Imidazolium group prompted alkaline anion-exchange membrane with high performance for efficient electrochemical CO_(2) conversion

Development of high-performance hydroxide-conductive membranes is a focus research subject owing to promising applications in electrochemical reduction of CO_(2)(eCO_(2)RR).However,few satisfactory membranes have been developed to maximize the performance of CO_(2) electrolyzers,despite its role as the core in regulating ion transport and preventing product crossover or fuel loss.Herein,we report the synthesis of alkaline anion-exchange membranes fabricated by poly(vinyl-alcohol)(PVA)and poly[(3-methyl-1-vinylimidazoliummethylsulfate)-co-(1-vinylpyrrolidone)](PQ44)for use in CO_(2) electrolysis.Owing to the unique imidazolium ring structure coupled with a three-dimensional semiinterpenetrating porous internal architecture,the PVA/PQ44-OH-membranes provide a high hydroxide conductivity(21.47 mS cm^(-1)),preferable mechanical property and thermal stability.In particular,the eCO_(2)RR used PVA/PQ44-OH^(-) as electrolyte membrane realized a charming Faradaic efficiency(88%)and partial current density(29 mA cm^(-2))at0.96 VRHE and,delivered the excellent durability over 20 h electrolysis in 0.5 mol L^(-1) KHCO_(3) electrolyte.Notably,it can even enable an ultrahigh current density beyond 100 mA cm^(-2) at^(-1).11 VRHE when the electrolyte was KOH instead,and produced the FEHCOOof 85%at a low potential of0.81 VRHE,superior to both commercial alkaline A201 and acidic Nafion117 membrane.

Synthesis and characterization of quaternized poly(phthalazinone ether sulfone ketone)for anion-exchange membrane

Chloromethylated poly（phthalazinone ether sulfone ketone） （CMPPESK） was prepared from poly（phthalazinone ether sulfone ketone） （PPESK） using chloromethyl octyl ethers （CMOE） with lower toxicity as chloromethylated regent. CMPPESK was soluble in N-methyl-2-pyrrolidone （NMP）, N,N-dimethylacetamide （DMAc） and chloroform. Quaternized poly（phthalazinone ether sulfone ketone） （QAPPESK） was prepared from CMPPESK by quaternization. QAPPESK had excellent solvent resistance, which was only partly soluble in sulfuric acid （98%） and swollen in N,N-dimethylformamide （DMF）. The vanadium redox flow battery （V-RFB） using QAPPESK anion-exchange membrane had better performance with 88.3% of overall energy efficiency.

Phosphate removal from aqueous solution by Donnan dialysis with anion-exchange membrane

The removal of phosphate from aqueous solution by Donnan dialysis with anion-exchange membrane was investigated.The results show that phosphate could be removed from aqueous solution without supplying external high pressure or electrical potential.Under the conditions of influent phosphate of 2.0 mg/L,counterion(Cl-)concentration of 0.1 mol/L,stirring speed of 500 r/min and phase temperature of 298 K,the removal of phosphate achieves 70.0%.Decreasing counterion concentration has little influence on the removal of phosphate,but phosphate amount in anion-exchange membrane increases significantly.With the increase of stirring speed and phase temperature,the removal efficiency of phosphate greatly is improved.Existing forms of phosphate in aqueous solution affected transport of phosphate and only strong acidic pH of feed solution(pH=3.0)decreases the removal of phosphate.Transport of phosphate is also accompanied by change of pH value of feed solution.In consequence,it might be a promise potential process for phosphate advanced wastewater treatment,especially in the area where high salted nature water can be utilized.

