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Yuan KX, Wu Q, Hu K, Liu YL, Wang W, Feng H, Liu Y, Bao X, Ma J. Harnessing Electrochemistry Synergy in Reverse Osmosis: Modulating Ammonium Localized Oxidation and Restricted Transport. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2025; 59:4188-4198. [PMID: 39968933 DOI: 10.1021/acs.est.4c13098] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/20/2025]
Abstract
The unsatisfactory selectivity of reverse osmosis (RO) membranes toward ammonium poses a critical challenge in water safety when reclaiming water from domestic wastewater. Herein, we developed a novel integrated electrochemical-assisted RO (ECRO) system using the electrically treated feed spacer and permeate carrier as electrodes. This system enhanced ammonium removal efficiency significantly while maintaining low energy consumption, increasing from 94.36% at 0 V to 99.91% at 4 V. The improvement was primarily attributed to localized oxidation and restricted transport of ammonium ions. Specifically, the permeate carrier anode facilitated the indirect oxidation of ammonium through active chlorine via the breakpoint chlorination pathway, notably localized on the permeate side to prevent damage to the separation layer of the RO membrane and simultaneously avoid additional chemical additives. Furthermore, the restricted ammonium ion transport was responsible for its improved enthalpic barrier, as evidenced by both experimental investigation and Monte Carlo simulation. This rise in enthalpic barrier was primarily driven by the reverse electric field force across the RO membrane, coupled with the constrained ion migration near the membrane surface and ion diffusion within the membrane. This study offers new insights and a theoretical foundation for the optimization of electrochemistry synergy membrane systems, highlighting the potential for enhancing ammonium removal in wastewater reclamation in a green and low-energy manner.
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Affiliation(s)
- Ke-Xin Yuan
- State Key Laboratory of Urban Water Resources and Environment, Harbin Institute of Technology, Harbin 150090, People's Republic of China
| | - Qinglian Wu
- State Key Laboratory of Urban Water Resources and Environment, Harbin Institute of Technology, Harbin 150090, People's Republic of China
| | - Kai Hu
- State Key Laboratory of Urban Water Resources and Environment, Harbin Institute of Technology, Harbin 150090, People's Republic of China
| | - Yu-Lei Liu
- State Key Laboratory of Urban Water Resources and Environment, Harbin Institute of Technology, Harbin 150090, People's Republic of China
| | - Wei Wang
- State Key Laboratory of Urban Water Resources and Environment, Harbin Institute of Technology, Harbin 150090, People's Republic of China
| | - Haoran Feng
- State Key Laboratory of Urban Water Resources and Environment, Harbin Institute of Technology, Harbin 150090, People's Republic of China
| | - Yi Liu
- State Key Laboratory of Urban Water Resources and Environment, Harbin Institute of Technology, Harbin 150090, People's Republic of China
| | - Xian Bao
- State Key Laboratory of Urban Water Resources and Environment, Harbin Institute of Technology, Harbin 150090, People's Republic of China
| | - Jun Ma
- State Key Laboratory of Urban Water Resources and Environment, Harbin Institute of Technology, Harbin 150090, People's Republic of China
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Shen P, Zhang X, Xu H, Pan B. Substitution-Leaching-Deposition (SLD) Processes Drive Reversible Surface Layer Reconstruction of Metal Oxides for Fluoride Adsorption. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2025; 59:3814-3825. [PMID: 39930573 DOI: 10.1021/acs.est.4c11768] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/26/2025]
Abstract
Surface complexation has long been recognized as the basic mode involved in fluoride adsorption onto metal oxides. However, such general recognition is challenged by the unusual pH dependence observed in fluoride adsorption. Here, we selected hydrated zirconium oxide (HZO) as a representative metal oxide to revisit the fluoride adsorption mechanism. Multiple in situ microscopic analyses and thermodynamic simulations suggest that, unlike the adsorption of other anions that proceed exclusively via substituting protonated terminal hydroxyl (η-OH2+) groups of metal oxides, fluoride can displace both η-OH2+ and protonated bridging hydroxyl (μ-OH+) groups of HZO (i.e., Substitution). This distinctive displacement drives the leaching of Zr from HZO, generating aqueous polyfluorozirconium complexes (i.e., Leaching) which subsequently deposit onto HZO via outer-sphere complexation (i.e., Deposition). The adsorbed polyfluorozirconium gradually converts into a fluorozirconate (Na5Zr2F13) coating, resulting in a surface layer reconstruction of up to 100 nm in depth. The atypical pH dependency of fluoride adsorption can be explained by the processes of Substitution, Leaching, and Deposition (i.e., SLD processes). More attractively, the SLD-driven surface layer reconstruction is reversible in nature, ensuring the constant defluoridation capability of HZO during cyclic adsorption-desorption assays. This study advances our understanding of fluoride adsorption at water-metal oxide interfaces.
