Pub Date : 2025-02-11DOI: 10.1016/j.memsci.2025.123823
Jiaxin Wu , Chencheng Qin , Miao Li , Qian Peng , Xiaoai Guo , Zifang Li , Xingzhong Yuan , Edison Huixiang Ang , Meng Sun , Hou Wang
An urgent need exists for a green and energy-efficient method for ultra-rapid micropollutant removal from wastewater. Exploring the use of membrane-in-electric cavity system for pharmaceutical decomposition on seconds timescale presents a compelling yet novel approach. An effective photocatalytic membrane with interconnected inner cavities, composed of TFPT-TAPT-COF and NH2–Ti3C2Tx (NTCM), was synthesized using 3-aminopropyltriethoxysilane mediated self-assembly method. Theoretical analysis confirms a charge transfer number of approximately 2.7 |e| within the heterojunction, creating strong built-in electric fields within the cavity walls. In single-pass flow-through wastewater treatment, the NTCM membrane achieved up to 95.4 % removal of norfloxacin, with a disappearance rate of 2.45 × 10⁻⁴ mol m−1 s−1, within a residence time of 3.42 s under 70 mW cm−2 light irradiation and a flow rate of 1 mL min−1. This exceptional efficiency is attributed to the complete separation and swift transfer of photoinduced carriers, which significantly amplifies the likelihood of collisions with micropollutants and facilitates their removal within the confined space of the dynamic convective flow, thereby enhancing the overall pollutant degradation process. Additionally, the NTCM membrane's self-oxygenating feature allows it to effectively treat a range of wastewater substrates, including near-neutral wastewater, fulvic acid, and charged ion species. However, carbonate ions significantly inhibit norfloxacin removal. Overall, this study introduces a cost-effective, high-efficiency, and low-energy approach to micropollutant removal in wastewater treatment.
{"title":"Electric cavity-enhanced catalytic membranes for micropollutant removal in wastewater","authors":"Jiaxin Wu , Chencheng Qin , Miao Li , Qian Peng , Xiaoai Guo , Zifang Li , Xingzhong Yuan , Edison Huixiang Ang , Meng Sun , Hou Wang","doi":"10.1016/j.memsci.2025.123823","DOIUrl":"10.1016/j.memsci.2025.123823","url":null,"abstract":"<div><div>An urgent need exists for a green and energy-efficient method for ultra-rapid micropollutant removal from wastewater. Exploring the use of membrane-in-electric cavity system for pharmaceutical decomposition on seconds timescale presents a compelling yet novel approach. An effective photocatalytic membrane with interconnected inner cavities, composed of TFPT-TAPT-COF and NH<sub>2</sub>–Ti<sub>3</sub>C<sub>2</sub>T<sub>x</sub> (NTCM), was synthesized using 3-aminopropyltriethoxysilane mediated self-assembly method. Theoretical analysis confirms a charge transfer number of approximately 2.7 |e| within the heterojunction, creating strong built-in electric fields within the cavity walls. In single-pass flow-through wastewater treatment, the NTCM membrane achieved up to 95.4 % removal of norfloxacin, with a disappearance rate of 2.45 × 10⁻⁴ mol m<sup>−1</sup> s<sup>−1</sup>, within a residence time of 3.42 s under 70 mW cm<sup>−2</sup> light irradiation and a flow rate of 1 mL min<sup>−1</sup>. This exceptional efficiency is attributed to the complete separation and swift transfer of photoinduced carriers, which significantly amplifies the likelihood of collisions with micropollutants and facilitates their removal within the confined space of the dynamic convective flow, thereby enhancing the overall pollutant degradation process. Additionally, the NTCM membrane's self-oxygenating feature allows it to effectively treat a range of wastewater substrates, including near-neutral wastewater, fulvic acid, and charged ion species. However, carbonate ions significantly inhibit norfloxacin removal. Overall, this study introduces a cost-effective, high-efficiency, and low-energy approach to micropollutant removal in wastewater treatment.</div></div>","PeriodicalId":368,"journal":{"name":"Journal of Membrane Science","volume":"721 ","pages":"Article 123823"},"PeriodicalIF":8.4,"publicationDate":"2025-02-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143419378","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 : 2025-02-11DOI: 10.1016/j.memsci.2025.123834
Yunhao Li , Wu Kuang , Haijun Yu , Dandan Liu , Yanfang Liu , Guodong Kang , Xinmiao Liang , Yiming Cao
Efficient separation of monovalent/multivalent cations and anions is essential for optimizing lithium extraction from Salt-Lake to simplify production processes and reduces costs. Nevertheless, the conventional nanofiltration membranes with specific charges can only separate either cations or anions. To overcome this limitation, a novel strategy is proposed for fabricating nanofiltration membranes with “negative-positive-negative” sandwich-like mixed charge configuration. Herein, two aqueous monomers (phenylbiguanide and polyethyleneimine) with significantly different diffusion rates are employed to react with trimesoyl chloride to form a nascent polyamide layer via interfacial polymerization. Subsequently, phenylbiguanide that preferentially diffuses to top surface of nascent membrane and unreacted amine groups from polyethyleneimine are used to react with m-phenylenedisulfonyl chloride to form a polysulfonamide/polyamide functional layer. The unreacted sulfonyl chloride groups and trimesoyl chloride near aqueous phase could hydrolyzes more easily, producing negatively charged sulfonic acid and carboxyl groups on the top and bottom. Meanwhile, the main part of polyamide layer is positively charged attributed to numerous unreacted amine groups. The “negative-positive-negative” sandwich-like configuration was proven using TOF-SIMS. The fabricated membrane exhibited a selectivity of 57.22 for MgCl2/LiCl and 30.61 for Na2SO4/NaCl. Furthermore, Mg2+/Li+ selectivity of 57.34 was achived for the mixed salt solution (Mg2+/Li+ = 45), showing good application potential in lithium extraction.