A RAPID METHOD TO DETERMINE DIFFUSION COEFFICIENTS OF COUNTER-IONS IN AN ION-EXCHANGE MEMBRANE

1 INTRODUCTIONRapid and precise methods to obtain the diffusion coefficients of counter-ions are im-portant for the characterization of ion exchange membranes.Many theoreticaldescriptions of ion transport in ion exchange membranes have been developed by usingthe principles of irreversible thermodynamics,or the Nernst-Planck equations.Fick’s law can also be used for the description of the transport of ions with equaldiffusivity.However,for counter-ions of different diffusivities,Nerst-Planck

FREE ALKALI RECOVERY FROM NaOH LEACHING LIQUOR OF TUNGSTEN ORE BY ELECTROLYSIS WITH ION-EXCHANGE MEMBRANE

Caustic soda leaching liquor of tungsten ore always contains a certain amount of free alkali. General method of removing free alkali in the liquor is to neutralize it by inorganic acid. A new method, i.e. applying electrolysis with ion exchange membrane to recover free alkali from caustic soda leaching liquor of tungsten ore, was proposed in the paper. In the electrolysis cell the effective area of membrane is 100 mm×100 mm, the anode is β PbO 2 plated at screen of titanium net, the cathode is active nickel plated at screen of stainless steel net, and the membrane is a kind of perfluorsulphonic acid membrane. Some effect factors of electrolysis process including the NaOH concentration in anolyte and catholyte, distance between electrodes, temperature, current density, are investigated. The results show that, by choosing proper operating condition, the specific energy consumption can be controlled within 2 kWh·kg -1 NaOH. Electrolysis with ion exchange membrane can not only recover free alkali from caustic soda leaching liquor, reduce the consumption of inorganic acid, but also utilize the hydrogen gas produced in the process to produce tungsten powder.

Transport Properties of Novel Hybrid Cation-Exchange Membranes on the Base of MF-4SC and Halloysite Nanotubes

The diffusion permeability through new hybrid materials based on a Nafion-type membrane (MF- 4SC) and nanotubes of halloysite is investigated using the Nernst-Planck approach. A method of quantitative evaluation of physicochemical parameters (averaged and individual diffusion coefficients and averaged distribution coefficients of ion pairs in the membrane) of system “electrolyte solution—ion-exchange membrane—water”, which was proposed earlier, is further developed. The parameters of hybrid membranes on the base of MF-4SC and nanotubes of halloysite (5% wt and 8% wt) are obtained from experimental data on diffusion permeability of NaCl solutions using theoretical calculations. New model of three-layer membrane system can be used for refining calculated results with taking into account both diffusive layers. It is shown that adding of halloysite nanotubes into the membrane volume noticeably affects exchange capacity as well as structural and transport characteristics of original perfluorinated membranes. Hybrid membranes on the base of MF-4SC and halloysite nanotubes can be used in fuel cells and catalysis.

Advancing ion-exchange membranes to ion-selective membranes:principles,status,and opportunities

Ion-exchange membranes(IEMs)are utilized in numerous established,emergent,and emerging applications for water,energy,and the environment.This article reviews the five different types of IEM selectivity,namely charge,valence,specific ion,ion/solvent,and ion/uncharged solute selectivities.Technological pathways to advance the selectivities through the sorption and migration mechanisms of transport in IEM are critically analyzed.Because of the underlying principles governing transport,efforts to enhance selectivity by tuning the membrane structural and chemical properties are almost always accompanied by a concomitant decline in permeability of the desired ion.Suppressing the undesired crossover of solvent and neutral species is crucial to realize the practical implementation of several technologies,including bioelectrochemical systems,hypersaline electrodialysis desalination,fuel cells,and redox flow batteries,but the ion/solvent and ion/uncharged solute selectivities are relatively understudied,compared to the ion/ion selectivities.Deepening fundamental understanding of the transport phenomena,specifically the factors underpinning structure-property-performance relationships,will be vital to guide the informed development of more selective IEMs.Innovations in material and membrane design offer opportunities to utilize ion discrimination mechanisms that are radically different from conventional IEMs and potentially depart from the putative permeability-selectivity tradeoff.Advancements in IEM selectivity can contribute to meeting the aqueous separation needs of water,energy,and environmental challenges.