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Affiliation(s)
- Pengfei Shen
- State Key Laboratory of Pollution Control and Resource Reuse, School of Environment, Nanjing University, Nanjing 210023, China
| | - Xiaolin Zhang
- State Key Laboratory of Pollution Control and Resource Reuse, School of Environment, Nanjing University, Nanjing 210023, China
- Research Center for Environmental Nanotechnology (ReCENT), Nanjing University, Nanjing 210023, China
| | - Hui Xu
- State Key Laboratory of Pollution Control and Resource Reuse, School of Environment, Nanjing University, Nanjing 210023, China
- Research Center for Environmental Nanotechnology (ReCENT), Nanjing University, Nanjing 210023, China
| | - Bingcai Pan
- State Key Laboratory of Pollution Control and Resource Reuse, School of Environment, Nanjing University, Nanjing 210023, China
- Research Center for Environmental Nanotechnology (ReCENT), Nanjing University, Nanjing 210023, China
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Wu Y, Chen Z, Lu C, Hu C, Qu J. Pulsatile Ion Transport in Nanofiltration Membranes Coupled with Electrically Tunable Pore and Hydroxyl Electrostatic Interactions. ACS NANO 2025; 19:4993-5004. [PMID: 39848794 DOI: 10.1021/acsnano.4c17637] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/25/2025]
Abstract
Pulsatile ion transport facilitates the adjusted transfer of substances, meeting the requirements for the gradient and timed separation of multiple components in membrane processes. Responsive nanofiltration membranes are thus currently receiving widespread attention but face limitations due to their narrow performance adjustment range. Herein, hydroxyl functional groups were introduced into electrically responsive nanofiltration membranes to broaden the adjustment range of separation performance through a combination of pore size sieving and functional group interactions, resulting in a greater change in rejection and flux compared to the original membrane. Membrane pore size is regulated by polypyrrole volume changes and becomes more variable when the cation's hydration radius is smaller. Although the hydroxyl group did not affect the charge transfer or volume change capacity of polypyrrole, it enhanced ion-pore interactions during ion transport, which was particularly pronounced in smaller nanochannels. The size effect of functional group interactions more strongly enhances the transmembrane energy barrier in the reduced state compared with the oxidized state, ultimately resulting in greater modulation of performance. This coupling strategy provides insights into the design of responsive membranes, offering the potential to achieve gradient separation of various solutes.
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Affiliation(s)
- You Wu
- State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Zhibin Chen
- State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Chenghai Lu
- State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Chengzhi Hu
- State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jiuhui Qu
- State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
- University of Chinese Academy of Sciences, Beijing 100049, China
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Li X, Zuo P, Ge X, Yang Z, Xu T. Constructing new-generation ion exchange membranes under confinement regime. Natl Sci Rev 2025; 12:nwae439. [PMID: 39830406 PMCID: PMC11737391 DOI: 10.1093/nsr/nwae439] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2024] [Revised: 09/29/2024] [Accepted: 11/27/2024] [Indexed: 01/22/2025] Open
Abstract
Ion exchange membranes (IEMs) enable fast and selective ion transport and the partition of electrode reactions, playing an important role in the fields of precise ion separation, renewable energy storage and conversion, and clean energy production. Traditional IEMs form ion channels at the nanometer-scale via the assembly of flexible polymeric chains, which are trapped in the permeability/conductivity and selectivity trade-off dilemma due to a high swelling propensity. New-generation IEMs have shown great potential to break this intrinsic limitation by using microporous framework channels for ion transport under a confinement regime. In this Review, we first describe the fundamental principles of ion transport in charged channels from nanometer to sub-nanometer scale. Then, we focus on the construction of new-generation IEMs and highlight the microporous confinement effects from sub-2-nm to sub-1-nm and further to ultra-micropores. The enhanced ion transport properties brought by the intense size sieving and channel interaction are elucidated, and the corresponding applications including lithium separation, flow battery, water electrolysis, and ammonia synthesis are introduced. Finally, we prospect the future development of new-generation IEMs with respect to the intricate microstructure observation, in-situ ion transport visualization, and large-scale membrane fabrication.
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Affiliation(s)
- Xingya Li
- Key Laboratory of Precision and Intelligent Chemistry, School of Chemistry and Materials Science, University of Science and Technology of China, Hefei 230026, China
| | - Peipei Zuo
- Key Laboratory of Precision and Intelligent Chemistry, School of Chemistry and Materials Science, University of Science and Technology of China, Hefei 230026, China
| | - Xiaolin Ge
- Key Laboratory of Precision and Intelligent Chemistry, School of Chemistry and Materials Science, University of Science and Technology of China, Hefei 230026, China
| | - Zhengjin Yang
- Key Laboratory of Precision and Intelligent Chemistry, School of Chemistry and Materials Science, University of Science and Technology of China, Hefei 230026, China
| | - Tongwen Xu
- Key Laboratory of Precision and Intelligent Chemistry, School of Chemistry and Materials Science, University of Science and Technology of China, Hefei 230026, China
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Zheng R, Xu S, Zhong S, Tong X, Yu X, Zhao Y, Chen Y. Enhancing Ion Selectivity of Nanofiltration Membranes via Heterogeneous Charge Distribution. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2024; 58:22818-22828. [PMID: 39671316 DOI: 10.1021/acs.est.4c08841] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2024]
Abstract
Nanofiltration technology holds significant potential for precisely separating monovalent and multivalent ions, such as lithium (Li) and magnesium (Mg) ions, during lithium extraction from salt lakes. This study bridges a crucial gap in understanding the impact of the membrane spatial charge distribution on ion-selective separation. We developed two types of mixed-charge membranes with similar pore sizes but distinct longitudinal and horizontal distributions of oppositely charged domains. The charge-mosaic membrane, synthesized and utilized for ion fractionation for the first time, achieved an exceptional water permeance of 15.4 LMH/bar and a Li/Mg selectivity of 108, outperforming the majority of published reports. Through comprehensive characterization, mathematical modeling, and machine learning methods, we provide evidence that the spatial charge distribution dominantly determines ion selectivity. The charge-mosaic structure excels by substantially promoting ion selectivity through locally enhanced Donnan effects while remaining unaffected by variations in feedwater concentration. Our findings not only demonstrate the applicability of charge-mosaic membranes to precise nanofiltration but also have profound implications for technologies demanding advanced ion selectivity, including those in the sustainable water treatment and energy storage industries.
