Pub Date : 2025-02-27DOI: 10.1016/j.memlet.2025.100093
Hyungjoon Ji , Wooyoung Choi , Eunji Choi , Yunseong Ji , Minsu Kim , Hwan-Jin Jeon , Dae Woo Kim
Polycrystalline layers of metal-organic frameworks (MOFs) are effective for fabricating high-performance membranes, particularly for gas separation. However, the chemical degradation of these polycrystalline layers has not been extensively studied, though it is reasonable to anticipate severe degradation under harsh conditions. Accordingly, we investigated the mechanisms of morphological deformation and chemical structure changes in zeolite imidazolate framework (ZIF)-8 films under highly reactive conditions using plasma. ZIF-8 was selectively chosen among various MOFs due to its widespread use in gas separation applications and its relatively stable chemical bonds. The plasma generated various reactive species, such as ions and radicals, to accelerate the degradation of the ZIF-8 layer. We observed that reactive Ar ions preferentially etch Zn over C, and fluorine-containing radicals chemically react with Zn to form covalent bonds. Notably, we found that the degradation of the polycrystalline layer initially begins at the grain boundaries. However, as defects form on the grain surfaces, the degradation progresses more extensively within the grains than at the grain boundaries.
{"title":"Degradation of polycrystalline zeolitic imidazolate framework membrane under reactive plasma conditions","authors":"Hyungjoon Ji , Wooyoung Choi , Eunji Choi , Yunseong Ji , Minsu Kim , Hwan-Jin Jeon , Dae Woo Kim","doi":"10.1016/j.memlet.2025.100093","DOIUrl":"10.1016/j.memlet.2025.100093","url":null,"abstract":"<div><div>Polycrystalline layers of metal-organic frameworks (MOFs) are effective for fabricating high-performance membranes, particularly for gas separation. However, the chemical degradation of these polycrystalline layers has not been extensively studied, though it is reasonable to anticipate severe degradation under harsh conditions. Accordingly, we investigated the mechanisms of morphological deformation and chemical structure changes in zeolite imidazolate framework (ZIF)-8 films under highly reactive conditions using plasma. ZIF-8 was selectively chosen among various MOFs due to its widespread use in gas separation applications and its relatively stable chemical bonds. The plasma generated various reactive species, such as ions and radicals, to accelerate the degradation of the ZIF-8 layer. We observed that reactive Ar ions preferentially etch Zn over C, and fluorine-containing radicals chemically react with Zn to form covalent bonds. Notably, we found that the degradation of the polycrystalline layer initially begins at the grain boundaries. However, as defects form on the grain surfaces, the degradation progresses more extensively within the grains than at the grain boundaries.</div></div>","PeriodicalId":100805,"journal":{"name":"Journal of Membrane Science Letters","volume":"5 1","pages":"Article 100093"},"PeriodicalIF":4.9,"publicationDate":"2025-02-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143552070","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-30DOI: 10.1016/j.memlet.2025.100092
Yuanhui Tang , Yutao Hu , Sisi Wen , Song Lei , Yakai Lin , Li Ding , Haihui Wang
The high purity of Ar is crucial for industrial applications such as steel production, welding, and laboratory use, while the similar physical properties of O2 and Ar make their efficient separation challenging. Existing technologies, such as cryogenic distillation and pressure swing adsorption, are well-established and widely utilized but are hindered by high energy consumption, operational complexity, or limited efficiency. Inspired by the principle that O2 can permeate through the electrolyte as oxygen ions (O2-) in a solid oxide electrolysis cell, for the first time, this study designed and developed an electrochemically-driven tubular inorganic membrane reactor to separate O2/Ar mixtures, achieving high-purity Ar (≥99.99 %). The tubular membrane reactor featured an anode/electrolyte/cathode sandwich structure, offering a compact design particularly suited for gas separation. The reactor employs Ce0.1Gd0.9O2-x (GDC) as the electrolyte, while GDC and Ba0.9Co0.7Fe0.3Nb0.1O3-x are used as the electrode materials. The resulting membrane reactor was compact, defect-free, and capable of producing Ar with a purity of 99.99 %. Additionally, under a constant total current of 0.75 A and an operating temperature of 800 °C, the membrane reactor demonstrated stable performance for over 130 hours, maintaining a Faradaic efficiency exceeding 95 %. This study anticipates that the membrane reactor can serve as an effective and practical solution for separating O2/Ar mixtures, particularly at low O2 partial pressures.