Towards reliable assessment of hydrogen oxidation electrocatalysts for anion-exchange membrane fuel cells

Recent advancement of proton exchange membrane fuel cells has led to commercial sales of fuel-cell cars but market barrier exists because this technology heavily relies on platinum catalyst.Given the permission of adopting platinum-group-metal-free catalysts,anion-exchange membrane fuel cell has received notable attention.However,the sluggish kinetics of anodic hydrogen oxidation reaction(HOR)largely limit the cell efficiency.Although many high-performance HOR catalysts have been reported,there are analytical uncertainties in the literature concerning the assessment of the catalyst activity.Here we determine the origin of false HOR currents in the recorded polarization curves and propose a rigorous approach to eliminate them.We unveil experimentally the uncertainties of obtaining exchange current densities(j0)using Tafel plot from Bulter–Volmer equation and recommend employing the micro-polarization region method.For bulky catalysts that cannot establish a well-defined diffusion layer,we suggest applying external stirring bar to offer certain level of enforced convection and using j0 to compare the activity.

Effects of ion-exchange on the pervaporation performance and microstructure of NaY zeolite membrane

Pervaporation performance of NaY zeolite membranes is improved by ion-exchange with di-valent nitrate salt.Different nitrate salts,including Co(NO_(3))_(2),Mg(NO_(3))_(2),Zn(NO_(3))_(2),Ca(NO_(3))_(2),Cu(NO_(3))_(2),KNO_(3),and AgNO_(3),have great effects on the channel structure and water affinity of the NaY zeolite membrane.When the concentration of nitrate salt,ion-exchange temperature and time are 0.1 mol·L^(-1),50℃and 2 h,the ion-exchange degree order of NaY zeolites is Ag^(+)>K^(+)>Ca^(2+)>Zn^(2+)>>Co^(2+)>Mg^(2+).Especially,Ag^(+)and K^(+)cation exchange degree of NaY zeolites are achieved to 96.54% and 82.77% in this work.BET surface,total pore capacity,pore size distribution and water contact angle of the ion-exchanged NaY zeolites are all disordered by mono-and di-valent cations.Di-valent nitrate salt is favor for increasing the dehydration performance of NaY zeolite membranes by ion-exchange.When the ion-exchange solution is Zn(NO_(3))_(2),the total flux variation and separation factor variation of the NaY membrane(M-5)are -45% and 230% for separation of 10%(mass)H_(2)O/EtOH mixture by pervaporation,and the ion-exchanged membranes showed good reproducibility.

Sustained release of vascular endothelial growth factor A and basic fibroblast growth factor from nanofiber membranes reduces oxygen/glucose deprivation-induced injury to neurovascular units

Upregulation of vascular endothelial growth factor A/basic fibroblast growth factor(VEGFA/b FGF)expression in the penumbra of cerebral ischemia can increase vascular volume,reduce lesion volume,and enhance neural cell proliferation and differentiation,thereby exerting neuroprotective effects.However,the beneficial effects of endogenous VEGFA/b FGF are limited as their expression is only transiently increased.In this study,we generated multilayered nanofiber membranes loaded with VEGFA/b FGF using layer-by-layer self-assembly and electrospinning techniques.We found that a membrane containing 10 layers had an ideal ultrastructure and could efficiently and stably release growth factors for more than 1 month.This 10-layered nanofiber membrane promoted brain microvascular endothelial cell tube formation and proliferation,inhibited neuronal apoptosis,upregulated the expression of tight junction proteins,and improved the viability of various cellular components of neurovascular units under conditions of oxygen/glucose deprivation.Furthermore,this nanofiber membrane decreased the expression of Janus kinase-2/signal transducer and activator of transcription-3(JAK2/STAT3),Bax/Bcl-2,and cleaved caspase-3.Therefore,this nanofiber membrane exhibits a neuroprotective effect on oxygen/glucose-deprived neurovascular units by inhibiting the JAK2/STAT3 pathway.