{"title":"Nanofiltration membranes with sandwich-like mixed charge layers for high-efficiency Mg2+/Li+ separation","authors":"Yunhao Li , Wu Kuang , Haijun Yu , Dandan Liu , Yanfang Liu , Guodong Kang , Xinmiao Liang , Yiming Cao","doi":"10.1016/j.memsci.2025.123834","DOIUrl":"10.1016/j.memsci.2025.123834","url":null,"abstract":"<div><div>Efficient separation of monovalent/multivalent cations and anions is essential for optimizing lithium extraction from Salt-Lake to simplify production processes and reduces costs. Nevertheless, the conventional nanofiltration membranes with specific charges can only separate either cations or anions. To overcome this limitation, a novel strategy is proposed for fabricating nanofiltration membranes with “negative-positive-negative” sandwich-like mixed charge configuration. Herein, two aqueous monomers (phenylbiguanide and polyethyleneimine) with significantly different diffusion rates are employed to react with trimesoyl chloride to form a nascent polyamide layer via interfacial polymerization. Subsequently, phenylbiguanide that preferentially diffuses to top surface of nascent membrane and unreacted amine groups from polyethyleneimine are used to react with <em>m</em>-phenylenedisulfonyl chloride to form a polysulfonamide/polyamide functional layer. The unreacted sulfonyl chloride groups and trimesoyl chloride near aqueous phase could hydrolyzes more easily, producing negatively charged sulfonic acid and carboxyl groups on the top and bottom. Meanwhile, the main part of polyamide layer is positively charged attributed to numerous unreacted amine groups. The “negative-positive-negative” sandwich-like configuration was proven using TOF-SIMS. The fabricated membrane exhibited a selectivity of 57.22 for MgCl<sub>2</sub>/LiCl and 30.61 for Na<sub>2</sub>SO<sub>4</sub>/NaCl. Furthermore, Mg<sup>2+</sup>/Li<sup>+</sup> selectivity of 57.34 was achived for the mixed salt solution (Mg<sup>2+</sup>/Li<sup>+</sup> = 45), showing good application potential in lithium extraction.</div></div>","PeriodicalId":368,"journal":{"name":"Journal of Membrane Science","volume":"722 ","pages":"Article 123834"},"PeriodicalIF":8.4,"publicationDate":"2025-02-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143437229","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 : 2025-02-11DOI: 10.1016/j.memsci.2025.123838
Chanhyuk Kang , Yeji Moon , Joo Eon Kim , Hyojin Kim , Jinhan Cho , Jinkee Hong , Jaesung Park , Byoung Gak Kim
Carbon dioxide (CO2), a major greenhouse gas, significantly contributes to global warming and negatively affects ecosystems. This necessitates the development of high-performance materials for CO2 removal. Mixed-matrix membranes (MMMs) incorporating metal-organic frameworks (MOFs) are effective for CO₂ separation, but the poor interfacial compatibility between the polymer and filler often reduces membrane performance. In this study, the interfacial issue in MMMs was addressed by surface modification of ZIF-8 with polymers of intrinsic microporosity (PIM-1) using the non-solvent induced surface deposition method. The PIM-1 polymer on the ZIF-8 surface has a high surface area, which prevents pore blockage and overcomes the interfacial issue with the polymer matrix. The effect was studied using Pebax-1657 as a host polymer matrix. At 20 % loading, MMMs with surface-modified ZIF-8@PIM-1 exhibited enhanced CO₂/N₂ and CO₂/CH₄ selectivities, increasing from 44.4 to 15.1 to 45.6 and 18.8, respectively, compared to those of MMMs with unmodified ZIF-8. In addition, the CO₂ permeability increased by about 40 %, from 71 barrer to 105 barrer, compared to that of pure Pebax-1657. This study demonstrates that simple surface modification with PIM-1 can effectively address the interfacial issues between the polymer matrix and MOF in MMMs.