{"title":"Electrochemically-driven solid oxide tubular membrane reactor for efficient separation of oxygen and argon","authors":"Yuanhui Tang , Yutao Hu , Sisi Wen , Song Lei , Yakai Lin , Li Ding , Haihui Wang","doi":"10.1016/j.memlet.2025.100092","DOIUrl":"10.1016/j.memlet.2025.100092","url":null,"abstract":"<div><div>The high purity of Ar is crucial for industrial applications such as steel production, welding, and laboratory use, while the similar physical properties of O<sub>2</sub> and Ar make their efficient separation challenging. Existing technologies, such as cryogenic distillation and pressure swing adsorption, are well-established and widely utilized but are hindered by high energy consumption, operational complexity, or limited efficiency. Inspired by the principle that O<sub>2</sub> can permeate through the electrolyte as oxygen ions (O<sup>2-</sup>) in a solid oxide electrolysis cell, for the first time, this study designed and developed an electrochemically-driven tubular inorganic membrane reactor to separate O<sub>2</sub>/Ar mixtures, achieving high-purity Ar (≥99.99 %). The tubular membrane reactor featured an anode/electrolyte/cathode sandwich structure, offering a compact design particularly suited for gas separation. The reactor employs Ce<sub>0.1</sub>Gd<sub>0.9</sub>O<sub>2-x</sub> (GDC) as the electrolyte, while GDC and Ba<sub>0.9</sub>Co<sub>0.7</sub>Fe<sub>0.3</sub>Nb<sub>0.1</sub>O<sub>3-x</sub> are used as the electrode materials. The resulting membrane reactor was compact, defect-free, and capable of producing Ar with a purity of 99.99 %. Additionally, under a constant total current of 0.75 A and an operating temperature of 800 °C, the membrane reactor demonstrated stable performance for over 130 hours, maintaining a Faradaic efficiency exceeding 95 %. This study anticipates that the membrane reactor can serve as an effective and practical solution for separating O<sub>2</sub>/Ar mixtures, particularly at low O<sub>2</sub> partial pressures.</div></div>","PeriodicalId":100805,"journal":{"name":"Journal of Membrane Science Letters","volume":"5 1","pages":"Article 100092"},"PeriodicalIF":4.9,"publicationDate":"2025-01-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143292745","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-12-21DOI: 10.1016/j.memlet.2024.100091
Mathilde Lafont, Christophe Castel, Romain Privat, Eric Favre
A new process call Membrane Piston is proposed to investigate the possible energy efficiency improvement by combining compression and gas separation under unsteady state. The membrane on the piston-head acts as a permeable moving barrier between the two compartments. The movement of the membrane initiates the compression, triggering the mass transfer. The decreasing amount of substance at high pressure leads to lower work requirement. A model based on mass and energy balances provides the temporal evolution of the parameters. This new concept is presented through an air separation case study, operated in isothermal and non-isothermal modes. Compared to a steady-state classical membrane separation at identical purity in and pressure ratio, this process shows breakthrough energy efficiency improvements, such as 33 to 63 % decrease for 95 to 97 % N2 purity.
