Highly efficient monovalent ion transport enabled by ionic crosslinking-induced nanochannels

Charge-governed ion transport is of significant importance to industrial development, and advanced membrane materials with fast and selective ionic transport are essential components. In cell membranes, ionic transport is mainly determined by the charge-governed protein channels, representing an architecture with functional differentiation. Inspired by this, a novel class of membranes was developed by ionically crosslinking sulfonated (poly[ether ether ketone]) and quaternized poly(2,6-dimethyl-1,4-phenylene oxide) to construct the cationic conductive biomimetic nanochannels. Ionic crosslinking was tailored to realize nanophase separation and efficient ion transport mainly based on surface chemistry without altering the scaffold feature of polymeric pore channels. The best-performing ionic crosslinking membrane exhibited a high ionic permeation (2.23 mol·m⁻²·h⁻¹ for K⁺) and high cationic selectivity (7.91 for K⁺/Mg²⁺), which were comparable with the commercial monovalent cation permselective CIMS membrane, owing to the negligent surface resistance toward monovalent cations but strong positively charged repulsion against divalent cations.     

One-step preparation of asymmetric ceramic membranes based on sea urchin-like mullite whisker skeletons and their oil-water separation properties

In this work, novel sandwich-type asymmetric ceramic microfiltration membranes with a sea urchin-like mullite whisker skeleton were prepared one step. Their structural properties and oil-water separation performance were investigated. The results show that after sintering at 1400 °C, the prepared membrane possesses good hydrophilic, underwater oleophobic, and anti-fouling properties. During the continuous separation of a 300 mg/L oil-in-water emulsion, a maximum stable flux of 267 L·m⁻²·h⁻¹ was achieved without membrane cleaning. After chemical cleaning and simple physical cleaning, the membranes recovered to a steady flux of 397 L·m⁻²·h⁻¹ and 305 L·m⁻²·h⁻¹, respectively, and maintained a 95% oil rejection. The good underwater oleophobicity and selective permeability brought about by the flat-lying whiskers on the top surface, coupled with the efficient water channels between the sea urchin-like structures inside the membrane, are considered to be the main reasons for its improved separation characteristics over conventional low-cost ceramic membranes.     

Carboxylated PIM-1 incorporating sulfonated graphene oxide effectively improves the ion transport properties of the membrane

This study explores the ion transport properties of self-microporous polymers by introducing a novel combination of carboxylated PIM-1 with sulfonated graphene oxide (SGO) to fabricate membranes. The resulting membranes exhibit enhanced structural stability, hydrophilicity, and ion exchange capacity (IEC) compared with the original carboxylated PIM-1 (CPIM-1), while preserving the subnanoporous structure. However, it was observed that excessive SGO loading leads to a detrimental “blocking effect” that compromises various membrane properties. Through electrically driven ion transport tests in a 0.01 M NaCl solution, it is demonstrated that a moderate amount of SGO effectively enhances membrane conductivity from 46.96 μS m⁻¹ (for carboxylated PIM-1 membranes without SGO) to 56.55 μS m⁻¹. Additionally, the membranes exhibit selective sieving of cations and anions. The presence of small-sized ion channels and the electrostatic repulsion generated by the abundant carboxyl and sulfonic acid groups significantly hinder Cl⁻ transport. Consequently, the Na⁺/Cl⁻ migration ratio (t₊/t₋) reaches 98 at a concentration ratio of 10:1 on both sides of the membrane, surpassing the value of 3.74 observed for the pure CPIM-1 membrane. This investigation provides valuable insights for the practical application of easily prepared, processable, and cost-effective hydrophilic self-contained microporous polymer membranes in ion transport applications.     