{"title":"Enhanced CO₂ separation performance of mixed-matrix membranes through PIM-1 based surface engineering using non-solvent induced surface deposition","authors":"Chanhyuk Kang , Yeji Moon , Joo Eon Kim , Hyojin Kim , Jinhan Cho , Jinkee Hong , Jaesung Park , Byoung Gak Kim","doi":"10.1016/j.memsci.2025.123838","DOIUrl":"10.1016/j.memsci.2025.123838","url":null,"abstract":"<div><div>Carbon dioxide (CO<sub>2</sub>), a major greenhouse gas, significantly contributes to global warming and negatively affects ecosystems. This necessitates the development of high-performance materials for CO<sub>2</sub> removal. Mixed-matrix membranes (MMMs) incorporating metal-organic frameworks (MOFs) are effective for CO₂ separation, but the poor interfacial compatibility between the polymer and filler often reduces membrane performance. In this study, the interfacial issue in MMMs was addressed by surface modification of ZIF-8 with polymers of intrinsic microporosity (PIM-1) using the non-solvent induced surface deposition method. The PIM-1 polymer on the ZIF-8 surface has a high surface area, which prevents pore blockage and overcomes the interfacial issue with the polymer matrix. The effect was studied using Pebax-1657 as a host polymer matrix. At 20 % loading, MMMs with surface-modified ZIF-8@PIM-1 exhibited enhanced CO₂/N₂ and CO₂/CH₄ selectivities, increasing from 44.4 to 15.1 to 45.6 and 18.8, respectively, compared to those of MMMs with unmodified ZIF-8. In addition, the CO₂ permeability increased by about 40 %, from 71 barrer to 105 barrer, compared to that of pure Pebax-1657. This study demonstrates that simple surface modification with PIM-1 can effectively address the interfacial issues between the polymer matrix and MOF in MMMs.</div></div>","PeriodicalId":368,"journal":{"name":"Journal of Membrane Science","volume":"721 ","pages":"Article 123838"},"PeriodicalIF":8.4,"publicationDate":"2025-02-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143419252","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 : 2025-02-11DOI: 10.1016/j.memsci.2025.123839
Vasudev Tangry, William Haddad, Ali Behboudi, Andrew L. Zydney
Forward osmosis (FO) has primarily been explored for applications in water desalination. While FO has also shown potential in concentrating dairy products, little to no attention has been paid to its potential in concentrating biotherapeutics, particularly to the very high concentrations needed for many monoclonal antibody products that are delivered by subcutaneous injection. This study demonstrates the feasibility of using FO as an alternative to ultrafiltration (UF) to achieve highly concentrated protein formulations using human Immunoglobin G (hIgG) as a model protein. The permeate flux in FO, using 1 M NaCl as the draw solution, decreased with increasing hIgG concentration due primarily to concentration polarization effects that are strongly influenced by the increase in feed viscosity for the concentrated hIgG solution. The importance of the hIgG viscosity on the FO performance was demonstrated by performing experiments with concentrated polyethylene glycol solutions and through mathematical modeling that accounts for the effects of both external and internal concentration polarization on FO performance. Batch concentration experiments with FO achieved final hIgG concentrations greater than 290 g/L compared to a maximum achievable concentration in UF of approximately 150 g/L. These results clearly demonstrate the potential of using FO, with high osmotic pressure draw solutions, to achieve highly concentrated formulations of therapeutic proteins that are beyond the capability of current UF processes.
