Pub Date : 2025-04-08DOI: 10.1016/j.memsci.2025.124081
Antoine Chamoun-Farah, Louise M. Cañada, Joan F. Brennecke, Benny D. Freeman
Supported ionic liquid membranes (SILMs), containing phosphonium ionic liquids with aprotic N-heterocyclic anions (AHA ILs) in an inert inorganic support, were tested under both dry and humidified (40 % RH) mixed-gas conditions down to 420 ppm CO2 in N2 at 35 °C. In the dry case, the best performing IL, triethyl(octyl)phosphonium 4-bromopyrazolide ([P2228][4-BrPyra]) exhibited mixed-gas CO2 permeabilities and CO2/N2 permeability selectivities as high as 26,800 barrer and 7,000, respectively. In the presence of humidity, the CO2 permeability and CO2/N2 selectivity increased to 49,100 barrer and 13,200, respectively, and these are the highest reported combination in the literature. Humidity amplifies CO2 permeabilities and CO2/N2 permeability selectivities through increases in CO2 capacity due to bicarbonate formation and through faster mobility of the mobile carrier from decreased viscosity. N2 permeability stayed roughly invariant in the presence of humidity, likely from competing effects of viscosity reduction and lower N2 solubility.
{"title":"Supported ionic liquid membranes (SILMs) with exceptional selectivity and permeability for dilute CO2 separations","authors":"Antoine Chamoun-Farah, Louise M. Cañada, Joan F. Brennecke, Benny D. Freeman","doi":"10.1016/j.memsci.2025.124081","DOIUrl":"10.1016/j.memsci.2025.124081","url":null,"abstract":"<div><div>Supported ionic liquid membranes (SILMs), containing phosphonium ionic liquids with aprotic <em>N</em>-heterocyclic anions (AHA ILs) in an inert inorganic support, were tested under both dry and humidified (40 % RH) mixed-gas conditions down to 420 ppm CO<sub>2</sub> in N<sub>2</sub> at 35 °C. In the dry case, the best performing IL, triethyl(octyl)phosphonium 4-bromopyrazolide ([P<sub>2228</sub>][4-BrPyra]) exhibited mixed-gas CO<sub>2</sub> permeabilities and CO<sub>2</sub>/N<sub>2</sub> permeability selectivities as high as 26,800 barrer and 7,000, respectively. In the presence of humidity, the CO<sub>2</sub> permeability and CO<sub>2</sub>/N<sub>2</sub> selectivity increased to 49,100 barrer and 13,200, respectively, and these are the highest reported combination in the literature. Humidity amplifies CO<sub>2</sub> permeabilities and CO<sub>2</sub>/N<sub>2</sub> permeability selectivities through increases in CO<sub>2</sub> capacity due to bicarbonate formation and through faster mobility of the mobile carrier from decreased viscosity. N<sub>2</sub> permeability stayed roughly invariant in the presence of humidity, likely from competing effects of viscosity reduction and lower N<sub>2</sub> solubility.</div></div>","PeriodicalId":368,"journal":{"name":"Journal of Membrane Science","volume":"727 ","pages":"Article 124081"},"PeriodicalIF":8.4,"publicationDate":"2025-04-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143830178","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-04-07DOI: 10.1016/j.memsci.2025.124077
Qian Xu , Yiyan Sun , Zhaoyang Tan , Weijuan Guo , Fujun Li , Xinran Hou , Yu Guo , Feichao Wu
Metal-organic framework (MOF) membranes, particularly cobalt-based gallate (Co-gallate) membranes, possess great potential for the efficient separation of ethylene/ethane (C2H4/C2H6) mixtures due to their excellent sieving properties. However, the poor nucleation of MOF crystals on the substrate poses a challenge in the fabrication of high-quality Co-gallate membranes. In this work, we propose a facile and environmentally friendly approach to prepare continuous Co-gallate membranes at room temperature via magnetic field assistance. The external magnetic field, perpendicular to the substrate surface, promotes directional ion movement, improves the coordination ability of metal centers, and promotes deprotonation of ligands. These collectively facilitate the crystallization and growth of MOF crystals on the substrate by advancing MOF nucleation and enhancing nucleation density. The controllable growth of MOF membranes can also be achieved under the influence of magnetic field. The obtained Co-gallate membrane has a thickness of merely 400 nm, and exhibits superior performance in C2H4/C2H6 separation. This work highlights the considerable potential of magnetic fields in the fabrication of various MOF membranes for diverse applications.
