deposition. An absorbed microgel layer was formed on the wound site of membranes and hence healed the wound. The rejection performances of microgel-healed PES UF membranes were recovered to the original level of pristine membranes although the water flux decreased from 588.6 L/(m2 h bar) for the pristine membrane to 228.8 L/(m2 h bar) for the healed membranes. It was also demonstrated that the microgel-healed PES UF membranes were chemically stable in both strong acidic and basic conditions and durable in a wide temperature range from 25 to 70 °C with a long-term stability.

Hydrophilized Ultrafiltration Membranes Synthesized from Acrylic Acid Grafted Polyethersulfone for Downstream Processing of Therapeutic Insulin and Cobalamin

The present study focuses on synthesis of novel high-performance acrylic acid (AA) grafted polyethersulfone (PES) ultrafiltration (UF) membranes for purification of small therapeutic biomolecules such as urea, insulin, and cobalamin. The membranes were indigenously synthesized by adding polyethylene glycol (PEG) of 6 kDa M.Wt. as a pore former and subsequent grafting of AA using 2 to 6 wt.% concentrations under UV-induced photo grafting. Scanning electron microscopy reveals that the PEG additive profoundly influences the pore density on the membrane surface. FTIR spectra confirm the graft polymerization of AA with the PES substrate. Separation performance of the grafted membranes was evaluated to establish the trade-off between the degree of grafting and MWCO. From the experimental results, the pure water flux (PWF) of 6% grafted PES membrane was enhanced from 8.5 (PES [0] [6]) to 18.20 l m−2 h−1 (PES [6 +] [6]) in the presence of PEG pore former, respectively. The grafting concentration window of 2–6% resulted in selective membranes to altogether remove uremic toxins into the permeate with retention of high molecular size proteins. Hence, 5 and 6 wt.% AA grafted membranes exhibited > 90% rejection for insulin and cobalamin biomolecules along with 24.5 and 23.8 l m−2 h−1 bar−1 permeability towards urea, respectively. The process results correlate well with the MWCO values of membranes ranging from 1 to 10 kDa. This work provides the efficacy of these grafted membranes for potential application in the downstream processing of therapeutic biomolecules such as insulin and cobalamin.

Influence of Draw Ratio and Take-Up Velocity on Properties of Ultrafiltration Hollow Fiber Membranes from Polyethersulfone

This study aimed to reveal the influence of the draw ratio and take-up speed on the pore size distribution and morphology of the hollow fiber ultrafiltration membrane selective layer. To this end, spinnerets with ring ducts of 1.8 and 1.3 mm were employed, whereas the external diameter of the obtained fiber was kept equal. Atomic force microscopy and scanning electron microscopy were employed to study the morphology of the selective layer. Liquid–liquid displacement porosimetry was used to determine the limiting pore size distribution. The produced polyethersulfone ultrafiltration membranes had a robust, sponge-like porous structure, permeance 1000 L/(m2·h·bar), smooth selective layer, and mean pore size 25 nm. It was found that limiting pore sizes are affected more by the change in the take-up speed, whereas the surface pore sizes, roughness, and morphology are controlled by the draw ratio. It was shown that excessive draw causes the selective layer stretching and crop-up of the porous sublayer. Consequently, the diameters of the spinneret ring duct and the bore needle should match the hollow fiber outer and lumen diameters, respectively.

Polyethersulfone ultrafiltration membranes incorporated with CeO2/GO nanocomposite for enhanced fouling resistance and dye separation

The hydrophilic CeO2/GO nanocomposite was successfully synthesized and characterized using scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and Brunauer-Emmett-Teller (BET) methods. The SEM images of the nanocomposite confirmed meaningful decrease in the diameter of the CeO2 nanoparticles from 90 to about 30–40 nm after loading on the GO nanosheets. The as-synthesized nanocomposite was incorporated by various contents into the matrix of the polyethersulfone (PES) membranes. The changes in the morphology of the blended membranes with introduction of the nanocomposite were analyzed using SEM and atomic force microscopy (AFM) techniques. All the CeO2/GO-modified PES membranes showed higher hydrophilicity, porosity and pure water permeation compared with unmodified one. The pure water flux of the nanocomposite membrane containing 0.2 wt% of the nanocomposite was obtained as 249 L m−2 h−1, which was 152 L m−2 h−1 in the pure PES membrane. The results proved that fouling resistance of the nanocomposite membranes was intensified and increased from 39% for bare PES membrane to 69% for the membrane modified with 0.1 wt% of CeO2/GO nanocomposite. The aqueous solution of Reactive Red 195 (R195), Reactive Red 43 (R43), and Yellow 105 (Y105) organic dyes were applied to evaluate the separation performance of the membranes. The results revealed that membrane modified with 0.5 wt% of CeO2/GO exhibited the removal efficiency of 88%, 93% and 98% for R195, R43 and Y105, respectively. Furthermore, the membranes modified with CeO2/GO showed better dye retention performance compared with membranes modified with CeO2 and GO alone.

A high stability GO nanofiltration membrane preparation by co-deposition and crosslinking polydopamine for rejecting dyes.