{"title":"The application of forward osmosis for producing highly concentrated biotherapeutics","authors":"Vasudev Tangry, William Haddad, Ali Behboudi, Andrew L. Zydney","doi":"10.1016/j.memsci.2025.123839","DOIUrl":"10.1016/j.memsci.2025.123839","url":null,"abstract":"<div><div>Forward osmosis (FO) has primarily been explored for applications in water desalination. While FO has also shown potential in concentrating dairy products, little to no attention has been paid to its potential in concentrating biotherapeutics, particularly to the very high concentrations needed for many monoclonal antibody products that are delivered by subcutaneous injection. This study demonstrates the feasibility of using FO as an alternative to ultrafiltration (UF) to achieve highly concentrated protein formulations using human Immunoglobin G (hIgG) as a model protein. The permeate flux in FO, using 1 M NaCl as the draw solution, decreased with increasing hIgG concentration due primarily to concentration polarization effects that are strongly influenced by the increase in feed viscosity for the concentrated hIgG solution. The importance of the hIgG viscosity on the FO performance was demonstrated by performing experiments with concentrated polyethylene glycol solutions and through mathematical modeling that accounts for the effects of both external and internal concentration polarization on FO performance. Batch concentration experiments with FO achieved final hIgG concentrations greater than 290 g/L compared to a maximum achievable concentration in UF of approximately 150 g/L. These results clearly demonstrate the potential of using FO, with high osmotic pressure draw solutions, to achieve highly concentrated formulations of therapeutic proteins that are beyond the capability of current UF processes.</div></div>","PeriodicalId":368,"journal":{"name":"Journal of Membrane Science","volume":"721 ","pages":"Article 123839"},"PeriodicalIF":8.4,"publicationDate":"2025-02-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143419283","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 : 2025-02-11DOI: 10.1016/j.memsci.2025.123825
Ryan A. Johnson, Zoe Reddecliff, Karim El Hajj Sleiman, Joshua D. Moon
A new synthetic strategy to post-functionalize PEGDA membranes using active ester click chemistry was used to study the effects of Lewis base ligand grafting density and basicity on facilitated CO2 transport and separation. Increasing imidazole ligand content from 0 mol% to 60 mol% causes both CO2 and N2 permeabilities to drop by 90+% due to a decrease in gas diffusivities. These diffusivities decrease due to increased chain stiffness from the substitution of flexible PEG groups with stiffer acrylamides. Increasing Lewis basicity of grafted ligands appears to hinder CO2 diffusion due to stronger interactions between the base and CO2 resulting in a 60 % decrease in permeability. This decrease in permeability is accompanied by apparent CO2 chemisorption in piperazine (secondary amine) containing samples and a simultaneous decrease in CO2 diffusion likely due to immobilization of some CO2 as carbamate. These findings allow for better understanding of how nitrogenous Lewis base ligands impact CO2 separations in low Tg copolymer membranes.
{"title":"CO2-selective transport in PEGDA facilitated transport membranes post-functionalized using click chemistry","authors":"Ryan A. Johnson, Zoe Reddecliff, Karim El Hajj Sleiman, Joshua D. Moon","doi":"10.1016/j.memsci.2025.123825","DOIUrl":"10.1016/j.memsci.2025.123825","url":null,"abstract":"<div><div>A new synthetic strategy to post-functionalize PEGDA membranes using active ester click chemistry was used to study the effects of Lewis base ligand grafting density and basicity on facilitated CO<sub>2</sub> transport and separation. Increasing imidazole ligand content from 0 mol% to 60 mol% causes both CO<sub>2</sub> and N<sub>2</sub> permeabilities to drop by 90+% due to a decrease in gas diffusivities. These diffusivities decrease due to increased chain stiffness from the substitution of flexible PEG groups with stiffer acrylamides. Increasing Lewis basicity of grafted ligands appears to hinder CO<sub>2</sub> diffusion due to stronger interactions between the base and CO<sub>2</sub> resulting in a 60 % decrease in permeability. This decrease in permeability is accompanied by apparent CO<sub>2</sub> chemisorption in piperazine (secondary amine) containing samples and a simultaneous decrease in CO<sub>2</sub> diffusion likely due to immobilization of some CO<sub>2</sub> as carbamate. These findings allow for better understanding of how nitrogenous Lewis base ligands impact CO<sub>2</sub> separations in low T<sub>g</sub> copolymer membranes.</div></div>","PeriodicalId":368,"journal":{"name":"Journal of Membrane Science","volume":"722 ","pages":"Article 123825"},"PeriodicalIF":8.4,"publicationDate":"2025-02-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143454583","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 : 2025-02-10DOI: 10.1016/j.memsci.2025.123830
Yaran Du , Haoyang Gao , Maliang Zhang , Kunmei Su , Zhenhuan Li
Alkaline water electrolysis (AWE) systems have been the focus of increasing attention in the green energy field due to their zero carbon emissions. The composite membrane, as a critical component of AWE, is typically used to enhance hydrogen production efficiency by incorporating nanofillers. However, over time, the separation of nanofillers can result in gas cross-permeation, thereby increasing operational risks. This study introduces polyethyleneimine (PEI) into the composite membrane, where hydrogen bonds are formed within the membrane, resulting in a composite membrane with a tunable microporous structure. The resulting composite membrane separator exhibited outstanding performance, achieving a maximum bubble point pressure of 3.96 bar and a decreased area resistance of 0.21 Ω cm2. When subjected to a voltage of 2 V, the composite membrane separator achieved a current density of 896 mA cm−2 at 80 °C in 30 wt% KOH, demonstrating excellent stability. Compared with existing advanced composite membranes, this membrane exhibited a notable advantage in terms of electrolytic performance. This study offers crucial insights for advancing the development of high-performance AWE membranes.