{"title":"Facile synthesis of Co-gallate membranes under magnetic field for effective ethylene/ethane separation","authors":"Qian Xu , Yiyan Sun , Zhaoyang Tan , Weijuan Guo , Fujun Li , Xinran Hou , Yu Guo , Feichao Wu","doi":"10.1016/j.memsci.2025.124077","DOIUrl":"10.1016/j.memsci.2025.124077","url":null,"abstract":"<div><div>Metal-organic framework (MOF) membranes, particularly cobalt-based gallate (Co-gallate) membranes, possess great potential for the efficient separation of ethylene/ethane (C<sub>2</sub>H<sub>4</sub>/C<sub>2</sub>H<sub>6</sub>) mixtures due to their excellent sieving properties. However, the poor nucleation of MOF crystals on the substrate poses a challenge in the fabrication of high-quality Co-gallate membranes. In this work, we propose a facile and environmentally friendly approach to prepare continuous Co-gallate membranes at room temperature via magnetic field assistance. The external magnetic field, perpendicular to the substrate surface, promotes directional ion movement, improves the coordination ability of metal centers, and promotes deprotonation of ligands. These collectively facilitate the crystallization and growth of MOF crystals on the substrate by advancing MOF nucleation and enhancing nucleation density. The controllable growth of MOF membranes can also be achieved under the influence of magnetic field. The obtained Co-gallate membrane has a thickness of merely 400 nm, and exhibits superior performance in C<sub>2</sub>H<sub>4</sub>/C<sub>2</sub>H<sub>6</sub> separation. This work highlights the considerable potential of magnetic fields in the fabrication of various MOF membranes for diverse applications.</div></div>","PeriodicalId":368,"journal":{"name":"Journal of Membrane Science","volume":"726 ","pages":"Article 124077"},"PeriodicalIF":8.4,"publicationDate":"2025-04-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143815365","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-04-07DOI: 10.1016/j.memsci.2025.124087
Ziyang Guo , Runhao Li , Yumei Wang , Haoling Zhang , Haitao Wang , Yue Sun , Na Chang
Loose nanofiltration membranes, particularly those fabricated using hydroxyl-based monomers, have garnered considerable interest due to their exceptional ability to reject dyes while allowing the passage of monovalent salts. These properties make them highly suitable for applications in resource recovery and the treatment of saline textile wastewater. In this study, a series of well-designed macrocyclic polyester loose nanofiltration membranes were fabricated through classic interfacial polymerization, involving the reaction of an aqueous monomer containing pillar[n]arenes with their intrinsic cavity structure and an organic phase containing 1,3,5-benzenetricarboxylic acid chloride. Notably, triethylamine was employed as an acid-binding agent to enhance the solubility and esterification reactivity of P[n], facilitating the formation of an ultrathin polyester selective layer (56–85 nm). The macrocyclic pillar[n]arene-based polyester loose nanofiltration membranes exhibited a smooth, negatively charged surface and achieved a high water permeance of 89.35 L m−2 h−1 bar−1, good dye rejection (97.92 % for Congo red, 95.27 % for Methyl blue), and low rejection of inorganic salts (4.3 % for NaCl, 3.5 % for MgCl2). Remarkably, the Congo red/NaCl mixture selectivity reached 46.0. These macrocyclic loose nanofiltration membranes showed stable performance during continuous filtration, confirming the significant potential of macrocyclic pillar[n]arene-based polyester loose nanofiltration membranes for treating salt-containing textile wastewater.
