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Ponomar M, Ruleva V, Sarapulova V, Pismenskaya N, Nikonenko V, Maryasevskaya A, Anokhin D, Ivanov D, Sharma J, Kulshrestha V, Améduri B. Structural Characterization and Physicochemical Properties of Functionally Porous Proton-Exchange Membrane Based on PVDF-SPA Graft Copolymers. Int J Mol Sci 2024; 25:598. [PMID: 38203772 PMCID: PMC10779367 DOI: 10.3390/ijms25010598] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2023] [Revised: 12/08/2023] [Accepted: 12/29/2023] [Indexed: 01/12/2024] Open
Abstract
Fluorinated proton-exchange membranes (PEMs) based on graft copolymers of dehydrofluorinated polyvinylidene fluoride (D-PVDF), 3-sulfopropyl acrylate (SPA), and 1H, 1H, 2H-perfluoro-1-hexene (PFH) were prepared via free radical copolymerization and characterized for fuel cell application. The membrane morphology and physical properties were studied via small-(SAXS) and wide-angle X-ray scattering (WAXS), SEM, and DSC. It was found that the crystallinity degree is 17% for PEM-RCF (co-polymer with SPA) and 16% for PEM-RCF-2 (copolymer with SPA and PFH). The designed membranes possess crystallite grains of 5-6 nm in diameter. SEM images reveal a structure with open pores on the surface of diameters from 20 to 140 nm. Their transport and electrochemical characterization shows that the lowest membrane area resistance (0.9 Ωcm2) is comparable to perfluorosulfonic acid PEMs (such as Nafion®) and polyvinylidene fluoride (PVDF) based CJMC cation-exchange membranes (ChemJoy Polymer Materials, China). Key transport and physicochemical properties of new and commercial membranes were compared. The PEM-RCF permeability to NaCl diffusion is rather high, which is due to a relatively low concentration of fixed sulfonate groups. Voltammetry confers that the electrochemical behavior of new PEM correlates to that of commercial cation-exchange membranes, while the ionic conductivity reveals an impact of the extended pores, as in track-etched membranes.
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Affiliation(s)
- Maria Ponomar
- Department of Physical Chemistry, Kuban State University, 350040 Krasnodar, Russia
| | - Valentina Ruleva
- Department of Physical Chemistry, Kuban State University, 350040 Krasnodar, Russia
| | - Veronika Sarapulova
- Department of Physical Chemistry, Kuban State University, 350040 Krasnodar, Russia
| | - Natalia Pismenskaya
- Department of Physical Chemistry, Kuban State University, 350040 Krasnodar, Russia
| | - Victor Nikonenko
- Department of Physical Chemistry, Kuban State University, 350040 Krasnodar, Russia
- Faculty of Fundamental Physical and Chemical Engineering, Lomonosov Moscow State University, 119991 Moscow, Russia (B.A.)
| | - Alina Maryasevskaya
- Faculty of Fundamental Physical and Chemical Engineering, Lomonosov Moscow State University, 119991 Moscow, Russia (B.A.)
- Federal Research Center of Problems of Chemical Physics and Medicinal Chemistry Russian Academy of Sciences, 142432 Chernogolovka, Russia
| | - Denis Anokhin
- Faculty of Fundamental Physical and Chemical Engineering, Lomonosov Moscow State University, 119991 Moscow, Russia (B.A.)
- Federal Research Center of Problems of Chemical Physics and Medicinal Chemistry Russian Academy of Sciences, 142432 Chernogolovka, Russia
- Center for Genetics and Life Science, Sirius University of Science and Technology, 354340 Sochi, Russia
| | - Dimitri Ivanov
- Faculty of Fundamental Physical and Chemical Engineering, Lomonosov Moscow State University, 119991 Moscow, Russia (B.A.)
