Effect of the sulfocation-exchanger dispersity on the surface morphology, microrelief of heterogeneous membranes and development of electroconvection in intense current modes

Акберова, Э. М.; Васильева, В. И.; Zabolotsky, V. I.; Novák, Luboš

doi:10.1016/j.memsci.2018.08.042

Cited by 29 publications

(18 citation statements)

References 45 publications

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“…Prior to experiments, the membrane samples were treated with NaCl solutions with different concentrations [10].…”

Section: Membranesmentioning

confidence: 99%

“…In the electrochemical behavior of heterogeneous ion-exchange membranes, the electrical inhomogeneity of their surface, consisting ofthe presence of the regions with high (ion-exchanger phase) and low (polyethylene phase) conductivity, plays an important role. In [1][2][3][4][5][6][7][8][9][10], the possibility of mass transfer intensification in an electromembrane system by improving the morphology of the surface of ion-exchange membranes was demonstrated. The use of membranes with optimized surface morphology in the process of electrodialysis for desalting and deionization of natural waters and technological solutions creates the prerequisites for a significant increase in the efficiency of these processes in the limiting and overlimiting current modes.…”

Section: Introductionmentioning

confidence: 99%

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A Study of Ralex Membrane Morphology by SEM

et al. 2019

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A comparative analysis of the effect of the manufacturing technology of heterogeneousion-exchange membranes Ralex CM Pes manufactured by MEGA a.s. (Czech Republic) on the structural properties of their surface and cross section by SEM was carried out. The CM Pes membrane is a composite of a sulfonated ion-exchanger with inert binder of polyethylene and reinforcing polyester fiber. In the manufacture of membranes Ralex the influence of two factors was investigated. First, the time of ion-exchange grain millingvaried at a constant resin/polyethylene ratio. Second, the ratio of the cation-exchanger and the inert binder of polyethylene varied. It has been found that the membrane surface becomes more electrically homogeneous with the growth of the ion-exchanger loading and a decrease in its particle size. With an increase in the milling time of resin grainsfrom 5 to 80 min a more than 1.5-fold decrease in their radius and in the distance between them was revealed.Besides, there is a 1.5-fold decrease in the fraction, as well as in the size of pores and structure defects. The fraction of the ion-exchange phase on the membrane surface decreases by 7%. With an increase in the resin loading from 45 to 70 wt %, the growth of the fraction of conducting regions on the surface is almost twofold, while their sizes remain practically unchanged. More significant changes in the surface structure of the studied membranes are established in comparison with the cross section. An increase in the resin content in the membranes from 45 to 70 wt % corresponds to a 43% increment of its fraction on the cross-section.The increase in the ion-exchanger content of Ralex membranes is accompanied by the growth of the fraction of macropores and structure defects on the membrane surface by 70% and a twofold decrease in the distance between conducting zones.

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“…Prior to experiments, the membrane samples were treated with NaCl solutions with different concentrations [10].…”

Section: Membranesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

A Study of Ralex Membrane Morphology by SEM

et al. 2019

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“…The closest analog of this membrane is the Ralex-CMH membrane produced by MEGA a.s. (Straz pod Ralskem, Czech Republic). The properties of the MK-40 membrane are described elsewhere, for example in [ 32 , 33 , 34 , 35 , 36 ]. The MK-40/PANI membrane is obtained by synthesizing PANI on the surface of the MK-40 membrane under conditions of electrodiffusion of the monomer and the oxidizer in an external electric field [ 37 ].…”

Section: Methodsmentioning

confidence: 99%

Influence of Surface Modification of MK-40 Membrane with Polyaniline on Scale Formation under Electrodialysis

et al. 2020

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A comprehensive study of the polyaniline influence on mineral scaling on the surface of the heterogeneous MK-40 sulfocationite membrane under electrodialysis has been conducted. Current-voltage curves and chronopotentiograms have been obtained and analyzed for the pristine MK-40 membrane and the MK-40 membrane which is surface-modified by polyaniline. The study of the electrochemical behavior of membranes has been accompanied by the simultaneous control of the pH of the solution outcoming from the desalination compartment. The mixture of Na2CO3, KCl, CaCl2, and MgCl2 is used as a model salt solution. Two limiting states are observed on the current-voltage curve of the surface-modified membrane. There is the first pseudo-limiting state in the range of small values of the potential drop. The second limiting current is comparable with that of the limiting current for the pristine membrane. It is shown that chronopotentiometry cannot be used as a self-sufficient method for membrane scaling identification on the surface-modified membrane at high currents. A mineral scale on the surfaces of the studied membranes has been found by scanning electron microscopy. The amount of precipitate is higher in the case of the surface-modified membrane compared with the pristine one.

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“…Cation-exchange membranes based on polystyrenesulfonic acid are commonly used in various water treatment methods [11]. To improve the mechanical properties, these materials are used in the form of heterogeneous membranes with a plasticizer, which is typically polyethylene.…”

Section: Introductionmentioning

confidence: 99%

“…To improve the mechanical properties, these materials are used in the form of heterogeneous membranes with a plasticizer, which is typically polyethylene. Cation-exchange membranes MK-40, which are commonly used in water treatment, are produced in Russia [11][12][13]. Their analogue Ralex CM-is produced in the Czech Republic by MEGA a.s. company [14].…”

Section: Introductionmentioning

confidence: 99%

Effect of Modification with Cesium Acid Salt of Phosphotungstic Acid on the Properties of Membranes Based on Grafted Sulfonated Polystyrene

Прихно

Yaroslavtsev

Голубенко

2019

Membr. Membr. Technol.

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The possibility of modification of ion-exchange membranes with high pore and channel volumes and the effect of doping on the membrane properties have been studied. Hybrid membranes based on sulfonated polystyrene grafted onto polymethylpentene and cesium acid phosphotungstate have been synthesized by the in situ method. It has been shown that modification of these membranes leads to an increase in conductivity to 34.8 mS/cm at 25°С in contact with water. The chloride anion transport numbers for the original and modified membranes are about 4%.

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Effect of the sulfocation-exchanger dispersity on the surface morphology, microrelief of heterogeneous membranes and development of electroconvection in intense current modes

Cited by 29 publications

References 45 publications

A Study of Ralex Membrane Morphology by SEM

A Study of Ralex Membrane Morphology by SEM

Influence of Surface Modification of MK-40 Membrane with Polyaniline on Scale Formation under Electrodialysis

Effect of Modification with Cesium Acid Salt of Phosphotungstic Acid on the Properties of Membranes Based on Grafted Sulfonated Polystyrene

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