Green and feasible fabrication of loose nanofiltration membrane with high efficiency for fractionation of dye/NaCl mixture by taking advantage of membrane fouling

Loose nanofiltration membrane emerges as required recently, since it is hard for conventional nanofiltration membrane to fractionate mixture of dyes and salts in textile wastewater treatment. However, the polymeric membranes unavoidably suffer from membrane fouling, which was caused by the adsorption of organic pollutants (like dyes). Normally, the dye fouling layer will shrink membrane pore size, thus resulting in flux decline and rejection increase. It is thought that membrane fouling may be a double-edged sword and can be an advantage if properly utilized. Thereby, loose nanofiltration membranes were constructed here by a green yet effective method to fractionate dyes/salt mixture by taking advantage of membrane fouling without using poisonous ingredients. A commercially available polyacrylonitrile (PAN) ultrafiltration membrane with high permeability was chosen as the substrate, and dyes were used to contaminate PAN substrate and formed a stable barrier layer when adsorption of dyes reached dynamic equilibrium. The resultant PAN-direct red 80 (DR80) composite membranes displayed superior permeability (~128.4 L m⁻² h⁻¹) and high rejection (~99.9%) to DR80 solutions at 0.4 MPa. Moreover, PAN-DR80 membranes allowed fast fractionation of dyes/sodium chloride (NaCl) mixture, which maintained a negligible dye loss and a low NaCl rejection (~12.4%) with high flux of 113.6 L m⁻² h⁻¹ at 0.4 MPa. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47438.     

Increasing the performance of asymmetric pervaporation membranes for the separation of methanol/methyl-tert-butyl ether mixtures by the introduction of sulfonated polyimide into the poly(amide-imide) matrix

A series of novel asymmetric membranes from polymer composites of poly(amide-imide) with various content of sulfonated polyimide (1–6 wt%) was obtained through the nonsolvent-induced phase separation process. Selective transport properties of the obtained materials were investigated in terms of pervaporation separation of methanol/methyl-tert-butyl ether mixtures at different temperatures. The introduction of the sulfonated polyimide to the poly(amide-imide) matrix leads to a significant increase in membrane flux and an overall decrease in the process selectivity. Composite membranes having 1 wt% sulfonated polyimide in the matrix showed increased values of membrane flux (0.960 kg m⁻² h⁻¹ in comparison with 0.682 kg m⁻² h⁻¹ for unmodified membranes at 40°C, 10 wt% methanol), while having similar selectivity values (79.2 wt% methanol in permeate in comparison with 82 wt% for unmodified membranes at 40°C, 10 wt% methanol). Modified membrane showed the highest separation factor of 147 while separating methanol from its 3 wt% mixture with methyl-tert butyl ether at 52°C with the overall flux of 1.01 kg m⁻² h⁻¹. A semiempirical mathematical model was developed and applied to test the efficiency of obtained membranes in the hybrid process of methanol/methyl-tert-butyl ether mixtures separation.     

Pervaporation separation of benzene/cyclohexane through AAOM-ionic liquids/polyurethane membranes

Supported ionic liquids/polyurethane (PU) membranes were prepared by immobilizing ionic liquids on a porous anodic aluminum oxide membrane (AAOM) support that was coated on one side with polyurethane (PU). The microstructure of all membranes was characterized using scanning electron microscopy (SEM). The pervaporation separation performance of the supported ionic liquids/polyurethane membranes was investigated for benzene/cyclohexane (Bz/Cy) mixtures. The SEM results demonstrated that the porous surface of the AAOM support was sealed by the dense polyurethane membrane and the pores of the AAOM support were impregnate with ionic liquids. The ionic liquids filling in the AAOM support enhanced the separation selectivity of Bz/Cy. The separation factor of Bz to Cy increased from 5 to 34.4 and the largest PSI of AAOM-[C₄mim]PF₆/PU membrane reached 452.54 g m⁻² h⁻¹ at 55 °C for a 50 wt.% Bz/Cy mixture. Because the polyurethane prevented the leakage of ionic liquids filled in the AAOM support, the supported ionic liquids/polyurethane membranes exhibited excellent stability.     

In vitro cadmium removal from human serum by Cibacron Blue F3GA–thionein‐complex conjugated affinity membranes