碱性水电解（AWE）系统因其零碳排放而成为绿色能源领域日益关注的焦点。复合膜作为 AWE 的重要组成部分，通常通过加入纳米填料来提高制氢效率。然而，随着时间的推移，纳米填料的分离会导致气体交叉渗透，从而增加操作风险。本研究将聚乙烯亚胺（PEI）引入复合膜，在膜内形成氢键，从而形成具有可调微孔结构的复合膜。由此产生的复合膜分离器性能卓越，最大气泡点压力达到 3.96 巴，面积电阻减小到 0.21 Ω cm2。在 30 wt% KOH 溶液中，当电压为 2 V 时，复合膜分离器在 80 °C 下的电流密度达到 896 mA cm-2，表现出卓越的稳定性。与现有的先进复合膜相比，这种膜在电解性能方面具有显著优势。这项研究为推动高性能 AWE 膜的开发提供了重要启示。
{"title":"Tailoring microstructure of polysulfone composite membranes for alkaline water electrolysis","authors":"Yaran Du , Haoyang Gao , Maliang Zhang , Kunmei Su , Zhenhuan Li","doi":"10.1016/j.memsci.2025.123830","DOIUrl":"10.1016/j.memsci.2025.123830","url":null,"abstract":"<div><div>Alkaline water electrolysis (AWE) systems have been the focus of increasing attention in the green energy field due to their zero carbon emissions. The composite membrane, as a critical component of AWE, is typically used to enhance hydrogen production efficiency by incorporating nanofillers. However, over time, the separation of nanofillers can result in gas cross-permeation, thereby increasing operational risks. This study introduces polyethyleneimine (PEI) into the composite membrane, where hydrogen bonds are formed within the membrane, resulting in a composite membrane with a tunable microporous structure. The resulting composite membrane separator exhibited outstanding performance, achieving a maximum bubble point pressure of 3.96 bar and a decreased area resistance of 0.21 Ω cm<sup>2</sup>. When subjected to a voltage of 2 V, the composite membrane separator achieved a current density of 896 mA cm<sup>−2</sup> at 80 °C in 30 wt% KOH, demonstrating excellent stability. Compared with existing advanced composite membranes, this membrane exhibited a notable advantage in terms of electrolytic performance. This study offers crucial insights for advancing the development of high-performance AWE membranes.</div></div>","PeriodicalId":368,"journal":{"name":"Journal of Membrane Science","volume":"721 ","pages":"Article 123830"},"PeriodicalIF":8.4,"publicationDate":"2025-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143419282","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 : 2025-02-10DOI: 10.1016/j.memsci.2025.123837
Turong Shi, Jiachun Feng, Beibei Tang
Amphiphilic block copolymers are widely used as additives in ultrafiltration membranes preparation by nonsolvent-induced phase separation. During membrane-forming process, an increase in coagulation bath temperature (CBT) will accelerate the kinetics of phase inversion and also promote the micellization of amphiphilic block copolymers. Herein, polyethylene oxide-polypropylene oxide-polyethylene oxide, marketed as Pluronic, is utilized as an additive for preparing asymmetric ultrafiltration membranes. Influence of temperature-induced micelle transition behavior of Pluronic on membrane formation and performance is investigated in detail. It is found that when the CBT increases, temperature-induced micelle transition of Pluronic will lead to a dual effect: (1) The decrease in Pluronic diffusion rate results in a reduced diffusion of the solvent interacting with it, thereby slowing down the precipitation kinetics during phase inversion. (2) The decrease in particle size of Pluronic micelles brings about a reduction in the region left by Pluronic micelles extracted from the casting solution, thus decreasing the membrane pore size. The intrinsic characters of Pluronic, including molecular weight, hydrophilic and hydrophobic block ratio and concentration, determine the dual effect of micelle transition. This work provides an in-depth understanding and practical guidance for the preparation of asymmetric membranes with amphiphilic block copolymers as additive systems.