Development of advanced anion exchange membrane from the view of the performance of water electrolysis cell

Green hydrogen produced by water electrolysis combined with renewable energy is a promising alternative to fossil fuels due to its high energy density with zero-carbon emissions.Among water electrolysis technologies,the anion exchange membrane(AEM) water electrolysis has gained intensive attention and is considered as the next-generation emerging technology due to its potential advantages,such as the use of low-cost non-noble metal catalysts,the relatively mature stack assembly process,etc.However,the AEM water electrolyzer is still in the early development stage of the kW-level stack,which is mainly attributed to severe performance decay caused by the core component,i.e.,AEM.Here,the review comprehensively presents the recent progress of advanced AEM from the view of the performance of water electrolysis cells.Herein,fundamental principles and critical components of AEM water electrolyzers are introduced,and work conditions of AEM water electrolyzers and AEM performance improvement strategies are discussed.The challenges and perspectives are also analyzed.

Elaidic acid leads to mitochondrial dysfunction via mitochondria-associated membranes triggers disruption of mitochondrial calcium fluxes

Elaidic acid(EA)stimulation can lead to endoplasmic reticulum stress(ERS),accompanied by a large release of Ca^(2+),and ultimately the activation of NLRP3 inflammasome in Kupffer cells(KCs).Mitochondrial instability or dysfunction may be the key stimulating factors to activate NLRP3 inflammasome,and sustained Ca^(2+)transfer can result in mitochondrial dysfunction.We focused on KCs to explore the damage to mitochondria by EA.After EA stimulation,cells produced an oxidative stress(OS)response with a significant increase in ROS release.Immunoprecipitation experiments and the addition of inhibitors revealed that the increase in the level of intracellular Ca^(2+)led to Ca^(2+)accumulation in the mitochondrial matrix via mitochondria-associated membranes(MAMs).This was accompanied by a significant release of m ROS,loss of MMP and ATP,and a significant increase in mitochondrial permeability transition pore opening,ultimately leading to mitochondrial instability.These findings confirmed the mechanism that EA induced mitochondrial Ca^(2+)imbalance in KCs via MAM,ultimately leading to mitochondrial dysfunction.Meanwhile,EA induced OS and the decrease of MMP and ATP in rat liver,and significant lesions were found in liver mitochondria.Swelling of the inner mitochondrial cristae and mitochondrial vacuolization occurred,with a marked increase in lipid droplets.

Amino-functionalized UiO-66-doped mixed matrix membranes with high permeation performance and fouling resistance

For the reduction of bovine serum proteins from wastewater,a novel mixed matrix membrane was prepared by functionalizing the substrate material polyaryletherketone(PAEK),followed by carboxyl groups(C-SPAEKS),and then adding amino-functionalized UiO-66-NH_(2)(Am-UiO-66-NH_(2)).Aminofunctionalization of UiO-66 was accomplished by melamine,followed by an amidation reaction to immobilize Am-UiO-66-NH_(2),which was immobilized on the surface of the membrane as well as in the pore channels,which enhanced the hydrophilicity of the membrane surface while increasing the negative potential of the membrane surface.This nanoparticle-loaded ultrafiltration membrane has good permeation performance,with a pure water flux of up to 482.3 L·m^(-2)·h^(-1) for C-SPAEKS/AmUiO-66-NH_(2) and a retention rate of up to 98.7%for bovine serum albumin(BSA)-contaminated solutions.Meanwhile,after several hydrophilic modifications,the flux recovery of BSA contaminants by this series of membranes increased from 56.2%to 80.55%of pure membranes.The results of ultra-filtration flux time tests performed at room temperature showed that the series of ultrafiltration membranes remained relatively stable over a test time of 300 min.Thus,the newly developed mixed matrix membrane showed potential for high efficiency and stability in wastewater treatment containing bovine serum proteins.

Plasma‐oxidized 2D MXenes subnanochannel membrane for high‐performance osmotic energy conversion