{"title":"Macrocyclic pillararene-based polyester loose nanofiltration membranes for efficient dye/salt separation","authors":"Ziyang Guo , Runhao Li , Yumei Wang , Haoling Zhang , Haitao Wang , Yue Sun , Na Chang","doi":"10.1016/j.memsci.2025.124087","DOIUrl":"10.1016/j.memsci.2025.124087","url":null,"abstract":"<div><div>Loose nanofiltration membranes, particularly those fabricated using hydroxyl-based monomers, have garnered considerable interest due to their exceptional ability to reject dyes while allowing the passage of monovalent salts. These properties make them highly suitable for applications in resource recovery and the treatment of saline textile wastewater. In this study, a series of well-designed macrocyclic polyester loose nanofiltration membranes were fabricated through classic interfacial polymerization, involving the reaction of an aqueous monomer containing pillar[n]arenes with their intrinsic cavity structure and an organic phase containing 1,3,5-benzenetricarboxylic acid chloride. Notably, triethylamine was employed as an acid-binding agent to enhance the solubility and esterification reactivity of P[n], facilitating the formation of an ultrathin polyester selective layer (56–85 nm). The macrocyclic pillar[n]arene-based polyester loose nanofiltration membranes exhibited a smooth, negatively charged surface and achieved a high water permeance of 89.35 L m<sup>−2</sup> h<sup>−1</sup> bar<sup>−1</sup>, good dye rejection (97.92 % for Congo red, 95.27 % for Methyl blue), and low rejection of inorganic salts (4.3 % for NaCl, 3.5 % for MgCl<sub>2</sub>). Remarkably, the Congo red/NaCl mixture selectivity reached 46.0. These macrocyclic loose nanofiltration membranes showed stable performance during continuous filtration, confirming the significant potential of macrocyclic pillar[n]arene-based polyester loose nanofiltration membranes for treating salt-containing textile wastewater.</div></div>","PeriodicalId":368,"journal":{"name":"Journal of Membrane Science","volume":"727 ","pages":"Article 124087"},"PeriodicalIF":8.4,"publicationDate":"2025-04-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143814869","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-04-07DOI: 10.1016/j.memsci.2025.124085
Chenlu Liu , Xiaoting Feng , Keming Zhang , Xiaohe Tian , Qingnan Wang , Yanting Tang , Yueyangchao Yu , Tianhe Gu , Rui Zhang , Xiangyu Liu , Shaofei Wang
Polyamide membranes with rigid twisted structures show excellent permeance and rejection in the field of organic solvent nanofiltration (OSN). However, challenges such as low reactivity, complex synthesis procedures, and high costs persist for certain rigid and twisted monomers, posing obstacles in their synthesis or application processes. To address these challenges, we adopt a low-cost rigid and twisted tetraamine monomer, N,N,N’,N’-tetrakis(4-aminophenyl)-1,4-benzenediamine (TK), for the preparation of polyamide OSN membranes through interfacial polymerization with various acyl chlorides. TK is effectively introduced into the polyamide chain, which involves not only the reactivity of monomers, but also the influence of monomer angle configuration on the formation of chain segments, forming different rigid networks and enabling the active layer to have excellent stability and high porosity. Consequently, the rigid twisted polyamide OSN membranes exhibit a methanol permeance of 13.8 L m-2 h-1 bar-1 and a molecular weight cut-off (MWCO) of 266 Da, outperforming many reported membranes. This work highlights the use of TK as a promising, cost-effective monomer to engineer high-performance OSN membranes with tailored structural features, offering a practical solution for enhanced organic solvent separation processes.
{"title":"Polyamide membranes with rigid twisted tetraamine monomers for efficient organic solvent nanofiltration","authors":"Chenlu Liu , Xiaoting Feng , Keming Zhang , Xiaohe Tian , Qingnan Wang , Yanting Tang , Yueyangchao Yu , Tianhe Gu , Rui Zhang , Xiangyu Liu , Shaofei Wang","doi":"10.1016/j.memsci.2025.124085","DOIUrl":"10.1016/j.memsci.2025.124085","url":null,"abstract":"<div><div>Polyamide membranes with rigid twisted structures show excellent permeance and rejection in the field of organic solvent nanofiltration (OSN). However, challenges such as low reactivity, complex synthesis procedures, and high costs persist for certain rigid and twisted monomers, posing obstacles in their synthesis or application processes. To address these challenges, we adopt a low-cost rigid and twisted tetraamine monomer, N,N,N’,N’-tetrakis(4-aminophenyl)-1,4-benzenediamine (TK), for the preparation of polyamide OSN membranes through interfacial polymerization with various acyl chlorides. TK is effectively introduced into the polyamide chain, which involves not only the reactivity of monomers, but also the influence of monomer angle configuration on the formation of chain segments, forming different rigid networks and enabling the active layer to have excellent stability and high porosity. Consequently, the rigid twisted polyamide OSN membranes exhibit a methanol permeance of 13.8 L m<sup>-2</sup> h<sup>-1</sup> bar<sup>-1</sup> and a molecular weight cut-off (MWCO) of 266 Da, outperforming many reported membranes. This work highlights the use of TK as a promising, cost-effective monomer to engineer high-performance OSN membranes with tailored structural features, offering a practical solution for enhanced organic solvent separation processes.</div></div>","PeriodicalId":368,"journal":{"name":"Journal of Membrane Science","volume":"726 ","pages":"Article 124085"},"PeriodicalIF":8.4,"publicationDate":"2025-04-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143791504","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-04-07DOI: 10.1016/j.memsci.2025.124080