{"title":"Influence of temperature-induced micelle transition behavior of Pluronic additive on asymmetric ultrafiltration membrane formation and performance","authors":"Turong Shi, Jiachun Feng, Beibei Tang","doi":"10.1016/j.memsci.2025.123837","DOIUrl":"10.1016/j.memsci.2025.123837","url":null,"abstract":"<div><div>Amphiphilic block copolymers are widely used as additives in ultrafiltration membranes preparation by nonsolvent-induced phase separation. During membrane-forming process, an increase in coagulation bath temperature (CBT) will accelerate the kinetics of phase inversion and also promote the micellization of amphiphilic block copolymers. Herein, polyethylene oxide-polypropylene oxide-polyethylene oxide, marketed as Pluronic, is utilized as an additive for preparing asymmetric ultrafiltration membranes. Influence of temperature-induced micelle transition behavior of Pluronic on membrane formation and performance is investigated in detail. It is found that when the CBT increases, temperature-induced micelle transition of Pluronic will lead to a dual effect: (1) The decrease in Pluronic diffusion rate results in a reduced diffusion of the solvent interacting with it, thereby slowing down the precipitation kinetics during phase inversion. (2) The decrease in particle size of Pluronic micelles brings about a reduction in the region left by Pluronic micelles extracted from the casting solution, thus decreasing the membrane pore size. The intrinsic characters of Pluronic, including molecular weight, hydrophilic and hydrophobic block ratio and concentration, determine the dual effect of micelle transition. This work provides an in-depth understanding and practical guidance for the preparation of asymmetric membranes with amphiphilic block copolymers as additive systems.</div></div>","PeriodicalId":368,"journal":{"name":"Journal of Membrane Science","volume":"721 ","pages":"Article 123837"},"PeriodicalIF":8.4,"publicationDate":"2025-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143419277","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 : 2025-02-10DOI: 10.1016/j.memsci.2025.123831
Zheng Cao, Boguslaw Kruczek, Jules Thibault
The rapid development of polymeric membranes for gas separation requires an accurate and suitable method for promptly assessing their performance. The time-lag method is one of the most commonly used methods to estimate the permeation parameters (permeability, diffusivity, and solubility) of single gases in membranes. However, a membrane is not evaluated in isolation; it is placed in a permeation cell, which may impact the determination of these parameters. This paper explores the effect of using a porous support disc on estimating the membrane permeation parameters. The impact of a porous disc supporting an ideal membrane was assessed by solving Fick's second law of diffusion. Results clearly show that the membrane thickness, along with the pore size and the porosity of the porous disc, may significantly influence the estimation of the diffusivity and permeability of the membrane using the time-lag method. Interestingly, the observed effect was not dependent on the intrinsic diffusivity of the membrane. The relative diffusivity and relative permeability are strictly a function of the porosity of the porous disc and the ratio of the pore diameter to the membrane thickness. Results can be used to correct the impact of the porous plate and recover the intrinsic membrane properties.
{"title":"Impact of the porous support disc of a gas permeation cell on the estimation of the membrane transport properties","authors":"Zheng Cao, Boguslaw Kruczek, Jules Thibault","doi":"10.1016/j.memsci.2025.123831","DOIUrl":"10.1016/j.memsci.2025.123831","url":null,"abstract":"<div><div>The rapid development of polymeric membranes for gas separation requires an accurate and suitable method for promptly assessing their performance. The time-lag method is one of the most commonly used methods to estimate the permeation parameters (permeability, diffusivity, and solubility) of single gases in membranes. However, a membrane is not evaluated in isolation; it is placed in a permeation cell, which may impact the determination of these parameters. This paper explores the effect of using a porous support disc on estimating the membrane permeation parameters. The impact of a porous disc supporting an ideal membrane was assessed by solving Fick's second law of diffusion. Results clearly show that the membrane thickness, along with the pore size and the porosity of the porous disc, may significantly influence the estimation of the diffusivity and permeability of the membrane using the time-lag method. Interestingly, the observed effect was not dependent on the intrinsic diffusivity of the membrane. The relative diffusivity and relative permeability are strictly a function of the porosity of the porous disc and the ratio of the pore diameter to the membrane thickness. Results can be used to correct the impact of the porous plate and recover the intrinsic membrane properties.</div></div>","PeriodicalId":368,"journal":{"name":"Journal of Membrane Science","volume":"721 ","pages":"Article 123831"},"PeriodicalIF":8.4,"publicationDate":"2025-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143419379","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 : 2025-02-10DOI: 10.1016/j.memsci.2025.123835
Aokun Li , Siyu Liu , Ruilong Li , Jingjing Chen , Chongchong Chen , Jie Zhang , Wenpeng Li , Xiaoli Wu , Jingtao Wang
Ultrathin (<100 nm) and porous membranes exhibit rapid molecule transport due to the high porosity and short transport path. However, molecule transport behaviors in terms of pore size (r) remain unclear. Herein, four kinds of porous MOF membranes with ultrathin thickness (∼20 nm) are prepared on the support layers. The pore sizes of MOF membranes are subtly adjusted (0.66, 0.81, 1.12, and 1.90 nm) by selecting carboxyl ligands with varied benzene-ring numbers. Based on these platforms, we demonstrate that the transport of both polar and non-polar molecules obeys the typical Hagen-Poiseuille model for ultrathin membrane with pore size larger than 1.0 nm. The permeance of solvents obeys (μ, viscosity; k1,1.90 = 126.84 and k1,1.12 = 580.64). In contrast, for the pore size smaller than 1.0 nm, other factors such as molecule polarity and diameter count. Specifically, for the membrane with pore size of 0.81 nm, the transport of polar and non-polar molecules follows the Hagen-Poiseuille model, but with distinct slopes: and , respectively. While for the membrane with pore size of 0.66 nm, new phenomenal equations are respectively proposed to describe the transport of polar and non-polar molecules. The permeance of polar and non-polar solvents obeys and , respectively (R and D represent molecule diameter and dipole moment, respectively). These findings should shed light on the molecule transport mechanism in porous and ultrathin membranes with confined nanochannels.
