Effect of fixed charge group concentration on salt permeability and diffusion coefficients in ion exchange membranes

Kamcev, Jovan; Doherty, Cara M.; Lopez, Kian P.; Hill, Anita J.; Paul, Donald R; Freeman, Benny D.

doi:10.1016/j.memsci.2018.08.053

Cited by 42 publications

(32 citation statements)

References 55 publications

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“…Of course, this to some extent limits the selectivity of such materials. Note that this approach leads to a paradoxical for other types of ion-exchange membranes effect—an increase in the functional group concentration in these membranes leads to a decrease in water uptake per functional group and an increase in selectivity [ 168 , 170 , 171 ].…”

Section: Cross-linking Of Polymer Membranesmentioning

confidence: 99%

Selectivity of Transport Processes in Ion-Exchange Membranes: Relationship with the Structure and Methods for Its Improvement

Стенина

Голубенко

Nikonenko

et al. 2020

IJMS

124

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Nowadays, ion-exchange membranes have numerous applications in water desalination, electrolysis, chemistry, food, health, energy, environment and other fields. All of these applications require high selectivity of ion transfer, i.e., high membrane permselectivity. The transport properties of ion-exchange membranes are determined by their structure, composition and preparation method. For various applications, the selectivity of transfer processes can be characterized by different parameters, for example, by the transport number of counterions (permselectivity in electrodialysis) or by the ratio of ionic conductivity to the permeability of some gases (crossover in fuel cells). However, in most cases there is a correlation: the higher the flux density of the target component through the membrane, the lower the selectivity of the process. This correlation has two aspects: first, it follows from the membrane material properties, often expressed as the trade-off between membrane permeability and permselectivity; and, second, it is due to the concentration polarization phenomenon, which increases with an increase in the applied driving force. In this review, both aspects are considered. Recent research and progress in the membrane selectivity improvement, mainly including a number of approaches as crosslinking, nanoparticle doping, surface modification, and the use of special synthetic methods (e.g., synthesis of grafted membranes or membranes with a fairly rigid three-dimensional matrix) are summarized. These approaches are promising for the ion-exchange membranes synthesis for electrodialysis, alternative energy, and the valuable component extraction from natural or waste-water. Perspectives on future development in this research field are also discussed.

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Section: Cross-linking Of Polymer Membranesmentioning

confidence: 99%

Selectivity of Transport Processes in Ion-Exchange Membranes: Relationship with the Structure and Methods for Its Improvement

Стенина

Голубенко

Nikonenko

et al. 2020

IJMS

124

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“…The value of t 1 differs little from 1 in a wide range of concentrations. Therefore, co-ions make the decisive contribution to the value of P. Theoretical estimates [20,56,58,59] and experimental results [52,58] allow concluding that c A /c A << 1, and D A is one or two orders of magnitude smaller than the diffusion coefficient in the external solution. With increasing f 2 , the volume fraction of the solution, which is equivalent to the external solution, increases.…”

Section: Diffusion Permeability Of Membranes In Solutions Of Differenmentioning

confidence: 99%

“…It is known that the permselectivity of membranes is mainly determined by their electrical conductivity and diffusion permeability [18][19][20][21]. It was shown in [22][23][24] that the electrical conductivity of anion-exchange membranes (AEM) and cation-exchange membranes (CEM) can remain almost the same or grow with diluting solutions of phosphoric, carboxylic, or amino acid salts.…”

Section: Introductionmentioning

confidence: 99%

Concentration Dependencies of Diffusion Permeability of Anion-Exchange Membranes in Sodium Hydrogen Carbonate, Monosodium Phosphate, and Potassium Hydrogen Tartrate Solutions

et al. 2019

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The concentration dependencies of diffusion permeability of homogeneous (AMX-Sb and AX) and heterogeneous (MA-41 and FTAM-EDI) anion-exchange membranes (AEMs) is obtained in solutions of ampholytes (sodium bicarbonate, NaHCO3; monosodium phosphate, NaH2PO4; and potassium hydrogen tartrate, KHT) and a strong electrolyte (sodium chloride, NaCl). It is established that the diffusion permeability of AEMs increases with dilution of the ampholyte solutions, while it decreases in the case of the strong electrolyte solution. The factors causing the unusual form of concentration dependencies of AEMs in the ampholyte solutions are considered: (1) the enrichment of the internal AEM solution with multiply charged counterions and (2) the increase in the pore size of AEMs with dilution of the external solution. The enrichment of the internal solution of AEMs with multiply charged counterions is caused by the Donnan exclusion of protons, which are the products of protolysis reactions. The increase in the pore size is conditioned by the stretching of the elastic polymer matrix due to the penetration of strongly hydrated anions of carbonic, phosphoric, and tartaric acids into the AEMs.

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“…The permselectivity is largely determined by the ability of the membranes to displace the co‐ions due to electrostatic repulsion between the similarly charged walls of pores or channels—the so‐called Donnan effect. According to the Donnan theory, the higher the concentration of functional groups in the inner pore volume (C inn ), the more efficient is such displacement . The C inn parameter is equal to the molar quantity of functional groups per kilogram of the water absorbed by a membrane and is inversely proportional to the water numbers.…”

Section: Resultsmentioning

confidence: 99%

Novel anion exchange membrane with low ionic resistance based on chloromethylated/quaternized‐grafted polystyrene for energy efficient electromembrane processes

Голубенко

Bruggen

Yaroslavtsev

2019

J of Applied Polymer Sci

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A novel anion-exchange membrane has been manufactured by chloromethylation and subsequent quaternization of polystyrene within a graft copolymer films based on UV-oxidized polymethylpentene. Particular attention is given to the kinetics of chloromethylation and the influence of the reaction conditions on the properties of the anion-exchange membranes. By means of variation of the polystyrene content and its crosslinking degree we have obtained membranes that have an ion-exchange capacity from 1.1 to 2.9 mmole g −1 , anion transport numbers between 91.0 and 95.5% and specific ionic conductivities (σ 25Cl − Þ ranging from 2 to 25 mS cm −1 . The developed membranes due to their low thickness and high conductivities have a remarkably low surface ionic resistance of around 0.6 Ω cm 2 . It was calculated that the use of the developed materials will increase the efficiency of reverse electrodialysis energy production by 8-10% compared to the state of the art membranes.

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Effect of fixed charge group concentration on salt permeability and diffusion coefficients in ion exchange membranes

Cited by 42 publications

References 55 publications

Selectivity of Transport Processes in Ion-Exchange Membranes: Relationship with the Structure and Methods for Its Improvement

Selectivity of Transport Processes in Ion-Exchange Membranes: Relationship with the Structure and Methods for Its Improvement

Concentration Dependencies of Diffusion Permeability of Anion-Exchange Membranes in Sodium Hydrogen Carbonate, Monosodium Phosphate, and Potassium Hydrogen Tartrate Solutions

Novel anion exchange membrane with low ionic resistance based on chloromethylated/quaternized‐grafted polystyrene for energy efficient electromembrane processes

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