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Affiliation(s)
- Ruiqi Zheng
- Fujian Key Laboratory of Coastal Pollution Prevention and Control, College of the Environment and Ecology, Xiamen University, Xiamen 361102, China
| | - Shuyi Xu
- Fujian Key Laboratory of Coastal Pollution Prevention and Control, College of the Environment and Ecology, Xiamen University, Xiamen 361102, China
| | - Shifa Zhong
- Department of Environmental Science, Institute of Eco-Chongming, School of Ecological and Environmental Sciences, East China Normal University, Shanghai 200241, China
| | - Xin Tong
- State Key Laboratory of Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Tongji University, Shanghai 200092, China
| | - Xin Yu
- Fujian Key Laboratory of Coastal Pollution Prevention and Control, College of the Environment and Ecology, Xiamen University, Xiamen 361102, China
| | - Yangying Zhao
- Fujian Key Laboratory of Coastal Pollution Prevention and Control, College of the Environment and Ecology, Xiamen University, Xiamen 361102, China
| | - Yongsheng Chen
- School of Civil & Environmental Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
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Wang W, Wang C, Huang R, Hong G, Zhang Y, Zhang X, Shao L. Boosting lithium/magnesium separation performance of selective electrodialysis membranes regulated by enamine reaction. WATER RESEARCH 2024; 268:122729. [PMID: 39531798 DOI: 10.1016/j.watres.2024.122729] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2024] [Revised: 10/08/2024] [Accepted: 10/30/2024] [Indexed: 11/16/2024]
Abstract
Monovalent cation exchange membranes (MCEMs) have progressively played an important role in the field of ion separation. However, according to transition state theory (TST), synchronously tuning the enthalpy barrier (△H) and entropy barrier (△S) for cation transport to improve ion separation performance is challenging. Here, the enamine reaction between the -NH- and -CHO groups is applied to regulate the subsequent Schiff-base reaction between the -CHO and -NH2 groups, which reduces the positive charges of the selective layer but increases the steric hindrance. The increased -T△S (△S term) for cation transport plays an important role in improving Li+/Mg2+ separation performance. The optimal positively-charged glutaraldehyde@piperazine/polyethyleneimine assembled membrane (M-Glu@PIP/PEI) has a perm-selectivity (Li+/Mg2+) of 31.83 with a Li+ flux of 1.87 mol·m-2·h-1, surpassing the Li+/Mg2+ separation performance of state-of-the-art monovalent ion selective membranes (MISMs). Most importantly, the selective electrodialysis (S-ED) process with M-Glu@PIP/PEI can be directly applied to treat simulated salt-lake brines (SLBs), and its superior Li+/Mg2+ separation performance and operational stability enables 74.44 % of the lithium resources with a Li+ purity of 34.02 % to be recovered. This study presents new insights into the design of high-performance MCEMs for energy-efficient resource recovery.
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Affiliation(s)
- Wenguang Wang
- MIIT Key Laboratory of Critical Materials Technology for New Energy Conversion and Storage, State Key Laboratory of Urban Water Resource and Environment, School of Chemistry and Chemical Engineering, Harbin Institute of Technology, Harbin 150001, China; School of Materials Science and Engineering, China University of Petroleum (East China), Qingdao 266580, China
| | - Chao Wang
- MIIT Key Laboratory of Critical Materials Technology for New Energy Conversion and Storage, State Key Laboratory of Urban Water Resource and Environment, School of Chemistry and Chemical Engineering, Harbin Institute of Technology, Harbin 150001, China
| | - Renyao Huang
- Beijing OriginWater Membrane Technology Co., Ltd, Beijing 101400, China
| | - Guanghui Hong
- Center for Analysis, Measurement and Computing, Harbin Institute of Technology, Harbin 150001, China
| | - Yanqiu Zhang
- MIIT Key Laboratory of Critical Materials Technology for New Energy Conversion and Storage, State Key Laboratory of Urban Water Resource and Environment, School of Chemistry and Chemical Engineering, Harbin Institute of Technology, Harbin 150001, China.
| | - Xigui Zhang
- Yangtze Delta Region Institute (Huzhou), University of Electronic Science and Technology of China, Huzhou 313001, China.
| | - Lu Shao
- MIIT Key Laboratory of Critical Materials Technology for New Energy Conversion and Storage, State Key Laboratory of Urban Water Resource and Environment, School of Chemistry and Chemical Engineering, Harbin Institute of Technology, Harbin 150001, China.