{"title":"Molecule transport behaviors in ultrathin and porous membranes: The role of pore size","authors":"Aokun Li , Siyu Liu , Ruilong Li , Jingjing Chen , Chongchong Chen , Jie Zhang , Wenpeng Li , Xiaoli Wu , Jingtao Wang","doi":"10.1016/j.memsci.2025.123835","DOIUrl":"10.1016/j.memsci.2025.123835","url":null,"abstract":"<div><div>Ultrathin (<100 nm) and porous membranes exhibit rapid molecule transport due to the high porosity and short transport path. However, molecule transport behaviors in terms of pore size (<em>r</em>) remain unclear. Herein, four kinds of porous MOF membranes with ultrathin thickness (∼20 nm) are prepared on the support layers. The pore sizes of MOF membranes are subtly adjusted (0.66, 0.81, 1.12, and 1.90 nm) by selecting carboxyl ligands with varied benzene-ring numbers. Based on these platforms, we demonstrate that the transport of both polar and non-polar molecules obeys the typical Hagen-Poiseuille model for ultrathin membrane with pore size larger than 1.0 nm. The permeance of solvents obeys <span><math><mrow><mi>P</mi><mo>=</mo><msub><mi>k</mi><mn>1</mn></msub><mfrac><msup><mi>r</mi><mn>4</mn></msup><mi>μ</mi></mfrac></mrow></math></span> (<em>μ</em>, viscosity; <em>k</em><sub><em>1,1.90</em></sub> = 126.84 and <em>k</em><sub><em>1,1.12</em></sub> = 580.64). In contrast, for the pore size smaller than 1.0 nm, other factors such as molecule polarity and diameter count. Specifically, for the membrane with pore size of 0.81 nm, the transport of polar and non-polar molecules follows the Hagen-Poiseuille model, but with distinct slopes: <span><math><mrow><mi>P</mi><mo>=</mo><msub><mi>k</mi><mn>2</mn></msub><mfrac><msup><mi>r</mi><mn>4</mn></msup><mi>μ</mi></mfrac></mrow></math></span> and <span><math><mrow><mi>P</mi><mo>=</mo><msub><mi>k</mi><mn>3</mn></msub><mfrac><msup><mi>r</mi><mn>4</mn></msup><mi>μ</mi></mfrac></mrow></math></span>, respectively. While for the membrane with pore size of 0.66 nm, new phenomenal equations are respectively proposed to describe the transport of polar and non-polar molecules. The permeance of polar and non-polar solvents obeys <span><math><mrow><mi>P</mi><mo>=</mo><msub><mi>k</mi><mn>4</mn></msub><mfrac><msup><mi>r</mi><mn>4</mn></msup><mrow><msup><mi>R</mi><mn>2</mn></msup><mi>D</mi><mi>μ</mi></mrow></mfrac></mrow></math></span> and <span><math><mrow><mi>P</mi><mo>=</mo><msub><mi>k</mi><mn>5</mn></msub><mfrac><msup><mi>r</mi><mn>4</mn></msup><mrow><msup><mi>R</mi><mn>2</mn></msup><mi>μ</mi></mrow></mfrac></mrow></math></span>, respectively (<em>R</em> and <em>D</em> represent molecule diameter and dipole moment, respectively). These findings should shed light on the molecule transport mechanism in porous and ultrathin membranes with confined nanochannels.</div></div>","PeriodicalId":368,"journal":{"name":"Journal of Membrane Science","volume":"721 ","pages":"Article 123835"},"PeriodicalIF":8.4,"publicationDate":"2025-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143395265","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 : 2025-02-10DOI: 10.1016/j.memsci.2025.123828
Wojciech Ogieglo , Tiara Puspasari , Merza Al Karam, Yingge Wang, Xiaofan Hu, Ingo Pinnau
Carbon molecular sieves (CMS) are a promising class of membrane materials that exhibit excellent gas separation properties originating from their well-developed structures containing micropores (<20 Å), ultramicropores (<7 Å) and submicropores (<4 Å). In the first stage of a membrane development process CMS materials are usually characterized in form of thick (50–100 μm), self-standing isotropic membrane films. For practical applications, however, CMS materials need to be converted into thin, selective layers with thicknesses on the order of several micrometers or less. Reduction of the film thickness can often lead to significant differences in the gas separation performance of the CMS materials similar to the well-known deviations from bulk behavior found in glassy polymers (e.g. glass transition temperatures, density, chain