A new membrane affinity biosorbent carrying thionein has been developed for selective removal of cadmium ions from human serum. Microporous poly(2‐hydroxyethyl methacrylate) (pHEMA) membranes were prepared by photopolymerization of HEMA. The pseudo dye ligand Cibacron Blue F3GA (CB) was covalently immobilized on the pHEMA membranes. Then, the cysteine‐rich metallopeptide thionein was conjugated onto the CB‐immobilized membrane. The maximum amounts of CB immobilized and thionein conjugated on the membranes were 1.07 µmol cm⁻² and 0.92 µmol cm⁻², respectively. The hydrophilic pHEMA membrane had a swelling ratio of 58% (w/w) with a contact angle of 45.8 °. CB‐immobilized and CB‐immobilized–thionein‐conjugated membranes were used in the Cd(II) removal studies. Cd(II) ion adsorption appeared to reach equilibrium within 30 min and to follow a typical Langmuir adsorption isotherm. The maximum capacity (q _m) of the CB‐immobilized membranes was 0.203 (µmol Cd(II)) cm⁻² membrane and increased to 1.48 (µmol Cd(II)) cm⁻² upon CB–thionein‐complex conjugation. The pHEMA membranes retained their cadmium adsorption capacity even after 10 cycles of repeated use. © 2000 Society of Chemical Industry     

Development of a high-performance polysulfone hybrid ultrafiltration membrane using hydrophilic polymer-functionalized mesoporous SBA − 15 as filler

A novel polysulfone hybrid ultrafiltration membrane was developed by blending hydrophilic poly[poly(ethylene glycol) methyl ether methacrylate] [P(PEGMA)] grafted mesoporous SBA-15 [SBA-g-P(PEGMA)] as filler. The hydrophilic SBA-g-P(PEGMA) fillers were synthesized via surface-initiated atom transfer radical polymerization. The effects of the SBA-g-P(PEGMA) fillers on the prepared hybrid membranes were systematically investigated. Compared with pristine SBA-15 fillers, SBA-g-P(PEGMA) fillers contributed to higher hydrophilicity and a more developed pore structure in the hybrid membranes. Specifically, SBA-15 grafted with a moderate P(PEGMA) molecular weight could better preserve the valid open-ended filler pore structure in the membrane matrix, thus facilitating membrane permeability. The pure water flux of the as-prepared polysulfone (PSF)/SBA-g-P(PEGMA) membrane was three times that of the PSF/SBA-15 membrane (271.7 L m⁻² h⁻¹ vs. 88.2 L m⁻² h⁻¹) with similar membrane selectivity. Moreover, the PSF/SBA-g-P(PEGMA) membranes showed improved antifouling property. This work paves the way for developing high-performance hybrid membranes by blending of hydrophilic polymer-functionalized mesoporous fillers in the future. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47353.     

Enhanced the antifouling and antibacterial performance of PVC/ZnO-CMC nanoparticles ultrafiltration membrane

Inorganic nanoparticles (NPs) have been employed in modification for polyvinyl chloride (PVC) membrane intrinsic hydrophobicity. Carboxymethyl chitosan (CMC), a natural organic matter, was used to relieve the agglomeration of zinc oxide (ZnO) NPs in the membrane matrix. In this paper, ZnO-CMC NPs were successfully prepared via co-precipitation approach, blended with PVC membranes, and the effect of ZnO-CMC NPs for the membrane properties was studied. The SEM and EDX confirmed excellent dispersion of ZnO-CMC NPs on the membrane surface. The enhanced hydrophilicity, porosity and inter-connected finger-like strcture of modified membranes confirmed by water contact angle and SEM. In addition, pure water flux of PVC/ZnO-CMC composite membrane was 107.36 L m⁻² h⁻¹ (PVC/ZnO-CMC (0.25 wt%)), which was higher than that of neat PVC membrane (83.11 L m⁻² h⁻¹). Importantly, the modified membranes exhibits lower static BSA adsorbtion because of the improved hydrophilicity, and a higher flux recovery rate (>90%) after three sequential filtration cycles. The antibacterial behavior of PVC/ZnO-CMC membrane was tested simply using Escherichia coli, and the results indicated that all composite membranes possess excellent antibacterial properties. Our work presents PVC/ZnO-CMC NPs composite membrane a promising future in wastewater treatment and antibacterial application.     

Nanosheet-templated graphene oxide membranes for fast molecule separation

Intercalated laminar membrane with controllable interlayer spacing (d-spacing) is one of the most effective membranes for fast molecule separation. In this work, we demonstrate a versatile strategy to create nanosheet-templated water channels in laminar graphene oxide (GO) membranes. The 1.2 nm-thick nickel hydroxide nanosheets as sacrificed intercalators provide a chance to control the d-spacing. The resultant membranes have controllable channels and exhibit over six times higher water permeance than the unintercalated membrane. The 880 nm-thick nanosheet-templated GO (NST-GO) membrane has accurate d-spacing of about 1.14 nm and shows high water permeance of 120.3 L m⁻² h⁻¹ bar⁻¹ and good molecule separation property, reflecting in high rejection for larger dyes (90.1% for erythrosine B [EB]), while low rejection for smaller dyes (58.3% for methylene blue [MB]). Furthermore, this strategy of intercalating and sacrificing nanosheets has higher potential than traditional intercalation in controlling d-spacing of laminar membranes.     