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7
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Zhai X, Lin S, Li X, Wang Z. The Hidden Role of the Dielectric Effect in Nanofiltration: A Novel Perspective to Unravel New Ion Separation Mechanisms. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2024; 58:15874-15884. [PMID: 39173047 DOI: 10.1021/acs.est.4c07510] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/24/2024]
Abstract
Nanofiltration (NF) membranes play a critical role in separation processes, necessitating an in-depth understanding of their selective mechanisms. Existing NF models predominantly include steric and Donnan mechanisms as primary mechanisms. However, these models often fail in elucidating the NF selectivity between ions of similar dimensions and the same valence. To address this gap, an innovative methodology was proposed to unravel new selective mechanisms by quantifying the nominal dielectric effect isolated from steric and Donnan exclusion through fitted pore dielectric constants by regression analysis. We demonstrated that the nominal dielectric effect encompassed unidentified selective mechanisms of significant relevance by establishing the correlation between the fitted pore dielectric constants and these hindrance factors. Our findings revealed that dehydration-induced ion-membrane interaction, rather than ion dehydration, played a pivotal role in ion partitioning within NF membranes. This interaction was closely linked to the nondeformable fraction of hydrated ions. Further delineation of the dielectric effect showed that favorable interactions between ions and membrane functional groups contributed to entropy-driven selectivity, which is a key factor in explaining ion selectivity differences between ions sharing the same size and valence. This study deepens our understanding of NF selectivity and sheds light on the design of highly selective membranes for water and wastewater treatment.
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Affiliation(s)
- Xiaohu Zhai
- State Key Laboratory of Pollution Control and Resource Reuse, Shanghai Institute of Pollution Control and Ecological Security, Tongji Advanced Membrane Technology Center, School of Environmental Science and Engineering, Tongji University, Shanghai 200092, China
| | - Shihong Lin
- Department of Civil and Environmental Engineering, Vanderbilt University, Nashville, Tennessee 37235-1831, United States
| | - Xuesong Li
- State Key Laboratory of Pollution Control and Resource Reuse, Shanghai Institute of Pollution Control and Ecological Security, Tongji Advanced Membrane Technology Center, School of Environmental Science and Engineering, Tongji University, Shanghai 200092, China
| | - Zhiwei Wang
- State Key Laboratory of Pollution Control and Resource Reuse, Shanghai Institute of Pollution Control and Ecological Security, Tongji Advanced Membrane Technology Center, School of Environmental Science and Engineering, Tongji University, Shanghai 200092, China
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Liu K, Epsztein R, Lin S, Qu J, Sun M. Ion-Ion Selectivity of Synthetic Membranes with Confined Nanostructures. ACS NANO 2024; 18:21633-21650. [PMID: 39114876 DOI: 10.1021/acsnano.4c00540] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/21/2024]
Abstract
Synthetic membranes featuring confined nanostructures have emerged as a prominent category of leading materials that can selectively separate target ions from complex water matrices. Further advancements in these membranes will pressingly rely on the ability to elucidate the inherent connection between transmembrane ion permeation behaviors and the ion-selective nanostructures. In this review, we first abstract state-of-the-art nanostructures with a diversity of spatial confinements in current synthetic membranes. Next, the underlying mechanisms that govern ion permeation under the spatial nanoconfinement are analyzed. We then proceed to assess ion-selective membrane materials with a focus on their structural merits that allow ultrahigh selectivity for a wide range of monovalent and divalent ions. We also highlight recent advancements in experimental methodologies for measuring ionic permeability, hydration numbers, and energy barriers to transport. We conclude by putting forth the future research prospects and challenges in the realm of high-performance ion-selective membranes.
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Affiliation(s)
- Kairui Liu
- Center for Water and Ecology, State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China
| | - Razi Epsztein
- Faculty of Civil and Environmental Engineering, Technion-Israel Institute of Technology, Haifa 32000, Israel
| | - Shihong Lin
- Department of Civil and Environmental Engineering and Department of Chemical and Biomolecular Engineering, Vanderbilt University, Nashville, Tennessee 37235-1831, United States
| | - Jiuhui Qu
- Center for Water and Ecology, State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China
- State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Meng Sun
- Center for Water and Ecology, State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China
- State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
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Kumar A, Chang DW. Optimized Polymeric Membranes for Water Treatment: Fabrication, Morphology, and Performance. Polymers (Basel) 2024; 16:271. [PMID: 38257070 PMCID: PMC10819000 DOI: 10.3390/polym16020271] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2023] [Revised: 01/05/2024] [Accepted: 01/09/2024] [Indexed: 01/24/2024] Open
Abstract
Conventional polymers, endowed with specific functionalities, are extensively utilized for filtering and extracting a diverse set of chemicals, notably metals, from solutions. The main structure of a polymer is an integral part for designing an efficient separating system. However, its chemical functionality further contributes to the selectivity, fabrication process, and resulting product morphology. One example would be a membrane that can be employed to selectively remove a targeted metal ion or chemical from a solution, leaving behind the useful components of the solution. Such membranes or products are highly sought after for purifying polluted water contaminated with toxic and heavy metals. An efficient water-purifying membrane must fulfill several requirements, including a specific morphology attained by the material with a specific chemical functionality and facile fabrication for integration into a purifying module Therefore, the selection of an appropriate polymer and its functionalization become crucial and determining steps. This review highlights the attempts made in functionalizing various polymers (including natural ones) or copolymers with chemical groups decisive for membranes to act as water purifiers. Among these recently developed membrane systems, some of the materials incorporating other macromolecules, e.g., MOFs, COFs, and graphene, have displayed their competence for water treatment. Furthermore, it also summarizes the self-assembly and resulting morphology of the membrane materials as critical for driving the purification mechanism. This comprehensive overview aims to provide readers with a concise and conclusive understanding of these materials for water purification, as well as elucidating further perspectives and challenges.