- Federal Research Center of Problems of Chemical Physics and Medicinal Chemistry Russian Academy of Sciences, 142432 Chernogolovka, Russia
- Center for Genetics and Life Science, Sirius University of Science and Technology, 354340 Sochi, Russia
- Institut de Sciences des Matériaux de Mulhouse-IS2M, CNRS UMR 7361, 68057 Mulhouse, France
| | - Jeet Sharma
- Institute Charles Gerhardt, CNRS, University of Montpellier, Ecole Nationale Supérieure de Chimie de Montpellier, 34000 Montpellier, France;
- Membrane Science and Separation Technology Division, Council of Scientific and Industrial Research, Central Salt and Marine Chemicals Research Institute (CSIR-CSMCRI), Bhavnagar 364002, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
| | - Vaibhav Kulshrestha
- Membrane Science and Separation Technology Division, Council of Scientific and Industrial Research, Central Salt and Marine Chemicals Research Institute (CSIR-CSMCRI), Bhavnagar 364002, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
| | - Bruno Améduri
- Faculty of Fundamental Physical and Chemical Engineering, Lomonosov Moscow State University, 119991 Moscow, Russia (B.A.)
- Institute Charles Gerhardt, CNRS, University of Montpellier, Ecole Nationale Supérieure de Chimie de Montpellier, 34000 Montpellier, France;
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Wu L, Jiang H, Luo T, Wang X. On the Ionic Conductivity of Cation Exchange Membranes in Mixed Sulfates Using the Two-Phase Model. MEMBRANES 2023; 13:811. [PMID: 37887983 PMCID: PMC10608779 DOI: 10.3390/membranes13100811] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2023] [Revised: 09/15/2023] [Accepted: 09/19/2023] [Indexed: 10/28/2023]
Abstract
The concentration dependence of the conductivity of ion exchange membranes (IEMs), as well as other transport properties, has been well explained by the contemporary two-phase model (Zabolotsky et al., 1993) considering a gel phase and an inter-gel phase filled with electroneutral solution. Here, this two-phase model has been adopted and first applied in electrolytes containing mixed counter-ions to investigate the correlation between the membrane ionic conductivity and its microstructure. For three representative commercial cation exchange membranes (CEMs), the total membrane conductivity (κT) when in equilibrium with mixed MgSO4 + Na2SO4 and H2SO4 + Na2SO4 electrolytes could be well predicted with the experimental composition of counter-ions in the gel and inter-gel phase, as well as the counter-ion mobility in the gel phase when the membrane is in a single electrolyte. It is found that the volume fraction of the inter-gel phase (f2) has little impact on the predicted results. The accuracy of the model can be largely improved by calculating the inter-gel phase conductivity (κin) with the ionic mobility being the same as that in the external solution (obtained via simulation in the OLI Studio), rather than simply as equivalent to the conductivity of the external solution (κs). Moreover, a nonlinear correlation between the CEMs' conductivities and the counter-ion composition in the gel phase is observed in the mixed MgSO4 + Na2SO4 solution, as well as for the Nafion117 membrane in the presence of sulfuric acid. For CEMs in mixed MgSO4 + Na2SO4 electrolytes, the calculated conductivity values considering the interaction parameter σ, similar to the Kohlrausch's law, are closer to the experimental ones. Overall, this work provides new insights into membrane conductivity with mixed counter-ions and testifies to the applicability of the contemporary two-phase model.
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Affiliation(s)
| | | | - Tao Luo
- Ministry of Education’s Research Center for Comprehensive Utilization and Clean Process Engineering of Phosphorous Resources, School of Chemical Engineering, Sichuan University, Chengdu 610065, China
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Pismenskaya N, Rybalkina O, Solonchenko K, Butylskii D, Nikonenko V. Phosphates Transfer in Pristine and Modified CJMA-2 Membrane during Electrodialysis Processing of Na xH (3-x)PO 4 Solutions with pH from 4.5 to 9.9. MEMBRANES 2023; 13:647. [PMID: 37505013 PMCID: PMC10386648 DOI: 10.3390/membranes13070647] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/23/2023] [Revised: 06/27/2023] [Accepted: 07/03/2023] [Indexed: 07/29/2023]
Abstract
Phosphate recovery from different second streams using electrodialysis (ED) is a promising step to a nutrients circular economy. However, the relatively low ED performance hinders the widespread adoption of this environmentally sound method. The formation of "bonded species" between phosphates and the weakly basic fixed groups (primary and secondary amines) of the anion exchange membrane can be the cause of decrease in current efficiency and increase in energy consumption. ED processing of NaxH(3-x)PO4 alkaline solutions and the use of intense current modes promote the formation of a bipolar junction from negatively charged bound species and positively charged fixed groups. This phenomenon causes a change in the shape of current-voltage curves, increase in resistance, and an enhancement in proton generation during long-term operation of anion-exchange membrane with weakly basic fixed groups. Shielding of primary and secondary amines with a modifier containing quaternary ammonium bases significantly improves ED performance in the recovery of phosphates from NaxH(3-x)PO4 solution with pH 4.5. Indeed, in the limiting and underlimiting current modes, 40% of phosphates are recovered 1.3 times faster, and energy consumption is reduced by 1.9 times in the case of the modified membrane compared to the pristine one. Studies were performed using a new commercial anion exchange membrane CJMA-2.