Fabrication and characterization of silane-functionalized Na-bentonite polysulfone/polyethylenimine nanocomposite membranes for dye removal

In this study, tetraethoxysilane (TEOS)-functionalized Na-bentonite incorporated into polysulfone/polyethylenimine (PSF/PEI) membranes were fabricated by phase inversion method for the efficient removal of methylene blue dye. For the preparation of PSF/PEI nanocomposite membranes, silane-functionalized Na-bentonite and pure Na-bentonite were used at three different concentrations (0.5, 1, and 2 wt%). The prepared membranes were characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, atomic force microscopy, porosity, hydrophilicity, and water permeability measurements. Antifouling behaviors and methylene blue dye rejections of the PSF/PEI nanocomposite membranes were also tested. The obtained results showed that the addition of pure Na-bentonite and silane-functionalized Na-bentonite both increased the water permeability of the membranes. The PSF/PEI membrane containing 2 wt% silane-functionalized Na-bentonite showed the highest water flux of 105 L m⁻² h⁻¹, while the lowest water flux of 1.2 L m⁻² h⁻¹ was recorded for pure PSF membrane. Filtration results demonstrated that the antifouling capacity was significantly increased due to the negatively charged surface of the newly generated silane-functionalized Na-bentonite PSF/PEI membranes. In summary, TEOS-functionalized Na-bentonite can be used to fabricate PSF/PEI nanocomposite membranes with effective filtration ability, antifouling capacity with lower decay ratio, higher flux recovery ratio, and 99% methylene blue dye removal performance.     

Synthesis and characterization of PES/PSF/PEG by immersion precipitation for Mediterranean seawater desalination by FO membrane

In the present study, a simple, inexpensive, nontoxic, and environmentally friendly polyethylene glycol (PEG) polymer was used to enhance the hydrophilicity of the forward osmosis (FO) membrane using various PEG concentrations as a pore forming agent in the casting solution of polyethersulfone/polysulfone (PES/PSF) blend membranes. A nonwoven PES/PSF FO blend membrane was fabricated via the immersion precipitation phase inversion technique. The membrane dope solution was cast on polyethylene terephthalate (PET) nonwoven fabric. The results revealed that PEG is a pore forming agent and that adding PEG promotes membrane hydrophilicity. The membrane with 1 wt% PEG (PEG1) had about 27% lower contact angle than the pristine blend membrane. The PEG1 membrane has less tortuosity (which reduces from 3.4–2.73), resulting in a smaller structure parameter (S value) of 277 μm, due to the presence of open pores on the bottom surface structure, which results in diminished ICP. Using 1 M NaCl as the draw solution and distilled water as the feed solution, the PEG1 membrane exhibited higher water flux (136 L m⁻² h⁻¹) and lower reverse salt flux (1.94 g m⁻² h⁻¹). Also, the selectivity of the membrane, specific reverse salt flux, (J_s/J_w) showed lower values (0.014 g/L). Actually, the PEG1 membrane has a 34.6% higher water flux than the commercial nonwoven-cellulose triacetate (NW-CTA) membrane. By means of varied concentrations of NaCl salt solution (0.6, 1, 1.5, and 2 M), the membrane with 1 wt% PEG showed improved FO separation performance with permeate water fluxes of 108, 136, 142, and 163 L m⁻² h⁻¹. In this work, we extend a promising gate for designing fast water flux PES/PSF/PEG FO blend membranes for water desalination.     