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Affiliation(s)
| | - Dong Wook Chang
- Department of Industrial Chemistry, ECS Core Research Institute, Pukyong National University, Busan 48513, Republic of Korea;
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Kim N, Oh W, Knust KN, Zazyki Galetto F, Su X. Molecularly Selective Polymer Interfaces for Electrochemical Separations. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2023; 39:16685-16700. [PMID: 37955994 DOI: 10.1021/acs.langmuir.3c02389] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2023]
Abstract
The molecular design of polymer interfaces has been key for advancing electrochemical separation processes. Precise control of molecular interactions at electrochemical interfaces has enabled the removal or recovery of charged species with enhanced selectivity, capacity, and stability. In this Perspective, we provide an overview of recent developments in polymer interfaces applied to liquid-phase electrochemical separations, with a focus on their role as electrosorbents as well as membranes in electrodialysis systems. In particular, we delve into both the single-site and macromolecular design of redox polymers and their use in heterogeneous electrochemical separation platforms. We highlight the significance of incorporating both redox-active and non-redox-active moieties to tune binding toward ever more challenging separations, including structurally similar species and even isomers. Furthermore, we discuss recent advances in the development of selective ion-exchange membranes for electrodialysis and the critical need to control the physicochemical properties of the polymer. Finally, we share perspectives on the challenges and opportunities in electrochemical separations, ranging from the need for a comprehensive understanding of binding mechanisms to the continued innovation of electrochemical architectures for polymer electrodes.
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Affiliation(s)
- Nayeong Kim
- Department of Chemical and Biomolecular Engineering, University of Illinois Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Wangsuk Oh
- Department of Chemical and Biomolecular Engineering, University of Illinois Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Kyle N Knust
- Department of Chemistry, Millikin University, 1184 W. Main Street, Decatur, Illinois 62522, United States
| | - Fábio Zazyki Galetto
- Departamento de Química, Universidade Federal de Santa Catarina (UFSC), Florianopolis SC 88040-900, Brazil
| | - Xiao Su
- Department of Chemical and Biomolecular Engineering, University of Illinois Urbana-Champaign, Urbana, Illinois 61801, United States
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11
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Jeong N, Epsztein R, Wang R, Park S, Lin S, Tong T. Exploring the Knowledge Attained by Machine Learning on Ion Transport across Polyamide Membranes Using Explainable Artificial Intelligence. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023; 57:17851-17862. [PMID: 36917705 DOI: 10.1021/acs.est.2c08384] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
Recent studies have increasingly applied machine learning (ML) to aid in performance and material design associated with membrane separation. However, whether the knowledge attained by ML with a limited number of available data is enough to capture and validate the fundamental principles of membrane science remains elusive. Herein, we applied explainable artificial intelligence (XAI) to thoroughly investigate the knowledge learned by ML on the mechanisms of ion transport across polyamide reverse osmosis (RO) and nanofiltration (NF) membranes by leveraging 1,585 data from 26 membrane types. The Shapley additive explanation method based on cooperative game theory was used to unveil the influences of various ion and membrane properties on the model predictions. XAI shows that the ML can capture the important roles of size exclusion and electrostatic interaction in regulating membrane separation properly. XAI also identifies that the mechanisms governing ion transport possess different relative importance to cation and anion rejections during RO and NF filtration. Overall, we provide a framework to evaluate the knowledge underlying the ML model prediction and demonstrate that ML is able to learn fundamental mechanisms of ion transport across polyamide membranes, highlighting the importance of elucidating model interpretability for more reliable and explainable ML applications to membrane selection and design.