Nanofluidic channels inspired by electric eels open a new era of efficient harvesting of clean blue osmotic energy from salinity gradients.Limited by less charge and weak ion selectivity of the raw material itself,energy conversion through nanofluidic channels is still facing considerable challenges.Here,a facile and efficient strategy to enhance osmotic energy harvesting based on drastically increasing surface charge density of MXenes subnanochannels via oxygen plasma is proposed.This plasma could break Ti–C bonds in the MXenes subnanochannels and effectively facilitate the formation of more Ti–O,C═O,O–OH,and rutile with a stronger negative charge and work function,which leads the surface potential of MXenes membrane to increase from 205 to 430 mV.This significant rise of surface charge endows the MXenes membrane with high cation selectivity,which could make the output power density of the MXenes membrane increase by 248.2%,reaching a high value of 5.92Wm^(−2)in the artificial sea‐river water system.Furthermore,with the assistance of low‐quality heat at 50℃,the osmotic power is enhanced to an ultrahigh value of 9.68Wm^(−2),which outperforms those of the state‐of‐the‐art two‐dimensional(2D)nanochannel membranes.This exciting breakthrough demonstrates the enormous potential of the facile plasma‐treated 2D membranes for osmotic energy harvesting.

Milk fat globule membrane supplementation protects againstβ-lactoglobul-ininduced food allergy in mice via upregulation of regulatory T cells and enhancement of intestinal barrier in a microbiota-derived short-chain fatty acids manner

Milk fat globule membrane(MFGM),which contains abundant glycoproteins and phospholipids,exerts beneficial effects on intestinal health and immunomodulation.The aim of this study was to evaluate the protective effects and possible underlying mechanisms of MFGM on cow’s milk allergy(CMA)in aβ-lactoglobulin(BLG)-induced allergic mice model.MFGM was supplemented to allergic mice induced by BLG at a dose of 400 mg/kg body weight.Results demonstrated that MFGM alleviated food allergy symptoms,decreased serum levels of lipopolysaccharide,pro-inflammatory cytokines,immunoglobulin(Ig)E,Ig G1,and Th2 cytokines including interleukin(IL)-4,while increased serum levels of Th1 cytokines including interferon-γand regulatory T cells(Tregs)cytokines including IL-10 and transforming growth factor-β.MFGM modulated gut microbiota and enhanced intestinal barrier of BLG-allergic mice,as evidenced by decreased relative abundance of Desulfobacterota,Rikenellaceae,Lachnospiraceae,and Desulfovibrionaceae,while increased relative abundance of Bacteroidetes,Lactobacillaceae and Muribaculaceae,and enhanced expressions of tight junction proteins including Occludin,Claudin-1 and zonula occludens-1.Furthermore,MFGM increased fecal short-chain fatty acids(SCFAs)levels,which elevated G protein-coupled receptor(GPR)43 and GPR109A expressions.The increased expressions of GPR43 and GPR109A induced CD103+dendritic cells accumulation and promoted Tregs differentiation in mesenteric lymph node to a certain extent.In summary,MFGM alleviated CMA in a BLG-induced allergic mice model through enhancing intestinal barrier and promoting Tregs differentiation,which may be correlated with SCFAs-mediated activation of GPRs.These findings suggest that MFGM may be useful as a promising functional ingredient against CMA.

Machine learning for membrane design and discovery

Membrane technologies are becoming increasingly versatile and helpful today for sustainable development.Machine Learning(ML),an essential branch of artificial intelligence(AI),has substantially impacted the research and development norm of new materials for energy and environment.This review provides an overview and perspectives on ML methodologies and their applications in membrane design and dis-covery.A brief overview of membrane technologies isfirst provided with the current bottlenecks and potential solutions.Through an appli-cations-based perspective of AI-aided membrane design and discovery,we further show how ML strategies are applied to the membrane discovery cycle(including membrane material design,membrane application,membrane process design,and knowledge extraction),in various membrane systems,ranging from gas,liquid,and fuel cell separation membranes.Furthermore,the best practices of integrating ML methods and specific application targets in membrane design and discovery are presented with an ideal paradigm proposed.The challenges to be addressed and prospects of AI applications in membrane discovery are also highlighted in the end.