{"title":"Membrane gas separations and energy efficiency: Exploring the selective membrane-piston concept","authors":"Mathilde Lafont, Christophe Castel, Romain Privat, Eric Favre","doi":"10.1016/j.memlet.2024.100091","DOIUrl":"10.1016/j.memlet.2024.100091","url":null,"abstract":"<div><div>A new process call Membrane Piston is proposed to investigate the possible energy efficiency improvement by combining compression and gas separation under unsteady state. The membrane on the piston-head acts as a permeable moving barrier between the two compartments. The movement of the membrane initiates the compression, triggering the mass transfer. The decreasing amount of substance at high pressure leads to lower work requirement. A model based on mass and energy balances provides the temporal evolution of the parameters. This new concept is presented through an air separation case study, operated in isothermal and non-isothermal modes. Compared to a steady-state classical membrane separation at identical purity in <span><math><msub><mi>N</mi><mn>2</mn></msub></math></span> and pressure ratio, this process shows breakthrough energy efficiency improvements, such as 33 to 63 % decrease for 95 to 97 % N<sub>2</sub> purity.</div></div>","PeriodicalId":100805,"journal":{"name":"Journal of Membrane Science Letters","volume":"5 1","pages":"Article 100091"},"PeriodicalIF":4.9,"publicationDate":"2024-12-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143127861","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-12-10DOI: 10.1016/j.memlet.2024.100090
Mohammad Allouzi , Mor Avidar , Liat Birnhack , Razi Epsztein , Anthony P. Straub
Understanding the transport mechanisms in salt-rejecting membranes is critical for improving their separation efficiency and selectivity. Examining transmembrane permeation in terms of energy barriers using the Arrhenius or Eyring approach provides valuable insights into molecular transport within the membrane and at the solution-membrane interfaces. Although useful insights have been gained using the energy barriers framework, which is based on measuring permeability at different temperatures, the method can sometimes show counterintuitive and inconsistent results. In this study, we examine methods to improve the reliability of experimentally obtained energy barriers for transport in salt-rejecting membranes. We first compile energy barrier results for the transport of various solutes in loose and tight salt-rejecting membranes, observing data variability across studies and a weak correlation between energy barriers and membrane type. Next, we demonstrate the importance of thermally stabilizing membranes prior to experimentally evaluating energy barriers, showing that membranes equilibrated at high temperatures and tested with descending temperature produce more stable and reliable trends. In addition to thermal stabilization, we identify that comparing energy barrier values based on a similar concentration polarization modulus is critical when analyzing trends between different solutes and membranes. Following these recommendations, we obtain energy barriers for ion permeation that align with the performance of loose and tight salt-rejecting membranes. We conclude by demonstrating consistent and rational energy barrier measurements in two independent laboratories using the principles discussed. Overall, this study provides important guidelines for the experimental quantification of energy barriers for transport in salt-rejecting membranes.
{"title":"Reliable methods to determine experimental energy barriers for transport in salt-rejecting membranes","authors":"Mohammad Allouzi , Mor Avidar , Liat Birnhack , Razi Epsztein , Anthony P. Straub","doi":"10.1016/j.memlet.2024.100090","DOIUrl":"10.1016/j.memlet.2024.100090","url":null,"abstract":"<div><div>Understanding the transport mechanisms in salt-rejecting membranes is critical for improving their separation efficiency and selectivity. Examining transmembrane permeation in terms of energy barriers using the Arrhenius or Eyring approach provides valuable insights into molecular transport within the membrane and at the solution-membrane interfaces. Although useful insights have been gained using the energy barriers framework, which is based on measuring permeability at different temperatures, the method can sometimes show counterintuitive and inconsistent results. In this study, we examine methods to improve the reliability of experimentally obtained energy barriers for transport in salt-rejecting membranes. We first compile energy barrier results for the transport of various solutes in loose and tight salt-rejecting membranes, observing data variability across studies and a weak correlation between energy barriers and membrane type. Next, we demonstrate the importance of thermally stabilizing membranes prior to experimentally evaluating energy barriers, showing that membranes equilibrated at high temperatures and tested with descending temperature produce more stable and reliable trends. In addition to thermal stabilization, we identify that comparing energy barrier values based on a similar concentration polarization modulus is critical when analyzing trends between different solutes and membranes. Following these recommendations, we obtain energy barriers for ion permeation that align with the performance of loose and tight salt-rejecting membranes. We conclude by demonstrating consistent and rational energy barrier measurements in two independent laboratories using the principles discussed. Overall, this study provides important guidelines for the experimental quantification of energy barriers for transport in salt-rejecting membranes.</div></div>","PeriodicalId":100805,"journal":{"name":"Journal of Membrane Science Letters","volume":"5 1","pages":"Article 100090"},"PeriodicalIF":4.9,"publicationDate":"2024-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143093124","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-30DOI: 10.1016/j.memlet.2024.100089