Enhanced glycerol dehydration of pervaporation cross-linked PVA membranes modified by VUV/UV-C treatments

The high glycerol miscibility in water needs more efficient processes to decrease the cost of dehydration. Water stable poly(vinyl alcohol) based membranes cross-linked with 15% w/w of maleic acid were used for dehydrating glycerol-water mixtures using pervaporation (PV). The membranes were characterized using water contact angle, profilometry, Fourier transformed infrared spectroscopy-attenuated total reflectance, x-ray photoelectron spectroscopy, water stability, swelling tests, and PV. Membranes were treated using dry methods with vacuum ultraviolet (VUV; 162 nm) or ultraviolet (UV)-C (254 nm) radiation and exposed to O₂ or acrylic acid vapors, respectively. The VUV and UV-C treatments improve PV performances, increasing the water separation selectivity more than 4 and 8.5 times, respectively. UV-C treatments exhibit a water flux (kg m⁻² h⁻¹), selectivity and PSI (kg m⁻² h⁻¹) of 0.3, 250, and 87.4 respectively. Highly hydrophilic functional groups grafted onto the surface of the membranes after irradiation favor the selective transfer of water through the membrane. Overall, the VUV or UV-C membrane treatments show great PV prospect in glycerol dehydration.     

Perforative pore formation on nanoplates for 2D porous MXene membranes via H2O2 mild etching

MXene (Ti₃C₂T_x) is a novel, two-dimensional (2D) layered material that is atomically thin, exhibits good mechanical strength, and is ideal for fabricating efficient membranes for molecular separation. However, the applications of MXene membranes are limited by their low water permeability owing to narrow channels and high tortuosity. A novel strategy for introducing artificial pores on the surface of MXene nanosheets via gentle in situ chemical etching with hydrogen peroxide (H₂O₂) to prepare porous MXene nanosheets (PMS) is reported herein. This greatly increases the water permeability of MXene membranes while retaining the high rejection of small-molecule dyes. Permeable pores generated on MXene nanosheets transform the transport model of water molecules in the membrane from typical horizontal transport pathways dominated by interlayer channels to longitudinal–lateral three-dimensional transport pathways, affording increased water molecule transport channels and reduced transport distance. Based on different etching conditions, the obtained membranes exhibit high pure-water permeability ranging from 9.37 to 42.48 L m⁻² h⁻¹ bar⁻¹. Moreover, mild etching maintains the 2D structure of the membrane and retains a nearly complete rejection of congo red dye. This study provides a novel and effective strategy for preparing high-performance porous laminar MXene membranes for dye-separation applications.     

The role of silver nanoparticles on mixed matrix Ag/cellulose acetate asymmetric membranes

Mixed matrix asymmetric membranes were prepared by the addition of silver nanoparticles to cellulose acetate/acetone/formamide casting solutions with ratios acetone/formamide varying from 1.44 to 2.77 to prepare ultrafiltration/nanofiltration membranes covering a wide range of hydraulic permeabilities. Binding of the silver nanoparticles to the polymer matrix is revealed through comparison of the FTIR spectra of the cellulose acetate and the Ag/cellulose acetate membranes. In the later, there is a decrease of the ratio between the bands intensities at 2,000–2,500 cm⁻¹. Membrane surface charge of the mixed matrix membranes varies with the pore size and pH, and when compared with cellulose acetate membranes there is a decrease of the negative surface charge densities. The silver nanoparticles in all mixed matrix membranes results in an enhancement of the hydraulic permeabilities, ranging from 10.8 kg m⁻² h⁻¹ bar⁻¹ to 67.1 kg m⁻² h⁻¹ bar⁻¹. POLYM. COMPOS., 38:32–39, 2017. © 2015 Society of Plastics Engineers     

Fabrication of highly permeable PDMS@ZIF-8/PVDF hollow fiber composite membrane in module for ethanol-water separation

The construction of high-performance MOF-based hollow fiber composite membrane (HFCM) modules is a significant, yet challenging task for the biofuel production industry. In this study, a novel approach was taken to fabricate PDMS@ZIF-8/PVDF HFCMs in modules through a facile ZIF-8 self-crystallization synthesis followed by pressure-assisted PDMS infusion for pervaporation ethanol-water separation. The as-prepared HFCMs exhibited an ultrathin separation layer (thickness, 370 ± 35 nm), which was achieved through precise regulation of the ZIF-8 membrane and defect repair by PDMS infusion. Moreover, the strategy utilized in this study resolved the defect issues arising from MOF agglomeration in conventional composite membranes. Impressively, at the optimal packing density, the prepared membrane demonstrated a remarkable ethanol flux (1.11 kg m⁻² h⁻¹) with an PSI value (26.59 kg m⁻² h⁻¹) and showed promising long-term stability for the pervaporation of 5 wt% ethanol aqueous solution at 40°C.     