In order to improve the stability of nanofiltration membrane in separation and purification, a novel polyelectrolyte multilayer nanofiltration membrane was facilely prepared by co-deposition of polydopamine (PDA) and polyethyleneimine (PEI) on the polyethersulfone (PES) ultrafiltration membrane substrate, followed by immersing graphene oxide (GO) solution, and crosslinking PDA. The modified surfaces were characterized using scanning electron microscopy (SEM) and atomic force microscopy (AFM), water contact angle, their saline flux and ability to reject salt and dye were determined. The results also exhibited salt rejection ability as Na2SO4 > K2SO4 > MgSO4 > NaCl > KCl > MgCl2, suggesting the higher rejection of divalent anion. Also, the retention order of the dye by the GO modified membrane is DY86 > DB19 > AG27 > DY142 > DB56 > AR151 > VB5, indicating that the GO modified membrane has better rejection of negatively charged dyes as well as higher molecular weight dyes. Ethanol and hypochlorite resistance tests under different pH conditions showed the membranes coated GO enhanced stability in regard to salt rejection properties. Significantly, the anti-biological test confirmed the growth rate of microalgae on the GO introduced membrane was decreased greatly due to enhanced stability and lower roughness.

Fabrication of sulfonated polyethersulfone ultrafiltration membranes with an excellent antifouling performance by impregnating with polysulfopropyl acrylate coated ZnO nanoparticles

Sulfonated polyethersulfone/sulfopropyl methacrylate membranes impregnated with the polysulfopropyl acrylate coated ZnO nanoparticles were developed using a non-solvent-induced phase separation recipe. The composite membranes offered much-enhanced hydrophilicity and improved porosity, which are critical for the excellent antifouling performance and high permeate flux. By adding polysulfopropyl acrylate modified ZnO, it achieved the maximum water flux of 420 Lm−2h−1 while maintained the natural organic matter rejection rate of 99% with an excellent flux recovery ratio up to 99% in the antifouling measurement. The results display that the impregnation of ZnO nanoparticles in the sulfonated polyethersulfone membrane can effectively increase the surface hydrophilicity which is essential for reducing the irreversible fouling with improved long-term performance and excellent recyclability.

Properties of Polyethersulfone Ultrafiltration Membrane by Incorporating Ionic Liquid for Humic Acid Removal

The present study was conducted to investigate the properties of fabricated polythersulfone ultrafiltration membrane by incorporating ionic liquid (IL) (Aliquat 336) in the casting solution towards HA removal. IL namely Aliquat 336 is used with varied composition of polyethersulfone (PES) as polymer and and Dimethyl acetamide (DMAC) as a solvent. All the fabricated membranes were characterized by Fourier transform infrared spectroscopy (FTIR), Differential scanning calorimetry (DSC), ganiometer and Thermogravimetric analysis (TGA) analysis. The fabricated membranes were also analyzed through its performance based on water flux, HA flux and HA rejection. The experimental results show that the incorporation of ionic liquid in different composition of polymer resulted in different characteristic of membrane and provided in improvement of HA removal. The P4 membrane gave the best performance with the water flux of 373.25 L/m2.h, the HA flux of 262.68 L/m2.h and the highest removal of HA up to 90%.

Hydrophilic PAA-g-MWCNT/TiO2@PES nano-matrix composite membranes: Anti-fouling, antibacterial and photocatalytic

The synthesis of composite nano-matrix membranes from a variety of nanoscale materials will impair the comprehensive properties of the materials. Therefore, it is not easy to prepare multifunctional nano-matrix membranes with excellent performance. Carbon nanotubes (CNTs) have superiority in absorption of impurities and contaminants in aqueous solution. Therefore, Polyethersulfone (PES) ultrafiltration membrane modified by CNTs and PAA-g-MWCNT/TiO2 (AMT) organic-inorganic hybrid particles is synthesized. And a new nano-matrix composite membrane PAA-g-MWCNT/TiO2@PES (AMTP) is prepared after the combination of the two particles, which endows the new composite membrane with three major effects of fouling resistance, photocatalysis and antibacterial properties. When the amount of AMT was 1 wt%, AMTP had the highest anti-pollution rate (31.21%); the best flux recovery rate (85.76%) and the degradation efficiency of MB and MO reached 90.03%, 62.36% within 2 h; the antibacterial rate was 98.12 %. When the dosage was 2 wt%, the antibacterial rate of AMTP reached 100 %. AMTP nano-matrix composite membranes have considerable adaptability and practicability of a wide application in the wastewater recovery and recycling.

Boosting permeation and separation characteristics of polyethersulfone ultrafiltration membranes by structure modification via dual-PVP pore formers

Asymmetric polyethersulfone (PES) membranes were fabricated from the PES/γ-butyrolactone (GBL)/polyvinylpyrrolidone (PVP) system using non-solvent induced phase separation (NIPS) process. Two types of PVP with different molecular weights (PVP–K30 and PVP-K15) were added as dual pore-forming agents in the dope solution to modify the morphological, physical, permeation, and separation properties of the membranes. Our results demonstrate that high concentration of PVP-K30 in the dope favors the formation of a top skin layer and macrovoids, whereas the PVP-K15 can open the pores on the top surface, shrink the macrovoids, and transform the bi-continuous porous structure toward cellular pores. In the optimal composition of PVP additives (i.e. 8 wt% PVP-K30 and 5 wt% PVP-K15 in this work), the resulted PES membrane exhibits a water flux of 563 L m−2h−1 and a remarkable rejection coefficient over 99% for blue dextran solution, showing a promising potential in ultrafiltration applications.