Du Ru Kang , Gi Hyo Sim , Minjoong Kim , Jae Hun Lee , Jong Hak Kim
While nonsolvent-induced phase separation (NIPS) is widely recognized as an established method for creating porous polymer membranes, this study uniquely employs a nonsolvent to produce a dense, nonporous membrane instead. Specifically, the membranes were rapidly fabricated at low temperatures using dimethyl sulfoxide (DMSO), a high-boiling-point solvent, and water as the nonsolvent. We successfully prepared a series of crosslinked poly(quaterphenyl piperidine) (PQP-BM) network membranes with high crosslinking degrees (up to 47.2 %). By combining a hydrophobic extended polyaromatic backbone with a hydrophilic piperidine-based crosslinker, we achieved distinct microphase separation, which enhanced ion transport, dimensional stability, and thermal and mechanical properties compared to the linear uncrosslinked membranes. The optimized AEM exhibited exceptional mechanical strength (tensile strength >63 MPa), high ion conductivity (151.5 mS cm⁻¹ at 80 °C), and excellent alkaline durability. In single-cell water electrolyzer tests, the PQP-BM membrane demonstrated a remarkable current density of 3.99 A cm⁻² at 2.0 V in 1 M KOH at 50 °C, outperforming the commercial FAA-3–50 membrane by 126 %. This study highlights the potential of the energy-efficient NIFF process as a scalable method for producing advanced AEMs for energy conversion applications.
{"title":"Low-temperature rapid fabrication of crosslinked poly(quaterphenyl piperidine) membrane for anion exchange membrane water electrolyzers","authors":"Du Ru Kang , Gi Hyo Sim , Minjoong Kim , Jae Hun Lee , Jong Hak Kim","doi":"10.1016/j.memlet.2024.100089","DOIUrl":"10.1016/j.memlet.2024.100089","url":null,"abstract":"<div><div>While nonsolvent-induced phase separation (NIPS) is widely recognized as an established method for creating porous polymer membranes, this study uniquely employs a nonsolvent to produce a dense, nonporous membrane instead. Specifically, the membranes were rapidly fabricated at low temperatures using dimethyl sulfoxide (DMSO), a high-boiling-point solvent, and water as the nonsolvent. We successfully prepared a series of crosslinked poly(quaterphenyl piperidine) (PQP-BM) network membranes with high crosslinking degrees (up to 47.2 %). By combining a hydrophobic extended polyaromatic backbone with a hydrophilic piperidine-based crosslinker, we achieved distinct microphase separation, which enhanced ion transport, dimensional stability, and thermal and mechanical properties compared to the linear uncrosslinked membranes. The optimized AEM exhibited exceptional mechanical strength (tensile strength >63 MPa), high ion conductivity (151.5 mS cm⁻¹ at 80 °C), and excellent alkaline durability. In single-cell water electrolyzer tests, the PQP-BM membrane demonstrated a remarkable current density of 3.99 A cm⁻² at 2.0 V in 1 M KOH at 50 °C, outperforming the commercial FAA-3–50 membrane by 126 %. This study highlights the potential of the energy-efficient NIFF process as a scalable method for producing advanced AEMs for energy conversion applications.</div></div>","PeriodicalId":100805,"journal":{"name":"Journal of Membrane Science Letters","volume":"5 1","pages":"Article 100089"},"PeriodicalIF":4.9,"publicationDate":"2024-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143093123","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This study explores the development of a thermostable and bio-inert PVDF membrane by grafting poly(acrylamide-r-N-vinylpyrrolidone) (P(AA-r-NVP)) onto a styrene-co-maleic anhydride (SMA)-functionalized PVDF substrate. The fabrication process involved blending SMA into the PVDF matrix followed by vapor-induced phase separation process to form the porous membrane. P(AA-r-NVP) was then grafted onto the membrane through the ring-opening of maleic anhydride groups. Characterization through ATR-FTIR and XPS confirmed successful surface modification. Antifouling performance of the membranes were assessed through bacterial adhesion tests before and after steam sterilization. Before sterilization, SMA3_A3V7 effectively resisted up to 97 % of E. coli adhesion. After steam sterilization, SMA3_A3V7 demonstrated excellent thermal stability, with a minimal 1.25 % increase in bacterial adhesion, compared to a 250 % increase in the unmodified PVDF membrane. These findings feature the effectiveness of utilizing SMA in simplifying the grafting process and the contribution of the thermostable and bio-inert polymer in imparting high-temperature resistance and antifouling resistance to the membrane, enabling versatile applications.