dynamics, physical aging rate, etc.). However, despite its practical importance the thickness-dependence of CMS membranes has been rarely studied systematically. Here, we present a detailed study of the gas separation properties of CMS films derived from a promising intrinsically microporous polyimide precursor (6FDA-HTB) over a broad thickness range of 0.55–100 μm, including free standing (10–100 μm) and supported <1 μm samples. This allows us to directly compare the properties of thick, self-standing films with those of thin, supported films representative of practical CMS membranes. Our results indicate a strong but relatively regular reduction of permeability with decreasing film thickness that suggests a similar mechanism of microporosity evolution for thick and thin films. Despite the reduction of permeability, the thin films still possess quite favorable combinations of permeances and selectivities even after 28 days of physical aging, e.g. O2/N2 > 8, O2 permeance ∼20–30 GPU, CO2/CH4 > 100, CO2 permeance ∼150–300 GPU. The presented results are of significant importance for the design of efficient molecularly sieving membranes based on amorphous microporous CMS materials.
{"title":"Broad range thickness dependence of gas separation properties for carbon molecular sieve membranes based on a hydroxyl-functionalized microporous polyimide","authors":"Wojciech Ogieglo , Tiara Puspasari , Merza Al Karam, Yingge Wang, Xiaofan Hu, Ingo Pinnau","doi":"10.1016/j.memsci.2025.123828","DOIUrl":"10.1016/j.memsci.2025.123828","url":null,"abstract":"<div><div>Carbon molecular sieves (CMS) are a promising class of membrane materials that exhibit excellent gas separation properties originating from their well-developed structures containing micropores (<20 Å), ultramicropores (<7 Å) and submicropores (<4 Å). In the first stage of a membrane development process CMS materials are usually characterized in form of thick (50–100 μm), self-standing isotropic membrane films. For practical applications, however, CMS materials need to be converted into thin, selective layers with thicknesses on the order of several micrometers or less. Reduction of the film thickness can often lead to significant differences in the gas separation performance of the CMS materials similar to the well-known deviations from bulk behavior found in glassy polymers (e.g. glass transition temperatures, density, chain dynamics, physical aging rate, etc.). However, despite its practical importance the thickness-dependence of CMS membranes has been rarely studied systematically. Here, we present a detailed study of the gas separation properties of CMS films derived from a promising intrinsically microporous polyimide precursor (6FDA-HTB) over a broad thickness range of 0.55–100 μm, including free standing (10–100 μm) and supported <1 μm samples. This allows us to directly compare the properties of thick, self-standing films with those of thin, supported films representative of practical CMS membranes. Our results indicate a strong but relatively regular reduction of permeability with decreasing film thickness that suggests a similar mechanism of microporosity evolution for thick and thin films. Despite the reduction of permeability, the thin films still possess quite favorable combinations of permeances and selectivities even after 28 days of physical aging, e.g. O<sub>2</sub>/N<sub>2</sub> > 8, O<sub>2</sub> permeance ∼20–30 GPU, CO<sub>2</sub>/CH<sub>4</sub> > 100, CO<sub>2</sub> permeance ∼150–300 GPU. The presented results are of significant importance for the design of efficient molecularly sieving membranes based on amorphous microporous CMS materials.</div></div>","PeriodicalId":368,"journal":{"name":"Journal of Membrane Science","volume":"721 ","pages":"Article 123828"},"PeriodicalIF":8.4,"publicationDate":"2025-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143419279","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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