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Catalytic Pd decorated graphene oxide (Pd/GO) membrane with efficient catalytic activity was developed by in-situ reduction of Pd2+ on GO nanosheets followed by vacuum filtration. A high 4-nitrophenol (4-NP) reduction efficiency was achieved by using the Pd/GO catalytic membrane with layered structure because of evenly distribution of Pd nanoparticles (NPs) in the interlayer space of GO membrane, ensuring sufficient contact between 4-NP molecules and Pd NPs. The apparent kinetic rate constant and turnover frequency (TOF) reached to 138.4 s−1 and 813 h−1 under a continuous-flow system using 4000 mg/L of 4-NP at 20 °C. During a 300 min of continuous-flow catalysis, the 4-NP conversion was kept above 98% at 20 °C. This high catalytic efficiency of the Pd/GO catalytic membrane under high 4-NP concentration and continuous-flow catalysis made it promising and competitive in the application of catalytic membrane for efficient catalytic process. [Display omitted] • 2D catalytic Pd/GO membrane with efficient catalytic activity was developed. • Pd/GO membrane with high tortuosity can reduce 5000 mg/L of 4-NP effectively. • A rate constant of 138.4 s−1 was achieved under a continuous-flow system. • During a 300 min of continuous-flow catalysis, 4-NP conversion was kept above 98%. [ABSTRACT FROM AUTHOR]

Abstract A new mixed protonic-electronic conducting material, Nd 5.5 W 0.35 Mo 0.5 Nb 0.15 O 11.25-δ (NWMN), was developed by Nb-doping to improve the hydrogen permeability of Nd 5.5 W 0.5 Mo 0.5 O 11.25-δ (NWM). The hydrogen permeation properties and stability of the NWMN were investigated in details. An enhanced hydrogen permeation flux through the NWMN membrane was achieved, which was about 2.5 times as high as that through the un-doped NWM membrane at 800 °C due to the increased ambipolar conductivity. Moreover, the phase structures of the NWMN powder and membrane remained unchanged after the treatment in pure CO 2 and H 2 -containing atmospheres, respectively, which reveals excellent stability of the NWMN powder in CO 2 and H 2 -containing atmospheres. The remarkable stability and improved hydrogen permeability make NWMN promising for the application of hydrogen separation. Highlights • A new H 2 permeable material, Nd 5.5 W 0.35 Mo 0.5 Nb 0.15 O 11.25-δ (NWMN), was developed. • Nb-doping is applied to enhance H 2 permeability of Nd 5.5 W 0.5 Mo 0.5 O 11.25-δ (NWM). • H 2 flux through NWMN membrane is ∼2.5 times as high as that through un-doped NWM. • The NWMN membrane shows excellent stability in CO 2 atmosphere. [ABSTRACT FROM AUTHOR]

Catalytic Pt layers are coated on the surface of the mixed proton-electron conductive membranes based on La 5.5 W 0.45 Nb 0.15 Mo 0.4 O 11.25-δ (LWNM) aiming to promote the hydrogen surface exchange, and effect of the Pt layer on the hydrogen permeation flux through the LWNM membrane has been investigated. A hydrogen permeation flux of 0.483 mL/min∙cm 2 is achieved at 1000 °C fed with a mixture of 50% H 2 − 50% He under wet condition with catalytic Pt layers on both sides of the LWNM membrane, which is twice as much as that of the uncoated membrane, indicating that the Pt layers on the membrane surface exhibit obvious positive effect on the hydrogen permeation. The increase of the hydrogen permeation flux is resulted from the enhancement of hydrogen dissociation/combination on the membrane surface by the Pt layer, which promotes the hydrogen surface exchange process. Moreover, it is more effective when the Pt layer is coated on the sweep side, which demonstrates that the hydrogen surface reaction on the sweep side of the membrane plays a predominant role compared with that on the feed side. [ABSTRACT FROM AUTHOR]