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Affiliation(s)
- Nohyeong Jeong
- Department of Civil and Environmental Engineering, Colorado State University, Fort Collins, Colorado 80523, United States
| | - Razi Epsztein
- Department of Civil and Environmental Engineering, Technion - Israel Institute of Technology, Haifa 32000, Israel
| | - Ruoyu Wang
- Department of Civil and Environmental Engineering, Vanderbilt University, Nashville, Tennessee 37235-1831, United States
| | - Shinyun Park
- Department of Civil and Environmental Engineering, Colorado State University, Fort Collins, Colorado 80523, United States
| | - Shihong Lin
- Department of Civil and Environmental Engineering, Vanderbilt University, Nashville, Tennessee 37235-1831, United States
- Department of Chemical and Bimolecular Engineering, Vanderbilt University, Nashville, Tennessee 37235-1831, United States
| | - Tiezheng Tong
- Department of Civil and Environmental Engineering, Colorado State University, Fort Collins, Colorado 80523, United States
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12
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Zhang Z, Chen M, Zhan W, Chen Y, Wang T, Chen Z, Fu Y, Zhao G, Mao D, Ruan J, Yuan FL. Acid-sensing ion channel 1a modulation of apoptosis in acidosis-related diseases: implications for therapeutic intervention. Cell Death Discov 2023; 9:330. [PMID: 37666823 PMCID: PMC10477349 DOI: 10.1038/s41420-023-01624-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2023] [Revised: 07/28/2023] [Accepted: 08/22/2023] [Indexed: 09/06/2023] Open
Abstract
Acid-sensing ion channel 1a (ASIC1a), a prominent member of the acid-sensing ion channel (ASIC) superfamily activated by extracellular protons, is ubiquitously expressed throughout the human body, including the nervous system and peripheral tissues. Excessive accumulation of Ca2+ ions via ASIC1a activation may occur in the acidified microenvironment of blood or local tissues. ASIC1a-mediated Ca2+‑induced apoptosis has been implicated in numerous pathologies, including neurological disorders, cancer, and rheumatoid arthritis. This review summarizes the role of ASIC1a in the modulation of apoptosis via various signaling pathways across different disease states to provide insights for future studies on the underlying mechanisms and development of therapeutic strategies.
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Affiliation(s)
- Zhenyu Zhang
- Institute of Integrated Chinese and Western Medicine, Affiliated to Jiangnan University, Wuxi, Jiangsu, 214041, China
| | - Minnan Chen
- Nantong First People's Hospital, Nantong, 226001, China
| | - Wenjing Zhan
- The Key Laboratory of Anti-Inflammatory and Immune Medicine, Anhui Medical University, Hefei, 230032, China
| | - Yuechun Chen
- Institute of Integrated Chinese and Western Medicine, Affiliated to Jiangnan University, Wuxi, Jiangsu, 214041, China
| | - Tongtong Wang
- Institute of Integrated Chinese and Western Medicine, Affiliated to Jiangnan University, Wuxi, Jiangsu, 214041, China
| | - Zhonghua Chen
- Institute of Integrated Chinese and Western Medicine, Affiliated to Jiangnan University, Wuxi, Jiangsu, 214041, China
| | - Yifei Fu
- Institute of Integrated Chinese and Western Medicine, Affiliated to Jiangnan University, Wuxi, Jiangsu, 214041, China
| | - Gang Zhao
- Orthopaedic Institute, Wuxi 9th People's Hospital Affiliated to Soochow University, Wuxi, 214062, China
| | - Dong Mao
- Orthopaedic Institute, Wuxi 9th People's Hospital Affiliated to Soochow University, Wuxi, 214062, China.
| | - Jingjing Ruan
- Nantong First People's Hospital, Nantong, 226001, China.
- Department of Respiratory and Critical Care Medicine, The First Affiliated Hospital of Anhui Medical University, Hefei, 230022, People's Republic of China.
| | - Feng-Lai Yuan
- Institute of Integrated Chinese and Western Medicine, Affiliated to Jiangnan University, Wuxi, Jiangsu, 214041, China.
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Lu C, Hu C, Chen Z, Wang P, Feng F, He G, Wang F, Zhang Y, Liu JZ, Zhang X, Qu J. Dehydration-enhanced ion-pore interactions dominate anion transport and selectivity in nanochannels. SCIENCE ADVANCES 2023; 9:eadf8412. [PMID: 37418527 PMCID: PMC10328398 DOI: 10.1126/sciadv.adf8412] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2022] [Accepted: 06/06/2023] [Indexed: 07/09/2023]
Abstract
State-of-the-art ion-selective membranes with ultrahigh precision are of significance for water desalination and energy conservation, but their development is limited by the lack of understanding of the mechanisms of ion transport at the subnanometer scale. Herein, we investigate transport of three typical anions (F-, Cl-, and Br-) under confinement using in situ liquid time-of-flight secondary ion mass spectrometry in combination with transition-state theory. The operando analysis reveals that dehydration and related ion-pore interactions govern anion-selective transport. For strongly hydrated ions [(H2O)nF- and (H2O)nCl-], dehydration enhances ion effective charge and thus the electrostatic interactions with membrane, observed as an increase in decomposed energy from electrostatics, leading to more hindered transport. Contrarily, weakly hydrated ions [(H2O)nBr-] have greater permeability as they allow an intact hydration structure during transport due to their smaller size and the most right-skewed hydration distribution. Our work demonstrates that precisely regulating ion dehydration to maximize the difference in ion-pore interactions could enable the development of ideal ion-selective membranes.