Suppression of current-induced membrane discharge of bipolar membranes by regulating ion crossover transport

Bipolar membranes(BPMs)exhibit the unique capability to regulate the operating environment of electrochemical system through the water dissociation-combination processes.However,the industrial utilization of BPMs is limited by instability and serious energy consumption.The current-induced membrane discharge(CIMD)at high-current conditions has a negative influence on the performance of anion-exchange membranes,but the underlying ion transport mechanisms in the BPMs remain unclear.Here,the CIMD-coupled Poisson-Nernst-Planck(PNP)equations are used to explore the ion transport mechanisms in the BPMs for both reverse bias and forward bias at neutral and acid-base conditions.It is demonstrated that the CIMD effect in the reverse-bias mode can be suppressed by enhancing the diffusive transport of salt counter-ions(Na^(+)and Cl^(−))into the BPMs,and that in the forward-bias mode with acid-base electrolytes can be suppressed by matching the transport rate of water counter-ions(H_(3)O^(+)and OH^(−)).Suppressing the CIMD can promote the water dissociation in the reverse-bias mode,as well as overcome the plateau of limiting current density and reduce the interfacial blockage of salt co-ions(Cl^(−))in the anion-exchange layer in the forward-bias mode with acid-base electrolytes.Our work highlights the importance of regulating ion crossover transport on improving the performance of BPMs.

Regulation of interlayer channels of graphene oxide nanosheets in ultra-thin Pebax mixed-matrix membranes for CO_(2) capture

For the application of carbon capture by membrane process,it is crucial to develop a highly permeable CO_(2)-selective membrane.In this work,we reported an ultra-thin polyether-block-amide(Pebax)mixedmatrix membranes(MMMs)incorporated by graphene oxide(GO),in which the interlayer channels were regulated to optimize the CO_(2)/N_(2) separation performance.Various membrane preparation conditions were systematically investigated on the influence of the membrane structure and separation performance,including the lateral size of GO nanosheets,GO loading,thermal reduction temperature,and time.The results demonstrated that the precisely regulated interlayer channel of GO nanosheets can rapidly provide CO_(2)-selective transport channels due to the synergetic effects of size sieving and preferential adsorption.The GO/Pebax ultra-thin MMMs exhibited CO_(2)/N_(2) selectivity of 72 and CO_(2) permeance of 400 GPU(1 GPU=106 cm^(3)(STP)·cm^(2)·s^(-1)·cmHg^(-1)),providing a promising candidate for CO_(2) capture.

Membrane tension evolution and mechanical regulation of melittin-induced membrane poration

Membrane tension plays a crucial role in various fundamental cellular processes,with one notable example being the T cell-mediated elimination of tumor cells through perforin-induced membrane perforation by amplifying cellular force.However,the mechanisms governing the regulation of biomolecular activities at the cell interface by membrane tension remain elusive.In this study,we investigated the correlation between membrane tension and poration activity of melittin,a prototypical pore-forming peptide,using dynamic giant unilamellar vesicle leakage assays combined with flickering tension analysis,molecular dynamics simulations,and live cell assays.The results demonstrate that an increase in membrane tension enhances the activity of melittin,particularly near its critical pore-forming concentration.Moreover,peptide actions such as binding,insertion,and aggregation in the membrane further influence the evolution of membrane tension.Live cell experiments reveal that artificially enhancing membrane tension effectively enhances melittin’s ability to induce pore formation and disrupt membranes,resulting in up to a ten-fold increase in A549 cell mortality when exposed to a concentration of 2.0-μg·mL^(-1)melittin.Our findings elucidate the relationship between membrane tension and the mechanism of action as well as pore-forming efficiency of melittin,while providing a practical mechanical approach for regulating functional activity of molecules at the cell-membrane interface.

Preparation and Performance of Organically Modified Montmorillonite Composite Separation Membrane

A new composite separation membrane was developed by using organically modified montmorillonite(OMMT)as an additive.The effects of OMMT on the modification and properties of PVDF composite membranes were investigated.It is found that different kinds and amounts of OMMT into the casting solution can obviously change the pure water flux,separation performance and hydrophilicity of composite membrane in varying degrees.When the TA/PDA-MMT was 0.5 wt%,the pure water flux of the membrane reached the maximum,which was 584.7 L/(m^(2)·h),about 6 times that of the original membrane.The OMMT/PVDF composite membrane had good hydrophilicity and stability in the treatment of oily wastewater.The development of novel OMMT/PVDF composite membrane will provide a new idea for solving the problem of oily wastewater treatment.