Lanthanum tungstates are the kind of attractive mixed proton-electron conductive (MPEC) oxides, which can be used as the hydrogen permeable membrane with almost infinite hydrogen selectivity in dry hydrogen-containing atmosphere theoretically. A series of lanthanum tungstates with different La/W ratios, La 5.3 WO 11.25-δ (LWO53), La 5.4 WO 11.25-δ (LWO54), La 5.5 WO 11.25-δ (LWO55) and La 5.6 WO 11.25-δ (LWO56), were prepared through a solid-state reaction method and the effect of La/W ratio on the membrane structure, stability and hydrogen permeation properties have been investigated. A pure cubic phase can be formed gradually with the increase in calcination temperature for lanthanum tungstates. The phase formation temperature increases with the increase in the La/W ratio, and a higher oxygen absorption capacity can be achieved in lanthanum tungstate with a higher La/W ratio. The hydrogen permeation flux through the lanthanum tungstate membranes increases slightly with an increase in La/W ratio, while the stability decreases. The lanthanum tungstate membrane with a La/W ratio of 5.5 may be a good candidate for hydrogen separation applications because of its favorable balance between stability and hydrogen permeability. [ABSTRACT FROM AUTHOR]

This study investigates the development of membranes for leukocytes depletion from model hydrogel interfaces. We first designed hydrogels from 2-(dimethylamino)ethyl methacrylate (DMAEMA) and poly(ethylene glycol) methyl ether methacrylate (PEGMA) to form poly(DMAEMA- co -PEGMA), and [2-(methacryloyloxy)ethyl]trimethylammonium chloride (TMA) and PEGMA to form poly(TMA- co -PEGMA). After characterizing the actual chemical composition of the hydrogels by XPS, efforts were made on studying the effect of the nature and content of amine functional group on the hydrophilicity and the surface charge of the gels. The adhesion of fibrinogen and blood cells was then methodically studied. Both types of gel are positively charged at pH 7.4, promoting fibrinogen and cell attachment. However, for the particular composition of 64% of DMAEMA in the hydrogel, results reveal that the adhesion of leukocytes was more important than that of erythrocytes and thrombocytes, thus suggesting that the control of the surface charge could lead to the selective adhesion of leukocytes. Based on these results, membranes were developed and tested in blood filtration for leukocyte depletion. Results prove that polypropylene membranes modified with a poly(DMAEMA- co -PEGMA) layer, containing 64% of DMAEMA can effectively lead to leukocyte depletion during blood filtration (99.6%) still maintaining a high erythrocytes recovery (98%). [ABSTRACT FROM AUTHOR]

A mixed protonic–electronic conductor made of La 5.5 W 0.45 Nb 0.15 Mo 0.4 O 11.25− δ (LWNM) has been developed by partial co-substitution of W with Nb and Mo in La 5.5 WO 11.25 − δ aiming to improve the hydrogen permeation property. A hydrogen permeation flux of 0.195 mL/min⋅cm 2 was obtained at 1000 °C with a mixture of 50% H 2 –50% He as the feed gas under dry condition. More importantly, there was no obvious decline of the hydrogen flux during 80 h operation even with CO 2 in the feed gas. [ABSTRACT FROM AUTHOR]

Abstract: Sulfonated polybenzothiazoles with benzimidazole moieties were successfully prepared by polycondensation. For comparison purpose, sulfonated polybenzothiazoles were also synthesized. Rigid-rod sulfonated polybenzothiazoles generally show poor solubility in organic solvents, whereas these sulfonated polybenzothiazoles with high sulfonation degree are soluble, but the membranes cast from them swell excessively in water. Thus they could not be used as proton exchange membranes (PEMs). The comparison study demonstrates that the incorporation of benzimidazole moieties to sulfonated polybenzothiazoles greatly enhances the solubility of products. The resulting copolymers thus could be cast into the membranes as PEMs. The benzimidazole moieties in the resulting polymers improve thermal properties, dimensional stability, tensile strength, Young''s modulus, and oxidative stability, but they decrease proton conductivity and the elongation at break, due to the ionic cross-linking and hydrogen bonds. Even so, sulfonated polybenzothiazoles with appropriate content of benzimidazole moieties (10mol%) could still display a high proton conductivity of 0.094Scm−1 at 80°C and an elongation at break of 26.1%. These ionomers exhibited excellent overall properties such as excellent mechanical properties, high thermal and oxidative stability, low swelling, and high proton conductivity, thus they might be a candidate for proton exchange membranes. [Copyright &y& Elsevier]