Daehun Kim , Mi-Hee Ryu , Ahrumi Park , Joo-Eon Kim , Seong-Joong Kim , YongSung Kwon , Jungkyu Choi , Jaesung Park
Herein, we present an approach for adjusting the pore structure of carbon molecular sieve (CMS) membranes by controlling UV irradiation on polyimide (PI) precursors. CMS dense membranes were fabricated by pyrolyzing UV-crosslinkable PIs synthesized from 4,4′-(hexafluoroisopropylidene)diphthalic anhydride (6FDA), 3,3′,4,4′-benzophenone tetracarboxylic dianhydride (BTDA), and 2,4-diamino mesitylene (DAM). Increasing UV irradiation time enhanced molecular sieving performance while decreasing gas permeability. At the highest UV irradiation time of 40 min, the gas selectivities for H2/CH4 and CO2/CH4 improved 3-fold and 2-fold, respectively. Meanwhile, H2 and CO2 permeabilities decreased by ∼9 % and ∼30 % relative to the pristine CMS membrane, both deviating notably from the upper bound slope trends. Gas diffusivity and pore size distribution analyses suggested that these improvements stemmed from a reduction in larger ultramicropores. Furthermore, a prolonged CO2/CH4 mixed-gas permeation test (170 days) showed that pre-crosslinked CMS membranes demonstrated enhanced resistance to physical aging. After the aging period, the pre-crosslinked CMS membranes showed slightly higher mixed-gas CO2 permeability and ∼2 times higher mixed-gas CO2/CH4 selectivity than pristine CMS. This study introduces a novel method for tuning the CMS microstructure to produce more selective and aging-resistant carbon membranes.
{"title":"Carbon molecular sieve membranes derived from UV-irradiated polyimides for enhanced molecular separation and physical aging resistance","authors":"Daehun Kim , Mi-Hee Ryu , Ahrumi Park , Joo-Eon Kim , Seong-Joong Kim , YongSung Kwon , Jungkyu Choi , Jaesung Park","doi":"10.1016/j.memsci.2025.124080","DOIUrl":"10.1016/j.memsci.2025.124080","url":null,"abstract":"<div><div>Herein, we present an approach for adjusting the pore structure of carbon molecular sieve (CMS) membranes by controlling UV irradiation on polyimide (PI) precursors. CMS dense membranes were fabricated by pyrolyzing UV-crosslinkable PIs synthesized from 4,4′-(hexafluoroisopropylidene)diphthalic anhydride (6FDA), 3,3′,4,4′-benzophenone tetracarboxylic dianhydride (BTDA), and 2,4-diamino mesitylene (DAM). Increasing UV irradiation time enhanced molecular sieving performance while decreasing gas permeability. At the highest UV irradiation time of 40 min, the gas selectivities for H<sub>2</sub>/CH<sub>4</sub> and CO<sub>2</sub>/CH<sub>4</sub> improved 3-fold and 2-fold, respectively. Meanwhile, H<sub>2</sub> and CO<sub>2</sub> permeabilities decreased by ∼9 % and ∼30 % relative to the pristine CMS membrane, both deviating notably from the upper bound slope trends. Gas diffusivity and pore size distribution analyses suggested that these improvements stemmed from a reduction in larger ultramicropores. Furthermore, a prolonged CO<sub>2</sub>/CH<sub>4</sub> mixed-gas permeation test (170 days) showed that pre-crosslinked CMS membranes demonstrated enhanced resistance to physical aging. After the aging period, the pre-crosslinked CMS membranes showed slightly higher mixed-gas CO<sub>2</sub> permeability and ∼2 times higher mixed-gas CO<sub>2</sub>/CH<sub>4</sub> selectivity than pristine CMS. This study introduces a novel method for tuning the CMS microstructure to produce more selective and aging-resistant carbon membranes.</div></div>","PeriodicalId":368,"journal":{"name":"Journal of Membrane Science","volume":"727 ","pages":"Article 124080"},"PeriodicalIF":8.4,"publicationDate":"2025-04-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143825882","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-04-07DOI: 10.1016/j.memsci.2025.124086
Stef Depuydt , María Laura Bosko , Toon Eerdekens , Willem Van Leuven , Elena Brozzi , Petric Marc Ruya , Bart Van der Bruggen