{"title":"Engineering bio-inert and thermostable poly(vinylidene difluoride) membranes by grafting thermal-tolerant copolymers via ring-opening reaction","authors":"Irish Valerie Maggay, Ying-Tzu Chiu, Hao-Tung Lin, Antoine Venault, Yung Chang","doi":"10.1016/j.memlet.2024.100088","DOIUrl":"10.1016/j.memlet.2024.100088","url":null,"abstract":"<div><div>This study explores the development of a thermostable and bio-inert PVDF membrane by grafting poly(acrylamide-<em>r</em>-N-vinylpyrrolidone) (P(AA-<em>r</em>-NVP)) onto a styrene-<em>co</em>-maleic anhydride (SMA)-functionalized PVDF substrate. The fabrication process involved blending SMA into the PVDF matrix followed by vapor-induced phase separation process to form the porous membrane. P(AA-<em>r</em>-NVP) was then grafted onto the membrane through the ring-opening of maleic anhydride groups. Characterization through ATR-FTIR and XPS confirmed successful surface modification. Antifouling performance of the membranes were assessed through bacterial adhesion tests before and after steam sterilization. Before sterilization, SMA3_A3V7 effectively resisted up to 97 % of <em>E. coli</em> adhesion. After steam sterilization, SMA3_A3V7 demonstrated excellent thermal stability, with a minimal 1.25 % increase in bacterial adhesion, compared to a 250 % increase in the unmodified PVDF membrane. These findings feature the effectiveness of utilizing SMA in simplifying the grafting process and the contribution of the thermostable and bio-inert polymer in imparting high-temperature resistance and antifouling resistance to the membrane, enabling versatile applications.</div></div>","PeriodicalId":100805,"journal":{"name":"Journal of Membrane Science Letters","volume":"5 1","pages":"Article 100088"},"PeriodicalIF":4.9,"publicationDate":"2024-11-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143093116","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-28DOI: 10.1016/j.memlet.2024.100087
Jonathan Aubuchon Ouimet, Faraj Al-Badani, Xinhong Liu, Laurianne Lair, Zachary W. Muetzel, Alexander W. Dowling, William A. Phillip
Self-driving laboratories and automated experiments can accelerate the design workflow and decrease errors associated with experiments that characterize membrane transport properties. Within this study, we use 3D printing to design a custom stirred cell that incorporates inline conductivity probes in the retentate and permeate streams. The probes provide a complete trajectory of the salt concentrations as they evolve over the course of an experiment. Here, automated diafiltration experiments are used to characterize the performance of commercial NF90 and NF270 polyamide membranes over a predetermined range of KCl concentrations from 1 to 100 mM. The measurements obtained by the inline conductivity probes are validated using offline post-experiment analyses. Compared to traditional filtration experiments, the probes decrease the amount of time required for an experimentalist to characterize membrane materials by more than 50× and increase the amount of information generated by 100×. Device design principles to address the physical constraints associated with making conductivity measurements in confined volumes are proposed. Overall, the device developed within this study provides a foundation to establish high-throughput, automated membrane characterization techniques.