Fabrication and performance of reticular ceramic fiber membranes by freeze casting using a gel network

It is of great practical significance to manufacture ceramic membranes with good reusability. We used a macromolecular gel network for in situ enhancement of a reticulated skeleton ceramic (RSC) membrane. The prepared RSC membranes were firstly characterized to determine their physical and chemical properties. The sample calcined at 1400 °C has a porosity of 41.66 %, a pore size of 0.34 μm, a mechanical strength of 4.53 MPa, and a permeability of 63.92 L m⁻¹ h⁻¹ bar⁻¹. This membrane can effectively reduce the content of total organic carbon (TOC) (80 %) and calcium ion (>85 %). In addition, the flux of RSC fouled by alginate, calcium ions, or their mixture is effectively recovered by simple chemical rinsing using sodium hydroxide and ethylenediaminetetraacetic acid.     

Molecule transfer mechanism in two-dimensional heterostructured lamellar membranes: The effects of dissolution and diffusion

Two-dimensional lamellar membranes are promising for efficient molecule transfer, while the underlying transfer mechanism is rarely elucidated. Herein, heterostructured nanosheets are prepared by self-assembling small-sized hydrophilic cyanuric acid melamine and hydrophobic g-C₃N₄ nanosheets. Resultant lamellar membranes show comparable affinity to polar and nonpolar solvents, allowing them to dissolve on membrane surface and diffuse through membrane channels. Results demonstrate that for lamellar membranes with distinct wettability, the permeance difference for polar solvents is originated from dissolution and diffusion processes, while that for nonpolar solvents is stemmed from dissolution process. Accordingly, corresponding equations which are suitable for heterostructured lamellar membranes are established. Importantly, polar solvents are induced to form ordered arrangement in hydrophilic nanodomains and then maintain the ordered state in hydrophobic nanodomains, affording a low-resistance transfer and high acetonitrile permeance of 1025 L m⁻² h⁻¹ bar⁻¹. In contrast, nonpolar solvents with disordered arrangement exhibit lower permeance than that of polar ones.     

Novel polyamide composite membranes for gas separation prepared by interfacial polycondensation

Interfacial polycondensed composite membranes are well known for reverse osmosis. This study describes the preparation of interfacial polymerized composite membranes for gas separation obtained from new polyamides. The polymers were synthesized by derivates of terephthaloylchloride and commercially available multifunctional amines. The membrane polymers consist of linear or crosslinked chains. A high flux of carbon dioxide, 0.3 m³m⁻²h⁻¹bar⁻¹, was observed, combined with a carbon dioxide/nitrogen selectivity up to 30. The permeability to hydrocarbons increased with hydrocarbon vapor concentrations. The synthesis of the thin polyamide layer was transmitted to a continuous production. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 63: 1557–1563, 1997     

A TiO2 modified whisker mullite hollow fiber ceramic membrane for high-efficiency oil/water emulsions separation

Design and preparation of membranes with ultrahigh separation performance and antifouling property for oil-in-water (O/W) emulsions remains challenging. In this study, a high flux mullite/TiO₂ ceramic composite membrane was prepared via multi-precipitation of TiO₂ on a whisker mullite hollow fiber support synthesized by combining phase inversion and high-temperature sintering techniques. The results showed that the generated whisker mullite structure improved the permeation flux, and the micro-nano structured TiO₂ functional layer endowed the membrane surface with superhydrophility and stability. The retention of the optimal composite membrane (M20T13) that was soaked in the titanium solution 20 times for 13 min each time for the O/W emulsions like n-hexane, toluene and engine oil maintained over 98 %, and the flux after 6 h filtration was 668.34 L·m⁻²·h⁻¹, 487.25 L·m⁻²·h⁻¹ and 258.66 L·m⁻²·h⁻¹, respectively, much higher than that of the optimal substrate (F3A1, mass ratio of fly ash: Al₂O₃ = 3:1). Moreover, the flux recovery rate of M20T13 was much higher than that of F3A1 after chemical backwashing. This work manifests great potential in O/W treatment fields.