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Affiliation(s)
- Natalia Pismenskaya
- Russian Federation, Kuban State University, 149, Stavropolskaya Str., 350040 Krasnodar, Russia
| | - Olesya Rybalkina
- Russian Federation, Kuban State University, 149, Stavropolskaya Str., 350040 Krasnodar, Russia
| | - Ksenia Solonchenko
- Russian Federation, Kuban State University, 149, Stavropolskaya Str., 350040 Krasnodar, Russia
| | - Dmitrii Butylskii
- Russian Federation, Kuban State University, 149, Stavropolskaya Str., 350040 Krasnodar, Russia
| | - Victor Nikonenko
- Russian Federation, Kuban State University, 149, Stavropolskaya Str., 350040 Krasnodar, Russia
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Pismenskaya N, Rybalkina O, Solonchenko K, Pasechnaya E, Sarapulova V, Wang Y, Jiang C, Xu T, Nikonenko V. How Chemical Nature of Fixed Groups of Anion-Exchange Membranes Affects the Performance of Electrodialysis of Phosphate-Containing Solutions? Polymers (Basel) 2023; 15:polym15102288. [PMID: 37242863 DOI: 10.3390/polym15102288] [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: 03/27/2023] [Revised: 05/03/2023] [Accepted: 05/09/2023] [Indexed: 05/28/2023] Open
Abstract
Innovative ion exchange membranes have become commercially available in recent years. However, information about their structural and transport characteristics is often extremely insufficient. To address this issue, homogeneous anion exchange membranes with the trade names ASE, CJMA-3 and CJMA-6 have been investigated in NaxH(3-x)PO4 solutions with pH 4.4 ± 0.1, 6.6 and 10.0 ± 0.2, as well as NaCl solutions with pH 5.5 ± 0.1. Using IR spectroscopy and processing the concentration dependences of the electrical conductivity of these membranes in NaCl solutions, it was shown that ASE has a highly cross-linked aromatic matrix and mainly contains quaternary ammonium groups. Other membranes have a less cross-linked aliphatic matrix based on polyvinylidene fluoride (CJMA-3) or polyolefin (CJMA-6) and contain quaternary amines (CJMA-3) or a mixture of strongly basic (quaternary) and weakly basic (secondary) amines (CJMA-6). As expected, in dilute solutions of NaCl, the conductivity of membranes increases with an increase in their ion-exchange capacity: CJMA-6 < CJMA-3 << ASE. Weakly basic amines appear to form bound species with proton-containing phosphoric acid anions. This phenomenon causes a decrease in the electrical conductivity of CJMA-6 membranes compared to other studied membranes in phosphate-containing solutions. In addition, the formation of the neutral and negatively charged bound species suppresses the generation of protons by the "acid dissociation" mechanism. Moreover, when the membrane is operated in overlimiting current modes and/or in alkaline solutions, a bipolar junction is formed at the CJMA- 6/depleted solution interface. The CJMA-6 current-voltage curve becomes similar to the well-known curves for bipolar membranes, and water splitting intensifies in underlimiting and overlimiting modes. As a result, energy consumption for electrodialysis recovery of phosphates from aqueous solutions almost doubles when using the CJMA-6 membrane compared to the CJMA-3 membrane.