自动驾驶实验室和自动化实验可以加快设计工作流程，减少与表征膜传输特性的实验相关的误差。在这项研究中，我们使用 3D 打印技术设计了一个定制的搅拌池，在回流液和渗透液中加入了在线电导探针。探针可提供盐浓度在实验过程中演变的完整轨迹。在这里，自动重滤实验用于鉴定商用 NF90 和 NF270 聚酰胺膜在 1 至 100 mM 氯化钾浓度预定范围内的性能。在线电导探头获得的测量结果通过离线实验后分析进行验证。与传统的过滤实验相比，该探头使实验人员表征膜材料所需的时间减少了 50 倍以上，所产生的信息量增加了 100 倍。针对在密闭体积内进行电导率测量的相关物理限制，提出了设备设计原则。总之，本研究开发的设备为建立高通量、自动化的膜表征技术奠定了基础。
{"title":"Automated membrane characterization: In-situ monitoring of the permeate and retentate solutions using a 3D printed permeate probe device","authors":"Jonathan Aubuchon Ouimet, Faraj Al-Badani, Xinhong Liu, Laurianne Lair, Zachary W. Muetzel, Alexander W. Dowling, William A. Phillip","doi":"10.1016/j.memlet.2024.100087","DOIUrl":"10.1016/j.memlet.2024.100087","url":null,"abstract":"<div><div>Self-driving laboratories and automated experiments can accelerate the design workflow and decrease errors associated with experiments that characterize membrane transport properties. Within this study, we use 3D printing to design a custom stirred cell that incorporates inline conductivity probes in the retentate and permeate streams. The probes provide a complete trajectory of the salt concentrations as they evolve over the course of an experiment. Here, automated diafiltration experiments are used to characterize the performance of commercial NF90 and NF270 polyamide membranes over a predetermined range of KCl concentrations from 1 to 100 mM. The measurements obtained by the inline conductivity probes are validated using offline post-experiment analyses. Compared to traditional filtration experiments, the probes decrease the amount of time required for an experimentalist to characterize membrane materials by more than 50× and increase the amount of information generated by 100×. Device design principles to address the physical constraints associated with making conductivity measurements in confined volumes are proposed. Overall, the device developed within this study provides a foundation to establish high-throughput, automated membrane characterization techniques.</div></div>","PeriodicalId":100805,"journal":{"name":"Journal of Membrane Science Letters","volume":"4 2","pages":"Article 100087"},"PeriodicalIF":4.9,"publicationDate":"2024-09-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142417297","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-26DOI: 10.1016/j.memlet.2024.100086
Xinyi Wang , Minhao Xiao , Sungsoon Kim , Jeffrey Zhang , Minju Cha , Anya Dickinson-Cove , Fan Yang , Kenji Lam , Sungju Im , Ziwei Hou , Jishan Wu , Zhiyong Jason Ren , Christos T. Maravelias , Eric M.V. Hoek , David Jassby
Phosphate recovery from wastewater is vital for both environmental sustainability and resource conservation, offering the dual benefit of reducing phosphate pollution while providing a valuable source of this essential nutrient. We previously reported an approach for synthesizing hydrous manganese oxide (HMO) nanoparticles within a polymeric cation-exchange membrane (CEM) to achieve a phosphate-selective mixed-matrix membrane (PhSMMM); however, the phosphate flux was lower than desired. Herein, we demonstrate a next-generation PhSMMM membrane with enhanced phosphate flux and selectivity. Experimental results confirm the successful incorporation of up to 28 wt% HMO nanoparticles into the polymeric CEM. The new PhSMMM exhibits a phosphate flux of 1.57 mmol∙m–2.hr–1 (an 8.5X enhancement), with selectivity over chloride, nitrate, and sulfate ions of 9, 11, and 104, respectively. This significant enhancement in phosphate flux marks a promising advancement in a sustainable solution for phosphate removal and recovery from wastewater.