Two-dimensional (2D) Montmorillonite (MMT) membranes have been developed by exfoliation MMT nanosheets and vacuum filtration, and their separation performances were investigated in details. The hydrated lamellar MMT membrane with a thickness of 600 nm shows a water permeance of 212.2 L/m2·h·bar and a rejection rate of 95.6% for Direct Black 38 (DB38). Moreover, the lamellar MMT membrane maintained high stability under acid and alkaline solutions, and the separation performance changed slightly after soaking in 0.5 M H 2 SO 4 , 0.5 M NaOH and 0.5 M HCl solutions, respectively. The MMT membrane also exhibited good resistance to shearing force during a 48 h of cross-flow filtration with a slight decrease of water permeance. In addition, a high flux recovery ratio of 88.2% was achieved for the MMT membrane after filtration of BSA solution, suggesting an excellent antifouling property of the MMT membrane. The high water permeance, excellent stability and antifouling property make these 2D MMT membranes promising in water filtration. Image 1 • 2D MMT membranes with efficient water filtration were constructed. • MMT membrane maintained high stability under acid and alkaline solutions. • MMT membrane exhibited good resistance to shear force. • Excellent antifouling property with a high flux recovery ratio was achieved. [ABSTRACT FROM AUTHOR]

Hybrid WS 2 /GO two-dimensional membranes were developed to achieve finely molecular sieving. The size of nanochannels in WS 2 membrane became smaller and more regular after the introduction of GO nanosheets into WS 2 membrane according to XRD and separation results. The hydrated hybrid WS 2 /GO membrane with 15 wt% GO (GO15WS 2) exhibited high rejection (>90%) for dyes and ions with a hydrated radius above 4.9 Å. A water permeance of 159.6 L/m2·h·bar and a Methylene Blue (MnB) rejection of 96.3% were achieved through hydrated hybrid GO15WS 2 membrane, which was excellent compared with reported two-dimensional membranes based on TMDs. Moreover, the nanochannels in GO15WS 2 membrane also presented strong rigidity under a pressure loading up to 0.5 MPa. In addition, the half-dried GO15WS 2 membrane possessed high tolerance to shear stress, and the separation performance changed slightly during a 120 h-cross-flow filtration, which made the hybrid GO15WS 2 membrane promising in water filtration. • Hybrid 2D WS 2 /GO membranes with regular nanochannels were constructed. • Separation performances of WS 2 membrane were improved after GO intercalation. • GO15WS 2 membrane could separate molecules with hydrated radius above 4.9 Å. • Half-dried GO15WS 2 membrane possessed excellent stability against shear force. [ABSTRACT FROM AUTHOR]

Herein, we propose one novel strategy by layer-by-layer (LBL) self-assembly method to prepare two-dimensional (2D) laminar membranes assembled between sulfonated graphene oxide (S-GO) nanosheets and various cationic dyes on the polyethyleneimine (PEI) -modified Nylon-6 (PA6) substrate. The membrane performances are manipulated exquisitely by the charge of substrate, the assembled dye type, dye size, self-assembly layer number etc. The water permeance positively correlates with the height of assembled cationic dyes. The amido bonds or sulfamide bonds and π–π conjugation endow the resulted membrane with strong performance stability. Furthermore, by precisely selecting the size and charge the assembled dye, the prepared LBL GO membranes can efficiently separate mixed dyes in aqueous solution via charge repulsion or/and size sieving mechanism. For example, the separation selectivity of 39.2 for the mixed Rhodamine B/Ethyl Violet (RB/EV) dyes can be achieved with the LBL MV-0.25-2-2 membrane (it was assembled by 2 mmol L−1 Methyl violet solution for two S-GO layers with the Nylon-6 substrate modified with 0.25 wt % PEI aqueous solution). Simultaneously, the introduced cationic dyes endow these membranes with extra antibacterial capacity to both E. coli and S. aureus. [Display omitted] • Two-dimensional GO membranes were assembled with various cationic dyes. • Water permeance positively correlates with the height of assembled cationic dyes. • The membranes show good stability due to amido/sulfamide bonds and π–π conjugation. • The GO membranes can efficiently separate mixed dyes in aqueous solution. • The membranes exhibit extra antibacterial capacity to both E. coli and S. aureus. [ABSTRACT FROM AUTHOR]