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Affiliation(s)
- Natalia Pismenskaya
- Russian Federation, Kuban State University, 149, Stavropolskaya Str., 350040 Krasnodar, Russia
| | - Olesya Rybalkina
- Russian Federation, Kuban State University, 149, Stavropolskaya Str., 350040 Krasnodar, Russia
| | - Ksenia Solonchenko
- Russian Federation, Kuban State University, 149, Stavropolskaya Str., 350040 Krasnodar, Russia
| | - Evgeniia Pasechnaya
- Russian Federation, Kuban State University, 149, Stavropolskaya Str., 350040 Krasnodar, Russia
| | - Veronika Sarapulova
- Russian Federation, Kuban State University, 149, Stavropolskaya Str., 350040 Krasnodar, Russia
| | - Yaoming Wang
- Anhui Provincial Engineering Laboratory of Functional Membrane Science and Technology, Department of Applied Chemistry, School of Chemistry and Materials Science, University of Science and Technology of China, Hefei 230026, China
| | - Chenxiao Jiang
- Anhui Provincial Engineering Laboratory of Functional Membrane Science and Technology, Department of Applied Chemistry, School of Chemistry and Materials Science, University of Science and Technology of China, Hefei 230026, China
| | - Tongwen Xu
- Anhui Provincial Engineering Laboratory of Functional Membrane Science and Technology, Department of Applied Chemistry, School of Chemistry and Materials Science, University of Science and Technology of China, Hefei 230026, China
| | - Victor Nikonenko
- Russian Federation, Kuban State University, 149, Stavropolskaya Str., 350040 Krasnodar, Russia
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Veerman J, Gómez-Coma L, Ortiz A, Ortiz I. Resistance of Ion Exchange Membranes in Aqueous Mixtures of Monovalent and Divalent Ions and the Effect on Reverse Electrodialysis. MEMBRANES 2023; 13:322. [PMID: 36984709 PMCID: PMC10056131 DOI: 10.3390/membranes13030322] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/16/2023] [Revised: 03/01/2023] [Accepted: 03/06/2023] [Indexed: 06/18/2023]
Abstract
Salinity gradient energy has gained attention in recent years as a renewable energy source, especially employing reverse electrodialysis technology (RED), which is based on the role of ion exchange membranes. In this context, many efforts have been developed by researchers from all over the world to advance the knowledge of this green source of energy. However, the influence of divalent ions on the performance of the technology has not been deeply studied. Basically, divalent ions are responsible for an increased membrane resistance and, therefore, for a decrease in voltage. This work focuses on the estimation of the resistance of the RED membrane working with water flows containing divalent ions, both theoretically by combining the one-thread model with the Donnan exclusion theory for the gel phase, as well as the experimental evaluation with Fumatech membranes FAS-50, FKS-50, FAS-PET-75, and FKS-PET-75. Furthermore, simulated results have been compared to data recently reported with different membranes. Besides, the influence of membrane resistance on the overall performance of reverse electrodialysis technology is evaluated to understand the impact of divalent ions in energy generation. Results reflect a minor effect of sulfate on the gross power in comparison to the effect of calcium and magnesium ions. Thus, this work takes a step forward in the knowledge of reverse electrodialysis technology and the extraction of salinity gradient energy by advancing the influence of divalent ions on energy recovery.
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Affiliation(s)
- Joost Veerman
- REDstack BV, Graaf Adolfstraat 35-G, 8606 BT Sneek, The Netherlands
| | - Lucía Gómez-Coma
- Departmento de Ingenierías Químicas y Biomolecular, Universidad de Cantabria, Av. Los Castros 46, 39005 Santander, Spain
| | - Alfredo Ortiz
- Departmento de Ingenierías Químicas y Biomolecular, Universidad de Cantabria, Av. Los Castros 46, 39005 Santander, Spain
| | - Inmaculada Ortiz
- Departmento de Ingenierías Químicas y Biomolecular, Universidad de Cantabria, Av. Los Castros 46, 39005 Santander, Spain
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Kozmai A, Porozhnyy M, Ruleva V, Gorobchenko A, Pismenskaya N, Nikonenko V. Is It Possible to Prepare a "Super" Anion-Exchange Membrane by a Polypyrrole-Based Modification? MEMBRANES 2023; 13:103. [PMID: 36676909 PMCID: PMC9865286 DOI: 10.3390/membranes13010103] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/25/2022] [Revised: 01/05/2023] [Accepted: 01/10/2023] [Indexed: 06/17/2023]
Abstract
In spite of wide variety of commercial ion-exchange membranes, their characteristics, in particular, electrical conductivity and counterion permselectivity, are unsatisfactory for some applications, such as electrolyte solution concentration. This study is aimed at obtaining an anion-exchange membrane (AEM) of high performance in concentrated solutions. An AEM is prepared with a polypyrrole (PPy)-based modification of a heterogeneous AEM with quaternary ammonium functional groups. Concentration dependences of the conductivity, diffusion permeability and Cl− transport number in NaCl solutions are measured and simulated using a new version of the microheterogeneous model. The model describes changes in membrane swelling with increasing concentration and the effect of these changes on the transport characteristics. It is assumed that PPy occupies macro- and mesopores of the host membrane where it replaces non-selective electroneutral solution. Increasing conductivity and selectivity are explained by the presence of positively charged PPy groups. It is found that the conductivity of a freshly prepared membrane reaches 20 mS/cm and the chloride transport number > 0.99 in 4 M NaCl. A choice of input parameters allows quantitative agreement between the experimental and simulation results. However, PPy has shown itself to be an unstable material. This article discusses what parameters a membrane can have to show such exceptional characteristics.