{"title":"Enhanced phosphate anion flux through single-ion, reverse-selective mixed-matrix cation exchange membrane","authors":"Xinyi Wang , Minhao Xiao , Sungsoon Kim , Jeffrey Zhang , Minju Cha , Anya Dickinson-Cove , Fan Yang , Kenji Lam , Sungju Im , Ziwei Hou , Jishan Wu , Zhiyong Jason Ren , Christos T. Maravelias , Eric M.V. Hoek , David Jassby","doi":"10.1016/j.memlet.2024.100086","DOIUrl":"10.1016/j.memlet.2024.100086","url":null,"abstract":"<div><div>Phosphate recovery from wastewater is vital for both environmental sustainability and resource conservation, offering the dual benefit of reducing phosphate pollution while providing a valuable source of this essential nutrient. We previously reported an approach for synthesizing hydrous manganese oxide (HMO) nanoparticles within a polymeric cation-exchange membrane (CEM) to achieve a phosphate-selective mixed-matrix membrane (PhSMMM); however, the phosphate flux was lower than desired. Herein, we demonstrate a next-generation PhSMMM membrane with enhanced phosphate flux and selectivity. Experimental results confirm the successful incorporation of up to 28 wt% HMO nanoparticles into the polymeric CEM. The new PhSMMM exhibits a phosphate flux of 1.57 mmol∙m<sup>–2.</sup>hr<sup>–1</sup> (an 8.5X enhancement), with selectivity over chloride, nitrate, and sulfate ions of 9, 11, and 104, respectively. This significant enhancement in phosphate flux marks a promising advancement in a sustainable solution for phosphate removal and recovery from wastewater.</div></div>","PeriodicalId":100805,"journal":{"name":"Journal of Membrane Science Letters","volume":"4 2","pages":"Article 100086"},"PeriodicalIF":4.9,"publicationDate":"2024-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142417298","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-19DOI: 10.1016/j.memlet.2024.100085
Masaki Kato , Teruki Ando , Cho Rong Kim , Seiya Yokokura , Hiroki Waizumi , Toshihiro Shimada
Gas separation technology is crucial for addressing environmental issues like CO2 capture to mitigate climate change. While membrane separation is often cited for its efficiency, accurate estimations are scarce. We present estimations based on classical thermodynamics for very lean CO2 composition (400 ppm), revealing rich details in simple systems and deriving guiding principles. Our main conclusion emphasizes the critical necessity of a high membrane separation ratio, and we discuss candidates for achieving this goal.
{"title":"Thermodynamic efficiency of membrane separation of dilute gas: Estimation for CO2 direct air capture application","authors":"Masaki Kato , Teruki Ando , Cho Rong Kim , Seiya Yokokura , Hiroki Waizumi , Toshihiro Shimada","doi":"10.1016/j.memlet.2024.100085","DOIUrl":"10.1016/j.memlet.2024.100085","url":null,"abstract":"<div><div>Gas separation technology is crucial for addressing environmental issues like CO<sub>2</sub> capture to mitigate climate change. While membrane separation is often cited for its efficiency, accurate estimations are scarce. We present estimations based on classical thermodynamics for very lean CO<sub>2</sub> composition (400 ppm), revealing rich details in simple systems and deriving guiding principles. Our main conclusion emphasizes the critical necessity of a high membrane separation ratio, and we discuss candidates for achieving this goal.</div></div>","PeriodicalId":100805,"journal":{"name":"Journal of Membrane Science Letters","volume":"4 2","pages":"Article 100085"},"PeriodicalIF":4.9,"publicationDate":"2024-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142323733","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-07DOI: 10.1016/j.memlet.2024.100084
Viatcheslav Freger , Guy Z. Ramon
The solution-diffusion (SD) model has been instrumental in the advancement of membrane science, due to its simplicity, transparency, and utility in process engineering. However, some doubts have recently been raised, concerning the fundamental validity of SD. These have largely been based on apparent discrepancies between molecular dynamics simulations and several features, deemed inherent to SD, that appeared in early reports — namely, the exact nature of the pressure and concentration distributions within the membrane. Herein, we re-visit the underlying physics of SD in the context of composite membranes, making no a-priori assumptions and, particularly, highlighting the role of polymer thermodynamics and the mechanics of a loaded, swollen film, supported by a porous substrate. The analysis provides a coherent view, linking the solvent concentration profile within the film and the resultant flux-pressure relations with the polymer rigidity and, importantly, the way in which the film is supported. It is shown that, although the flux may generally vary non-linearly with the feed pressure and depend on the film-support geometry, for rigid films – most common in real operations – SD predicts a linear behavior, virtually independent of specific geometry and pressure distribution. Moving forward, we stress the importance and need for further refinements of the SD model, driven by insight from molecular dynamics, thermodynamics and mechanics, while maintaining its applicability to process design.
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