One of the major drawbacks in the fabrication of cation exchange membranes (CEMs) is the reliance on non-sustainable, harmful and toxic solvents. Until recently, dimethyl sulfoxide (DMSO) was the only green solvent reported for the fabrication of CEMs. Herein, we explore the viability of seven alternative green solvents for the synthesis of a sulfonated PEEK-based (sPEEK) CEM crosslinked with α,α′-dichloro-p-xylene (DCX), namely: DMSO, Tamisolve NxG, Rhodiasolv® PolarClean, Cyrene™, acetyl triethyl citrate, acetyl tributyl citrate and γ-valerolactone. Based on Hansen solubility analysis, and upon preliminary testing, only Tamisolve NxG and DMSO were deemed suitable for CEM fabrication. Several membranes were therefore synthesized by using either Tamisolve NxG, DMSO, or a blend of the two solvents, and subsequently tested for ion conductivity and methanol rejection. The variation of the solvent had a significant impact on the membrane performance. The membrane fabricated with DMSO as the sole solvent but without DCX, resulted in a non-crosslinked sPEEK structure. In this case, the sPEEK polymer chains tend to crystallize upon solvent evaporation, reducing the methanol crossover. However, using DMSO as the sole solvent in combination with the crosslinker resulted in a CEM with a too high electrical resistance due to the high degree of crosslinking together with the crystalline regions formed after evaporation. The use of Tamisolve NxG, instead, inhibited the crosslinking, and was therefore blended with DMSO to optimize the crosslinking degree. The solvent blend resulted in crosslinked sPEEK/DCX-10/90 % having higher electrical conductivity and methanol rejection than Nafion 117, respectively, 2.06∗10−3 vs. 2.8∗10−3/min and 0.036 vs. 0.089 Ω.
{"title":"Utilizing green solvents to synthesize high performance crosslinked sulfonated PEEK cation exchange membranes","authors":"Stef Depuydt , María Laura Bosko , Toon Eerdekens , Willem Van Leuven , Elena Brozzi , Petric Marc Ruya , Bart Van der Bruggen","doi":"10.1016/j.memsci.2025.124086","DOIUrl":"10.1016/j.memsci.2025.124086","url":null,"abstract":"<div><div>One of the major drawbacks in the fabrication of cation exchange membranes (CEMs) is the reliance on non-sustainable, harmful and toxic solvents. Until recently, dimethyl sulfoxide (DMSO) was the only green solvent reported for the fabrication of CEMs. Herein, we explore the viability of seven alternative green solvents for the synthesis of a sulfonated PEEK-based (sPEEK) CEM crosslinked with α,α′-dichloro-p-xylene (DCX), namely: DMSO, Tamisolve NxG, Rhodiasolv® PolarClean, Cyrene™, acetyl triethyl citrate, acetyl tributyl citrate and γ-valerolactone. Based on Hansen solubility analysis, and upon preliminary testing, only Tamisolve NxG and DMSO were deemed suitable for CEM fabrication. Several membranes were therefore synthesized by using either Tamisolve NxG, DMSO, or a blend of the two solvents, and subsequently tested for ion conductivity and methanol rejection. The variation of the solvent had a significant impact on the membrane performance. The membrane fabricated with DMSO as the sole solvent but without DCX, resulted in a non-crosslinked sPEEK structure. In this case, the sPEEK polymer chains tend to crystallize upon solvent evaporation, reducing the methanol crossover. However, using DMSO as the sole solvent in combination with the crosslinker resulted in a CEM with a too high electrical resistance due to the high degree of crosslinking together with the crystalline regions formed after evaporation. The use of Tamisolve NxG, instead, inhibited the crosslinking, and was therefore blended with DMSO to optimize the crosslinking degree. The solvent blend resulted in crosslinked sPEEK/DCX-10/90 % having higher electrical conductivity and methanol rejection than Nafion 117, respectively, 2.06∗10<sup>−3</sup> vs. 2.8∗10<sup>−3</sup>/min and 0.036 vs. 0.089 Ω.</div></div>","PeriodicalId":368,"journal":{"name":"Journal of Membrane Science","volume":"727 ","pages":"Article 124086"},"PeriodicalIF":8.4,"publicationDate":"2025-04-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143820854","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Surface segregation as a simple and efficient method for in situ membrane surface modification, has distinct advantages in constructing antifouling membranes. In this study, two chitosan derivatives, carboxymethyl chitosan (CMC) and chitosan quaternary ammonium salt (HACC), are selected as surface modifiers to fabricate antifouling poly (ether sulfone) (PES) membrane for oil-water filtration. The addition of CMC and HACC can regulate the phase inversion process to acquire membranes with high porosity. During the phase inversion process, CMC and HACC can in situ crosslink the polyvinylpyrrolidone (PVP) segregation agent by hydrogen bonds at the water-polymer interface, constructing a hydrophilic and underwater superoleophobic modification layer on the membrane surface. Specifically, the CMC-modified membrane exhibits enhanced water permeance from 339 to 635 Lm-2h-1bar-1 and antifouling performance with 98% flux recovery and 7% total flux decline. Furthermore, the membrane shows satisfying long-term performance stability in industrial oily wastewater treatment with the permeance maintained above 400 Lm-2h-1bar-1 within 10-hour continuous filtration. The study provides a facile strategy to in situ fabrication of oil-water separation membranes with excellent antifouling performance, which displays application potential in practical oily wastewater treatment.