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Pasechnaya E, Tsygurina K, Ponomar M, Chuprynina D, Nikonenko V, Pismenskaya N. Comparison of the Electrodialysis Performance in Tartrate Stabilization of a Red Wine Using Aliphatic and Aromatic Commercial and Modified Ion-Exchange Membranes. MEMBRANES 2023; 13:membranes13010084. [PMID: 36676891 PMCID: PMC9862077 DOI: 10.3390/membranes13010084] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Revised: 12/31/2022] [Accepted: 01/05/2023] [Indexed: 06/01/2023]
Abstract
The application of electrodialysis for tartrate stabilization and reagent-free acidity correction of wine and juices is attracting increasing interest. New aliphatic membranes CJMC-3 and CJMA-3 and aromatic membranes CSE and ASE were tested to determine their suitability for use in these electrodialysis processes and to evaluate the fouling of these membranes by wine components for a short (6-8 h) operating time. Using IR spectroscopy, optical indication and measurement of surface contact angles, the chemical composition of the studied membranes, as well as some details about their fouling by wine components, was clarified. The current-voltage charsacteristics, conductivity and water-splitting capacity of the membranes before and after electrodialysis were analyzed. We found that in the case of cation-exchange membranes, complexes of anthocyanins with metal ions penetrate into the bulk (CJMC-3) or are localized on the surface (CSE), depending on the degree of crosslinking of the polymer matrix. Adsorption of wine components by the surface of anion-exchange membranes CJMA-3 and ASE causes an increase in water splitting. Despite fouling under identical conditions of electrodialysis, membrane pair CJMC-3 and CJMA-3 provided 18 ± 1 tartrate recovery with 31 · 10-3 energy consumption, whereas CSE and ASE provided 20 ± 1% tartrate recovery with an energy consumption of 28 · 10-3 Wh, in addition to reducing the conductivity of wine by 20 ± 1%. The casting of aliphatic polyelectrolyte films on the surface of aromatic membranes reduces fouling with a relatively small increase in energy consumption and approximately the same degree of tartrate recovery compared to pristine CSE and ASE.