Covalent organic frameworks (COFs) have attracted great interest as advanced membrane materials due to their uniform channel structure and high porosity. In this work, COF-LZU1/PES composite membranes were prepared via interfacial polymerization (IP) process, and the thin and defectless COFs active layers were successfully grown on poly (ether sulfone) (PES) microfiltration substrates with 1,3,5-triformylbenzene (TFB) and p-phenylenediamine (PDA) as precursors. The prepared COF-LZU1/PES composite membranes exhibit a high rejection rate (>99.0%) for the dyes with molecular size above 1.5 nm and nonselective permeation for inorganic salts (<12.0%). At the same time, a water permeance above 80.0 L m-2 h-1·bar-1 is achieved, which is much higher than many other membranes with similar rejections. Long-term filtration demonstrates that COF-LZU1/PES membranes have good water stability. The excellent water permeance, high dyes separation performance and great stability endow COF-LZU1/PES membranes the performance of removing dyes from saline wastewater. Image 1 • COF-LZU1/PES membranes were fabricated with microfiltration substrate. • The membranes exhibited high water permeance and dyes separation performance. • COF-LZU1/PES membranes exhibited superior dye desalination performance. [ABSTRACT FROM AUTHOR]

Abstract The PVDF membranes were prepared via thermally induced phase separation (TIPS) method with saline water as quenching bath and applied to the separation of oil/water emulsions. Surface pore size, permeation performance and other properties of the PVDF membranes were finely tuned by adjusting salt concentration in quenching bath. The results show that with the addition of NaCl in quenching bath, the thermal transfer resistance increases in the TIPS process due to the obvious increase of bath viscosity and the slight decline of thermal conductivity of saline solution. All the PVDF membranes present bi-continuously fibrillar structure in top surfaces. The fibrils are fused together and get thicker, and leads to rougher top surfaces due to the decline of cooling rate with the addition of NaCl in quenching bath. At the same time, the PVDF membranes exhibit expanded pore size and higher permeation flux for both pure water and oil/emulsions. The PVDF membrane of S20 (prepared with 20 wt% NaCl aqueous solution as quenching bath) exhibits the largest mean pore size and the highest pure water permeation flux of 2481.1 L m−2 h−1 bar−1. However, overhigh NaCl content leads to the inverse trend. For example, the PVDF membrane of S30 (quenching bath containing 30 wt% NaCl) exhibits a lightly decreased pore size and pure water permeation flux compared to S20. All of the PVDF membranes exhibit good oil rejections above 90.0% for surfactant-stabilized oil-in-water emulsions and above 95.0% for surfactant-free oil-in-water emulsions. Highlights • PVDF membranes are prepared via TIPS method with saline water as quenching bath. • Pore size and permeation performances of PVDF membranes are finely tuned. • Thermal transfer resistance rises with the increase of NaCl concentration. • Pore size of PVDF membranes increases with the increase of salt concentration. • Permeability of PVDF membranes increases with the increase of salt concentration. [ABSTRACT FROM AUTHOR]