{"title":"Antifouling membranes modified via chitosan derivatives for efficient oil-water separation","authors":"Lijuan Cheng , Xiaolong Xu , Yurong Jiang , Shiyu Zhang , Kai Xu , Hui Wang , Xianjuan Zhang , Runnan Zhang , Zhongyi Jiang","doi":"10.1016/j.memsci.2025.124082","DOIUrl":"10.1016/j.memsci.2025.124082","url":null,"abstract":"<div><div>Surface segregation as a simple and efficient method for <em>in situ</em> membrane surface modification, has distinct advantages in constructing antifouling membranes. In this study, two chitosan derivatives, carboxymethyl chitosan (CMC) and chitosan quaternary ammonium salt (HACC), are selected as surface modifiers to fabricate antifouling poly (ether sulfone) (PES) membrane for oil-water filtration. The addition of CMC and HACC can regulate the phase inversion process to acquire membranes with high porosity. During the phase inversion process, CMC and HACC can <em>in situ</em> crosslink the polyvinylpyrrolidone (PVP) segregation agent by hydrogen bonds at the water-polymer interface, constructing a hydrophilic and underwater superoleophobic modification layer on the membrane surface. Specifically, the CMC-modified membrane exhibits enhanced water permeance from 339 to 635 Lm<sup>-2</sup>h<sup>-1</sup>bar<sup>-1</sup> and antifouling performance with 98% flux recovery and 7% total flux decline. Furthermore, the membrane shows satisfying long-term performance stability in industrial oily wastewater treatment with the permeance maintained above 400 Lm<sup>-2</sup>h<sup>-1</sup>bar<sup>-1</sup> within 10-hour continuous filtration. The study provides a facile strategy to <em>in situ</em> fabrication of oil-water separation membranes with excellent antifouling performance, which displays application potential in practical oily wastewater treatment.</div></div>","PeriodicalId":368,"journal":{"name":"Journal of Membrane Science","volume":"727 ","pages":"Article 124082"},"PeriodicalIF":8.4,"publicationDate":"2025-04-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143820766","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-04-07DOI: 10.1016/j.memsci.2025.124083
Xiaolong He , Xueyin Lu , Jiajun Xie , Ze-xian Low , Shasha Feng , Yutang Kang , Dong Zou , Peng Sun , Zhaoxiang Zhong , Weihong Xing
Carbon nanofiber membranes (CNFMs) have significant applications in lithium batteries, flexible electronics, sensing, and wave absorption, etc. Their high electrical conductivity, good thermal stability and high specific surface area also render them promising for multifunctional air purification. However, the poor mechanical strength of carbon nanofiber membranes seriously restricts their large-scale application. In this work, a dual-scale defect control strategy is proposed to enhance the mechanical properties and air purification performance of CNFM, which refers to repairing graphite carbon defects on the molecular scale and constructing more micropore defects on the nano scale of the carbon nanofibers. Polyvinylpyrrolidone (PVP) increases the ratio of graphitic carbon and graphitic nitrogen, and the repair of graphite carbon defects results in a higher tensile strength of CNFM. The tensile strength increases from 0.42 to 8.44 MPa, with an increase of 1910 %. Terephthalic acid (TPA) constructs more microporous structures through sublimation to increase micropore defects, thus increasing the elongation at break and flexibility. The Young's modulus decreases from 389 MPa to 89 MPa with a decrease of 81.4 %. The prepared CNFM has a specific surface area of 630 m2 g−1. The PM0.3 filtration efficiency, pressure drop, and quality factor are 99.53 %, 33.3 Pa, and 0.161 Pa-1, respectively. The static adsorption capacity for toluene and formaldehyde is 228.0 mg g−1 and 390.9 mg g−1, respectively. This work provides clear insights into improving the mechanical properties of CNFM and its multifunctional air purification application.
