Effect of surface hydrophobization on chronopotentiometric behavior of an AMX anion-exchange membrane at overlimiting currents

Korzhova, E. N.; Pismenskaya, Natalia; Lopatin, D. A.; Baranov, O. V.; Dammak, L.; Nikonenko, Victor

doi:10.1016/j.memsci.2015.11.018

Cited by 61 publications

(50 citation statements)

References 62 publications

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“…Nanometer‐thick micrometer‐sized polyelectrolyte patterns transferred through microcontact printing on top of a membrane have the same effect on the emergence of electroosmotic induced fluid instabilities . Other works have shown that also hydrophobic surfaces lead to an intensified evolution of electroconvective vortices mixing the diffusion boundary layer . Through direct numerical simulations, we have recently discovered a complex chaotic mixing behavior induced by impermeable patches .…”

Section: Introductionmentioning

confidence: 77%

“…A drawback of the Sand equation is that it only takes the diffusive ion transport into account. It was already mathematically and experimentally shown that experimentally determined transition times are always larger than the ones obtained by the Sand equation . Thus, electroconvective flows may already promote the ion transfer even before the membrane surface is fully depleted.…”

Section: Methodsmentioning

confidence: 93%

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2D Patterned Ion‐Exchange Membranes Induce Electroconvection

Roghmans

Evdochenko

Stockmeier

et al. 2018

Adv Materials Inter

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Concentration polarization is a diffusion‐limited phenomenon for ion transport in electrodialysis based desalination processes. Once a so‐called limiting current is reached, the resistance of the system rises notably manifested as a plateau region in the current–voltage curves. For long it is hypothesized that altering the surface properties of the membrane can overcome the diffusional transport limitation by the induction of electroconvective vortices mixing the laminar boundary layer. To systematically investigate the influence of geometrical and chemical membrane surface topology on the evolution of electroconvection, circular patterns of polystyrene, poly(2‐vinylpyridine) (P2VP), and P2VP microgels are inkjet printed on cation‐exchange membranes. All types of patterns cause an insignificant increase in membrane resistance but they reduce the plateau lengths indicating the desired accelerated onset of electroconvection. In case of polystyrene (PS) patterns, the drop in plateau length results in a small reduction in transport resistance for overlimiting currents. However, membranes modified with linear P2VP and P2VP microgel patterns do exhibit a significantly decreased resistance in this region at a simultaneous increase of the limiting current density. Direct numerical simulations support the interpretation that the surface charge of the printed patterns influences the direction of the vortices being advantageous during ion transport toward the membrane.

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Section: Introductionmentioning

confidence: 77%

Section: Methodsmentioning

confidence: 93%

2D Patterned Ion‐Exchange Membranes Induce Electroconvection

Roghmans

Evdochenko

Stockmeier

et al. 2018

Adv Materials Inter

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“…2b) solutions, the limiting current found by graphical processing of the current-voltage curves obtained for t = 0 h slightly exceeds the value of calculated by Lévêque equation (4). The nature of this excess has been already discussed in [28]. It is due to the development of electroconvection via the mechanism of electroosmosis of the first kind.…”

Section: Evolution Of Current-voltage Characteristics Of the Membranesmentioning

confidence: 96%

“…In the case of an anion-exchange membrane in NaCl solution, the transport number of the salt counterion, T Cl , is related to the transport numbers of the coions T Na and water splitting products T OH by the following equation: (6) Our previous studies [28][29][30] showed that at reduced potential drops (10-50 mV) that correspond to reaching the limiting state, the T OH values in the AMX and AMX-Sb membranes are negligible. The T Cl value found for these (unexposed to electric current) membranes in a 0.02 M solution is 0.999.…”

Section: Transport Numbers Of Counterionsmentioning

confidence: 99%

“…The increase in the number and size of free-standing cavities in the order NaCl < NaH 2 PO 4 < KHT ( Table 2) leads to enhancement, in the same order, of electroconvection developing via the mechanism of electroosmosis of the first kind [35]: the tangential electric force applied to the electrical double layer on the inclined walls of the cavities generate small paired vortices [28,30,39]. These vortices deliver fluid on the outside of cavities into motion, reducing the diffusion layer thickness.…”

Section: Influence Of Membrane Surface Properties On Diffusion Layer mentioning

confidence: 99%

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Evolution of Current–Voltage Characteristics and Surface Morphology of Homogeneous Anion-Exchange Membranes during the Electrodialysis Desalination of Alkali Metal Salt Solutions

Rybalkina

Tsygurina

Сарапулова

et al. 2019

Membr. Membr. Technol.

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It has been found that after 300 h of operation of AMX and AMX-Sb anion-exchange membranes (Astom, Japan) in overlimiting current regimes in the process of electrodialysis desalination of 0.02 M NaCl, NH 4 Cl, NaH 2 PO 4 , and KC 4 H 5 O 6 (KHT) solutions, the limiting currents, , determined by graphic processing of current-voltage curves increase in the order NaCl < NaH 2 PO 4 < KHT. Their increments relative to those for the "fresh" membrane are 33, 90, and 128%, respectively. The growth in is accompanied by an increase in the thickness of the samples occurring in the NaH 2 PO 4 and KHT solutions. In the case of NH 4 Cl, the values of decrease. It has been shown that a small decrease in counterion transport numbers during membrane operation has almost no effect on the values of limiting currents. The main contribution to the increase in is apparently made by electroconvection, which develops according to the mechanism of electroosmosis of the first kind. Its development is facilitated by the growth in the number and size of freestanding micrometer-sized cavities on the surface of anion-exchange membranes, the area and linear dimensions of which increase in the order NaCl < NaH 2 PO 4 < KHT. These cavities are formed as a result of enhancement of electrochemical degradation of the ion-exchange material and the inert filler polyvinyl chloride at the membrane/solution interface in ampholyte solutions.

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Surface modification of ion‐exchange membranes: Methods, characteristics, and performance

Khoiruddin

Ariono

Subagjo

et al. 2017

J of Applied Polymer Sci

109

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Considerable effort has been made to improve ion-exchange membrane (IEM) properties in order to achieve better performance of IEM-based processes in various applications. Surface modification is one of the effective ways to improve IEM properties. Various methods have been used to modify IEM surfaces, for example, plasma treatment, polymerization, solution casting, electrodeposition, and ion implantation. These methods are able to produce a thin and fine distributed layer and also to modify the chemical structure of the surface. The new layer can be adsorbed, deposited, or chemically bonded on a membrane surface. By using these methods, IEM properties are improved, and the desired or specific characteristics such as high monovalent ion permselectivity, low fuel crossover, and anti-organic-fouling property can be obtained. In this paper, methods for surface modification of IEMs are reviewed. Moreover, the effects of modification on IEM properties and performance are discussed.

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Effect of surface hydrophobization on chronopotentiometric behavior of an AMX anion-exchange membrane at overlimiting currents

Cited by 61 publications

References 62 publications

2D Patterned Ion‐Exchange Membranes Induce Electroconvection

2D Patterned Ion‐Exchange Membranes Induce Electroconvection

Evolution of Current–Voltage Characteristics and Surface Morphology of Homogeneous Anion-Exchange Membranes during the Electrodialysis Desalination of Alkali Metal Salt Solutions

Surface modification of ion‐exchange membranes: Methods, characteristics, and performance

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