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Affiliation(s)
| | - Kseniia Tsygurina
- Membrane Institute, Kuban State University, 350040 Krasnodar, Russia
| | - Maria Ponomar
- Membrane Institute, Kuban State University, 350040 Krasnodar, Russia
| | - Daria Chuprynina
- Department of Analytical Chemistry, Kuban State University, 350040 Krasnodar, Russia
| | - Victor Nikonenko
- Membrane Institute, Kuban State University, 350040 Krasnodar, Russia
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Tsygurina K, Pasechnaya E, Chuprynina D, Melkonyan K, Rusinova T, Nikonenko V, Pismenskaya N. Electrodialysis Tartrate Stabilization of Wine Materials: Fouling and a New Approach to the Cleaning of Aliphatic Anion-Exchange Membranes. MEMBRANES 2022; 12:1187. [PMID: 36557094 PMCID: PMC9785266 DOI: 10.3390/membranes12121187] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/07/2022] [Revised: 11/22/2022] [Accepted: 11/23/2022] [Indexed: 06/17/2023]
Abstract
Electrodialysis (ED) is an attractive method of tartrate stabilization of wine due to its rapidity and reagentlessness. At the same time, fouling of ion-exchange membranes by the components of wine materials is still an unsolved problem. The effect of ethanol, polyphenols (mainly anthocyanins and proanthocyanidins) and saccharides (fructose) on the fouling of aliphatic ion-exchange membranes CJMA-6 and CJMC-5 (manufactured by Hefei Chemjoy Polymer Materials Co. Ltd., Hefei, China) was analyzed using model solutions. It was shown that the mechanism and consequences of fouling are different in the absence of an electric field and during electrodialysis. In particular, a layer of colloidal particles is deposited on the surface of the CJMA-6 anion-exchange membrane in underlimiting current modes. Its thickness increases with increasing current density, apparently due to the implementation of a trap mechanism involving tartaric acid anions, as well as protons, which are products of water splitting and "acid dissociation". A successful attempt was made to clean CJMA-6 in operando by pumping a water-alcohol solution of KCl through the desalination compartment and changing electric field direction. It has been established that such a cleaning process suppresses the subsequent biofouling of ion-exchange membranes. In addition, selective recovery of polyphenols with high antioxidant activity is possible.
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Affiliation(s)
- Kseniia Tsygurina
- Membrane Institute, Kuban State University, 350040 Krasnodar, Russia
| | | | - Daria Chuprynina
- Department of Analytical Chemistry, Kuban State University, 350040 Krasnodar, Russia
| | - Karina Melkonyan
- Central Research Laboratory, Kuban State Medical University, 350040 Krasnodar, Russia
| | - Tatyana Rusinova
- Central Research Laboratory, Kuban State Medical University, 350040 Krasnodar, Russia
| | - Victor Nikonenko
- Membrane Institute, Kuban State University, 350040 Krasnodar, Russia
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Sessile Drop Method: Critical Analysis and Optimization for Measuring the Contact Angle of an Ion-Exchange Membrane Surface. MEMBRANES 2022; 12:membranes12080765. [PMID: 36005679 PMCID: PMC9412394 DOI: 10.3390/membranes12080765] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/19/2022] [Revised: 07/31/2022] [Accepted: 08/01/2022] [Indexed: 11/17/2022]
Abstract
The contact angle between a membrane surface and a waterdrop lying on its surface provides important information about the hydrophilicity/hydrophobicity of the membrane. This method is well-developed for solid non-swelling materials. However, ion-exchange membranes (IEMs) are gel-like solids that swell in liquids. When an IEM is exposed to air, its degree of swelling changes rapidly, making it difficult to measure the contact angle. In this paper, we examine the known experience of measuring contact angles and suggest a simple equipment that allows the membrane to remain swollen during measurements. An optimized protocol makes it possible to obtain reliable and reproducible results. Measuring parameters such as drop size, water dosing speed and others are optimized. Contact angle measurements are shown for a large number of commercial membranes. These data are supplemented with values from other surface characteristics from optical and profilometric measurements.
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Kozmai A, Pismenskaya N, Nikonenko V. Mathematical Description of the Increase in Selectivity of an Anion-Exchange Membrane Due to Its Modification with a Perfluorosulfonated Ionomer. Int J Mol Sci 2022; 23:ijms23042238. [PMID: 35216352 PMCID: PMC8877549 DOI: 10.3390/ijms23042238] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2021] [Revised: 02/11/2022] [Accepted: 02/14/2022] [Indexed: 02/04/2023] Open
Abstract
In this paper, we simulate the changes in the structure and transport properties of an anion-exchange membrane (CJMA-7, Hefei Chemjoy Polymer Materials Co. Ltd., China) caused by its modification with a perfluorosulfonated ionomer (PFSI). The modification was made in several stages and included keeping the membrane at a low temperature, applying a PFSI solution on its surface, and, subsequently, drying it at an elevated temperature. We applied the known microheterogeneous model with some new amendments to simulate each stage of the membrane modification. It has been shown that the PFSI film formed on the membrane-substrate does not affect significantly its properties due to the small thickness of the film (≈4 µm) and similar properties of the film and substrate. The main effect is caused by the fact that PFSI material “clogs” the macropores of the CJMA-7 membrane, thereby, blocking the transport of coions through the membrane. In this case, the membrane microporous gel phase, which exhibits a high selectivity to counterions, remains the primary pathway for both counterions and coions. Due to the above modification of the CJMA-7 membrane, the coion (Na+) transport number in the membrane equilibrated with 1 M NaCl solution decreased from 0.11 to 0.03. Thus, the modified membrane became comparable in its transport characteristics with more expensive IEMs available on the market.