{"title":"Mechanical and functional enhancement of carbon nanofiber membranes via dual-scale defect control strategy for air purification","authors":"Xiaolong He , Xueyin Lu , Jiajun Xie , Ze-xian Low , Shasha Feng , Yutang Kang , Dong Zou , Peng Sun , Zhaoxiang Zhong , Weihong Xing","doi":"10.1016/j.memsci.2025.124083","DOIUrl":"10.1016/j.memsci.2025.124083","url":null,"abstract":"<div><div>Carbon nanofiber membranes (CNFMs) have significant applications in lithium batteries, flexible electronics, sensing, and wave absorption, etc. Their high electrical conductivity, good thermal stability and high specific surface area also render them promising for multifunctional air purification. However, the poor mechanical strength of carbon nanofiber membranes seriously restricts their large-scale application. In this work, a dual-scale defect control strategy is proposed to enhance the mechanical properties and air purification performance of CNFM, which refers to repairing graphite carbon defects on the molecular scale and constructing more micropore defects on the nano scale of the carbon nanofibers. Polyvinylpyrrolidone (PVP) increases the ratio of graphitic carbon and graphitic nitrogen, and the repair of graphite carbon defects results in a higher tensile strength of CNFM. The tensile strength increases from 0.42 to 8.44 MPa, with an increase of 1910 %. Terephthalic acid (TPA) constructs more microporous structures through sublimation to increase micropore defects, thus increasing the elongation at break and flexibility. The Young's modulus decreases from 389 MPa to 89 MPa with a decrease of 81.4 %. The prepared CNFM has a specific surface area of 630 m<sup>2</sup> g<sup>−1</sup>. The PM<sub>0.3</sub> filtration efficiency, pressure drop, and quality factor are 99.53 %, 33.3 Pa, and 0.161 Pa<sup>-1</sup>, respectively. The static adsorption capacity for toluene and formaldehyde is 228.0 mg g<sup>−1</sup> and 390.9 mg g<sup>−1</sup>, respectively. This work provides clear insights into improving the mechanical properties of CNFM and its multifunctional air purification application.</div></div>","PeriodicalId":368,"journal":{"name":"Journal of Membrane Science","volume":"727 ","pages":"Article 124083"},"PeriodicalIF":8.4,"publicationDate":"2025-04-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143814870","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-04-07DOI: 10.1016/j.memsci.2025.124079
Jiahua Chen , Qingwen Qin , Jibao Liu , Hui Jia , Jie Wang
In recent years, with the widespread application of membrane separation technology, the influence of the 'air resistance' phenomenon on membrane filtration performance has gained increasing attention. This study investigates the mechanism of 'air resistance' in the formation of membrane fouling. The results show that 'air resistance' not only significantly reduces membrane flux but also increases the 'irreversible resistance' of the membrane, which negatively impacts the long-term stable operation of the membrane.In this study, highly sensitive fibre bragg grating (FBG) sensing technology was used to monitor the vibrational performance of hollow fiber membranes in real-time, confirming the important role of membrane vibration in controlling 'air resistance'. Quantitative analysis showed that the air content in the membrane was reduced by approximately 52.08% after optimizing the vibration parameters.Additionally, a comparative study of membrane surface modification revealed that outer surface modification was more effective than inner surface modification under fouling conditions, with reductions of about 23.64% and 6.89%, respectively.This study demonstrates that the effect of 'air resistance' can be effectively reduced by adjusting operating parameters and membrane modifications, enabling a more accurate assessment of the nature and extent of actual membrane fouling. It lays the foundation for future research on membrane fouling and the development of smarter, more efficient filtration systems, which will improve the economics and sustainability of water and wastewater treatment.