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Affiliation(s)
- Chenghai Lu
- State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Chengzhi Hu
- State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Zhibin Chen
- State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Peiyao Wang
- Department of Mechanical Engineering, The University of Melbourne, Parkville, VIC 3010, Australia
| | - Fan Feng
- Department of Mechanical Engineering, The University of Melbourne, Parkville, VIC 3010, Australia
| | - Guangzhi He
- State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Fuyi Wang
- University of Chinese Academy of Sciences, Beijing 100049, China
- Beijing National Laboratory for Molecular Sciences, CAS Key Laboratory of Analytical Chemistry for Living Biosystems, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
| | - Yanyan Zhang
- University of Chinese Academy of Sciences, Beijing 100049, China
- Beijing National Laboratory for Molecular Sciences, CAS Key Laboratory of Analytical Chemistry for Living Biosystems, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
| | - Jefferson Zhe Liu
- Department of Mechanical Engineering, The University of Melbourne, Parkville, VIC 3010, Australia
| | - Xiwang Zhang
- UQ Dow Centre for Sustainable Engineering Innovation, School of Chemical Engineering, The University of Queensland, St. Lucia, QLD 4072, Australia
| | - Jiuhui Qu
- State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
- University of Chinese Academy of Sciences, Beijing 100049, China
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14
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Allouzi M, Imbrogno A, Schäfer AI. Energy Barriers for Steroid Hormone Transport in Nanofiltration. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022; 56:16811-16821. [PMID: 36367435 DOI: 10.1021/acs.est.2c04658] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Nanofiltration (NF) membranes can retain micropollutants (MPs) to a large extent, even though adsorption into the membrane and gradual permeation result in breakthrough and incomplete removal. The permeation of MPs is investigated by examining the energy barriers (determined using the Arrhenius concept) for adsorption, intrapore diffusion, and permeation encountered by four different steroid hormones in tight and loose NF membranes. Results show that the energy barriers for steroid hormone transport in tight membrane are entropically dominated and underestimated because of the high steric exclusion at the pore entrance. In contrast, the loose NF membrane enables steroid hormones partitioning at the pore entrance, with a permeation energy barrier (from feed toward the permeate side) ranging between 96 and 116 kJ/mol. The contribution of adsorption and intrapore diffusion to the energy barrier for steroid hormone permeation reveals a significant role of intrapore diffusive transport on the obtained permeation energy barrier. Overall, the breakthrough phenomenon observed during the NF of MPs is facilitated by the low energy barrier for adsorption. Experimental evidence of such principles is relevant for understanding mechanisms and ultimately improving the selectivity of NF.
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Affiliation(s)
- Mohammad Allouzi
- Institute for Advanced Membrane Technology (IAMT), Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76344Eggenstein-Leopoldshafen, Germany
| | - Alessandra Imbrogno
- Institute for Advanced Membrane Technology (IAMT), Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76344Eggenstein-Leopoldshafen, Germany
| | - Andrea I Schäfer
- Institute for Advanced Membrane Technology (IAMT), Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76344Eggenstein-Leopoldshafen, Germany
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15
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Covalent organic framework membranes for efficient separation of monovalent cations. Nat Commun 2022; 13:7123. [DOI: 10.1038/s41467-022-34849-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2022] [Accepted: 11/09/2022] [Indexed: 11/21/2022] Open
Abstract
AbstractCovalent organic frameworks (COF), with rigid, highly ordered and tunable structures, can actively manipulate the synergy of entropic selectivity and enthalpic selectivity, holding great potential as next-generation membrane materials for ion separations. Here, we demonstrated the efficient separation of monovalent cations by COF membrane. The channels of COF membrane are decorated with three different kinds of acid groups. A concept of confined cascade separation was proposed to elucidate the separation process. The channels of COF membrane comprised two kinds of domains, acid-domains and acid-free-domains. The acid-domains serve as confined stages, rendering high selectivity, while the acid-free-domains preserve the pristine channel size, rendering high permeation flux. A set of descriptors of stage properties were designed to elucidate their effect on selective ion transport behavior. The resulting COF membrane acquired high ion separation performances, with an actual selectivity of 4.2–4.7 for K+/Li+ binary mixtures and an ideal selectivity of ~13.7 for K+/Li+.
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16
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Zhai X, Wang YL, Dai R, Li X, Wang Z. Roles of Anion-Cation Coupling Transport and Dehydration-Induced Ion-Membrane Interaction in Precise Separation of Ions by Nanofiltration Membranes. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022; 56:14069-14079. [PMID: 36126287 DOI: 10.1021/acs.est.2c04772] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Nanofiltration (NF) membranes are playing increasingly crucial roles in addressing emerging environmental challenges by precise separation, yet understanding of the selective transport mechanism is still limited. In this work, the underlying mechanisms governing precise selectivity of the polyamide NF membrane were elucidated using a series of monovalent cations with minor hydrated radius difference. The observed selectivity of a single cation was neither correlated with the hydrated radius nor hydration energy, which could not be explained by the widely accepted NF model or ion dehydration theory. Herein, we employed an Arrhenius approach combined with Monte Carlo simulation to unravel that the transmembrane process of the cation would be dominated by its pairing anion, if the anion has a greater transmembrane energy barrier, due to the constraint of anion-cation coupling transport. Molecular dynamics simulations further revealed that the distinct hydration structure was the primary origin of the energy barrier difference of cations. The cation having a larger incompressible structure after partial dehydration through subnanopores would induce a more significant ion-membrane interaction and consequently a higher energy barrier. Moreover, to validate our proposed mechanisms, a membrane grafting modification toward enlarging the energy barrier difference of dominant ions achieved a 3-fold enhancement in ion separation efficiency. Our work provides insights into the precise separation of ionic species by NF membranes.