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Mikhailov OV. The Physical Chemistry and Chemical Physics (PCCP) Section of the International Journal of Molecular Sciences in Its Publications: The First 300 Thematic Articles in the First 3 Years. Int J Mol Sci 2021; 23:241. [PMID: 35008667 PMCID: PMC8745423 DOI: 10.3390/ijms23010241] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2021] [Accepted: 12/15/2021] [Indexed: 11/16/2022] Open
Abstract
The Physical Chemistry and Chemical Physics Section (PCCP Section) is one of the youngest among the sections of the International Journal of Molecular Sciences (IJMS)-the year 2021 will only mark three years since its inception [...].
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Affiliation(s)
- Oleg V Mikhailov
- Department of Analytical Chemistry, Certification and Quality Management, Kazan National Research Technological University, K. Marx Street 68, 420015 Kazan, Russia
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12
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Golubenko D, Yaroslavtsev A. Effect of current density, concentration of ternary electrolyte and type of cations on the monovalent ion selectivity of surface-sulfonated graft anion-exchange membranes: modelling and experiment. J Memb Sci 2021. [DOI: 10.1016/j.memsci.2021.119466] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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13
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Use of the Microheterogeneous Model to Assess the Applicability of Ion-Exchange Membranes in the Process of Generating Electricity from a Concentration Gradient. MEMBRANES 2021; 11:membranes11060406. [PMID: 34071631 PMCID: PMC8230344 DOI: 10.3390/membranes11060406] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/22/2021] [Revised: 05/20/2021] [Accepted: 05/21/2021] [Indexed: 11/18/2022]
Abstract
The paper shows the possibility of using a microheterogeneous model to estimate the transport numbers of counterions through ion-exchange membranes. It is possible to calculate the open-circuit potential and power density of the reverse electrodialyzer using the data obtained. Eight samples of heterogeneous ion-exchange membranes were studied, two samples for each of the following types of membranes: Ralex CM, Ralex AMH, MK-40, and MA-41. Samples in each pair differed in the year of production and storage conditions. In the work, these samples were named “batch 1” and “batch 2”. According to the microheterogeneous model, to calculate the transport numbers of counterions, it is necessary to use the concentration dependence of the electrical conductivity and diffusion permeability. The electrolyte used was a sodium chloride solution with a concentration range corresponding to the conditional composition of river water and the salinity of the Black Sea. During the research, it was found that samples of Ralex membranes of different batches have similar characteristics over the entire range of investigated concentrations. The calculated values of the transfer numbers for membranes of different batches differ insignificantly: ±0.01 for Ralex AMH in 1 M NaCl. For MK-40 and MA-41 membranes, a significant scatter of characteristics was found, especially in concentrated solutions. As a result, in 1 M NaCl, the transport numbers differ by ±0.05 for MK-40 and ±0.1 for MA-41. The value of the open circuit potential for the Ralex membrane pair showed that the experimental values of the potential are slightly lower than the theoretical ones. At the same time, the maximum calculated power density is higher than the experimental values. The maximum power density achieved in the experiment on reverse electrodialysis was 0.22 W/m2, which is in good agreement with the known literature data for heterogeneous membranes. The discrepancy between the experimental and theoretical data may be the difference in the characteristics of the membranes used in the reverse electrodialysis process from the tested samples and does not consider the shadow effect of the spacer in the channels of the electrodialyzer.
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Ion and Molecule Transport in Membrane Systems 2.0. Int J Mol Sci 2021; 22:ijms22073533. [PMID: 33805500 PMCID: PMC8036753 DOI: 10.3390/ijms22073533] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2021] [Accepted: 03/28/2021] [Indexed: 12/16/2022] Open
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