{"title":"The mystery of ‘air resistance’ in submerged hollow fiber membranes: A controllable 'irreversible fouling'","authors":"Jiahua Chen , Qingwen Qin , Jibao Liu , Hui Jia , Jie Wang","doi":"10.1016/j.memsci.2025.124079","DOIUrl":"10.1016/j.memsci.2025.124079","url":null,"abstract":"<div><div>In recent years, with the widespread application of membrane separation technology, the influence of the 'air resistance' phenomenon on membrane filtration performance has gained increasing attention. This study investigates the mechanism of 'air resistance' in the formation of membrane fouling. The results show that 'air resistance' not only significantly reduces membrane flux but also increases the 'irreversible resistance' of the membrane, which negatively impacts the long-term stable operation of the membrane.In this study, highly sensitive fibre bragg grating (FBG) sensing technology was used to monitor the vibrational performance of hollow fiber membranes in real-time, confirming the important role of membrane vibration in controlling 'air resistance'. Quantitative analysis showed that the air content in the membrane was reduced by approximately 52.08% after optimizing the vibration parameters.Additionally, a comparative study of membrane surface modification revealed that outer surface modification was more effective than inner surface modification under fouling conditions, with reductions of about 23.64% and 6.89%, respectively.This study demonstrates that the effect of 'air resistance' can be effectively reduced by adjusting operating parameters and membrane modifications, enabling a more accurate assessment of the nature and extent of actual membrane fouling. It lays the foundation for future research on membrane fouling and the development of smarter, more efficient filtration systems, which will improve the economics and sustainability of water and wastewater treatment.</div></div>","PeriodicalId":368,"journal":{"name":"Journal of Membrane Science","volume":"727 ","pages":"Article 124079"},"PeriodicalIF":8.4,"publicationDate":"2025-04-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143820767","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-04-05DOI: 10.1016/j.memsci.2025.124023
Ian Keen Koo , Meng Nan Chong , K.B. Goh
Water recovery through pressure-driven bilayer thin-film composite (TFC) membranes remains an open problem, with critical uncertainty centered on its driving forces, namely the hydrostatic pressure gradient, yet systematic investigation remains limited. Here, we present a poromechanics framework that explicitly accounts for the distinct mechanical, structural, and transport properties, elucidating the interplay between flow-induced compaction and water transport in a TFC membrane governing the transport upper limit performance. Our approach naturally splits the strain energy into two regions: (i) a linear-response selective layer and (ii) a non-linear supporting one, mechanically capturing the strain-hardening behavior as the compacted support layer transitions into its bulk polymer state. While the hydrostatic pressure distribution in the selective layer merely scales upward with the increasing applied transmembrane pressure, the distribution in the support layer, however, contorts from a zero slope to a linear one and finally to a non-linear slope, demonstrating how the water transport changes to a support layer-controlled system. Overall, we show how a cancellation between permeance and the hydrostatic pressure difference across TFC membranes drives the transition between (i) support layer-controlled and (ii) selective layer-controlled regimes.
{"title":"Gradient or no gradient: Spatial hydrostatic pressure distributions in bilayer thin-film composite membranes","authors":"Ian Keen Koo , Meng Nan Chong , K.B. Goh","doi":"10.1016/j.memsci.2025.124023","DOIUrl":"10.1016/j.memsci.2025.124023","url":null,"abstract":"<div><div>Water recovery through pressure-driven bilayer thin-film composite (TFC) membranes remains an open problem, with critical uncertainty centered on its driving forces, namely the hydrostatic pressure <em>gradient</em>, yet systematic investigation remains limited. Here, we present a poromechanics framework that explicitly accounts for the distinct mechanical, structural, and transport properties, elucidating the interplay between flow-induced compaction and water transport in a TFC membrane governing the transport upper limit performance. Our approach naturally splits the strain energy into two regions: (i) a linear-response selective layer and (ii) a non-linear supporting one, mechanically capturing the strain-hardening behavior as the compacted support layer transitions into its bulk polymer state. While the hydrostatic pressure distribution in the selective layer merely scales upward with the increasing applied transmembrane pressure, the distribution in the support layer, however, contorts from a zero slope to a linear one and finally to a non-linear slope, demonstrating how the water transport changes to a support layer-controlled system. Overall, we show how a cancellation between permeance and the hydrostatic pressure difference across TFC membranes drives the transition between (i) support layer-controlled and (ii) selective layer-controlled regimes.</div></div>","PeriodicalId":368,"journal":{"name":"Journal of Membrane Science","volume":"727 ","pages":"Article 124023"},"PeriodicalIF":8.4,"publicationDate":"2025-04-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143814871","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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