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Affiliation(s)
- Xiaohu Zhai
- State Key Laboratory of Pollution Control and Resource Reuse, Shanghai Institute of Pollution Control and Ecological Security, Tongji Advanced Membrane Technology Center, School of Environmental Science and Engineering, Tongji University, Shanghai 200092, China
| | - Yong-Lei Wang
- Department of Materials and Environmental Chemistry, Arrhenius Laboratory, Stockholm University, Stockholm SE-106 91, Sweden
| | - Ruobin Dai
- State Key Laboratory of Pollution Control and Resource Reuse, Shanghai Institute of Pollution Control and Ecological Security, Tongji Advanced Membrane Technology Center, School of Environmental Science and Engineering, Tongji University, Shanghai 200092, China
| | - Xuesong Li
- State Key Laboratory of Pollution Control and Resource Reuse, Shanghai Institute of Pollution Control and Ecological Security, Tongji Advanced Membrane Technology Center, School of Environmental Science and Engineering, Tongji University, Shanghai 200092, China
| | - Zhiwei Wang
- State Key Laboratory of Pollution Control and Resource Reuse, Shanghai Institute of Pollution Control and Ecological Security, Tongji Advanced Membrane Technology Center, School of Environmental Science and Engineering, Tongji University, Shanghai 200092, China
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17
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Shefer I, Lopez K, Straub AP, Epsztein R. Applying Transition-State Theory to Explore Transport and Selectivity in Salt-Rejecting Membranes: A Critical Review. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022; 56:7467-7483. [PMID: 35549171 DOI: 10.1021/acs.est.2c00912] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Membrane technologies using reverse osmosis (RO) and nanofiltration (NF) have been widely implemented in water purification and desalination processes. Separation between species at the molecular level is achievable in RO and NF membranes due to a complex and poorly understood combination of transport mechanisms that have attracted the attention of researchers within and beyond the membrane community for many years. Minimizing existing knowledge gaps in transport through these membranes can improve the sustainability of current water-treatment processes and expand the use of RO and NF membranes to other applications that require high selectivity between species. Since its establishment in 1949, and with growing popularity in recent years, Eyring's transition-state theory (TST) for transmembrane permeation has been applied in numerous studies to mechanistically explore molecular transport in membranes including RO and NF. In this review, we critically assess TST applied to transmembrane permeation in salt-rejecting membranes, focusing on mechanistic insights into transport under confinement that can be gained from this framework and the key limitations associated with the method. We first demonstrate and discuss the limited ability of the commonly used solution-diffusion model to mechanistically explain transport and selectivity trends observed in RO and NF membranes. Next, we review important milestones in the development of TST, introduce its underlying principles and equations, and establish the connection to transmembrane permeation with a focus on molecular-level enthalpic and entropic barriers that govern water and solute transport under confinement. We then critically review the application of TST to explore transport in RO and NF membranes, analyzing trends in measured enthalpic and entropic barriers and synthesizing new data to highlight important phenomena associated with the temperature-dependent measurement of the activation parameters. We also discuss major limitations of the experimental application of TST and propose specific solutions to minimize the uncertainties surrounding the current approach. We conclude with identifying future research needs to enhance the implementation and maximize the benefit of TST application to transmembrane permeation.
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Affiliation(s)
- Idit Shefer
- Faculty of Civil and Environmental Engineering, Technion - Israel Institute of Technology, Haifa 32000, Israel
| | - Kian Lopez
- Department of Civil, Environmental and Architectural Engineering, University of Colorado Boulder, Boulder, Colorado 80309-0428, United States
| | - Anthony P Straub
- Department of Civil, Environmental and Architectural Engineering, University of Colorado Boulder, Boulder, Colorado 80309-0428, United States
| | - Razi Epsztein
- Faculty of Civil and Environmental Engineering, Technion - Israel Institute of Technology, Haifa 32000, Israel
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18
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Yong H, He X, Merlitz H. Connection between Intrapore Free Energy, Molecule Permeation, and Selectivity of Nanofiltration Membranes. Macromolecules 2022. [DOI: 10.1021/acs.macromol.2c00317] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Huaisong Yong
- Department of Polymer Materials and Engineering, School of New Energy and Materials, Southwest Petroleum University, 610500, Chengdu, China
- Institute Theory of Polymers, Leibniz-Institut für Polymerforschung Dresden e.V., D-01069, Dresden, Germany
| | - Xianru He
- Department of Polymer Materials and Engineering, School of New Energy and Materials, Southwest Petroleum University, 610500, Chengdu, China
| | - Holger Merlitz
- Institute Theory of Polymers, Leibniz-Institut für Polymerforschung Dresden e.V., D-01069, Dresden, Germany
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20
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Pavluchkov V, Shefer I, Peer-Haim O, Blotevogel J, Epsztein R. Indications of ion dehydration in diffusion-only and pressure-driven nanofiltration. J Memb Sci 2022. [DOI: 10.1016/j.memsci.2022.120358] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
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