Two-dimensional Ag/WS 2 hybrid membranes were developed to improve separation performance of WS 2 membrane by in situ self-reduction of AgNO 3 on WS 2 nanoflakes. With the increase of Ag content in Ag/WS 2 hybrid membrane, water flux increased as well because of increased interlayer spacing and more irregular stacking of WS 2 nanoflakes, while the rejection rates for dye molecules decreased. The hybrid membrane containing 6.92 wt% of Ag nanoparticles (Ag/WS 2 -2) presented optimal separation performance, exhibiting a EB rejection rate around 90% and a water permeance higher than 500 L/m2·h·bar. Moreover, Ag/WS 2 -2 membrane revealed excellent UV-driven self-cleaning ability by photodegradation of contaminant on membrane surface, and its water flux recovery rate was higher than 99.0%. The formation of Ag/WS 2 heterostructure can assist separation of photoinduced electrons and holes by transferring photoinduced electrons to Ag nanoparticles with enhanced photocatalytic activity. [Display omitted] - 2D Ag/WS 2 hybrid membranes were developed by in situ self-reduction of AgNO 3. - Improved separation performances were achieved after Ag decorated. - Ag/WS 2 membrane presented excellent self-cleaning ability by photocatalysis. [ABSTRACT FROM AUTHOR]

Permeability and mechanical strength normally present an opposite trend for separation membranes. There is a trade-off line of permeability vs. tensile strength for the prepared poly(vinylidene fluoride) (PVDF) membranes via thermally induced phase separation (TIPS) method. In this work, TIPS-prepared PVDF membranes were fabricated with water (PVDF T-water) and air (PVDF T-air) as quenching bath for comparatively studying. PVDF T-air membranes present larger average pore size, higher permeability and better mechanical strength than those of PVDF T-water membranes due to the lower cooling rate of air bath. It is wonderful that all PVDF T-air membranes can break though the trade-off line of permeability vs. tensile strength of TIPS-prepared PVDF membranes. The optimal membrane (M-A30) shows superior performance, such as ultrahigh water flux of 3275 L m−2 h−1·bar−1 and tensile strength of 5.7 MPa. Additionally, this research provides a feasible method to regulate the morphology, pore size and permeability of TIPS-prepared PVDF membranes. • PVDF membranes (PVDF T-air) are prepared via TIPS method with air quenching bath. • PVDF T-air membranes overcome the upperbound of permeability vs. tensile strength. • PVDF T-air membranes have much higher permeability than PVDF T-water membranes. • Pore size increases with the increase of quenching temperature. [ABSTRACT FROM AUTHOR]

Janus membrane is an emerging separation material due to its unique separation performance. The asymmetric surface wettability on its two surfaces is crucial for a Janus membrane. In this work, robust Janus polyvinylidene fluoride (PVDF) membranes were prepared via thermal induced phase separation (TIPS) accompanied with spray-coating method. The two surfaces of TIPS-prepared PVDF membranes were rapidly deposited with polydopamine/polyethyleneimine (PDA/PEI) and micro-/nano-scale silica particles crosslinking with diphenyldichlorosilane respectively. The spray-coating endows the Janus membranes with superhydrophilicity and superhydrophobicity on its opposite surfaces. The optimized membrane of M-A0.9B0.2 presents an asymmetric surface wettability. Its hydrophilic surface has a water contact angle (WCA) of 11.2°, while the hydrophobic surface has a WCA of 169.9° as well as a sliding angle of <1°. The superhydrophilic surface allows water to quickly pass through the membrane and oil phase is trapped; while oil can penetrate through the membrane and water is rejected by the superhydrophobic surface. The Janus membranes show excellent separation performance with the highest permeation of 2060.5 L m−2 h−1·bar−1 accompanied with above 94.0% oil rejection for toluene-in-water emulsion and the highest permeation of 1769.0 L m−2 h−1·bar−1 accompanied with above 97.0% water rejection for water-in-toluene emulsion using the opposite surfaces. Image 1 • A robust Janus membrane with TIPS-prepared PVDF substrate. • Superhydrophilic and superhydrophobic opposite surfaces were constructed. • The Janus membrane can efficiently separate both O/W and W/O emulsions. [ABSTRACT FROM AUTHOR]