Enhancement of Mass Transfer Through a Homogeneous Anion-Exchange Membrane in Limiting and Overlimiting Current Regimes by Screening Part of Its Surface with Nonconductive Strips

Nebavskaya, K. A.; Butylskii, D. Yu.; Moroz, Ilya A.; Nebavsky, Andrey; Pismenskaya, Natalia; Nikonenko, Victor

doi:10.1134/s0965544118090086

Cited by 17 publications

(16 citation statements)

References 28 publications

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“…According to these estimates, the optimal surface fraction occupied by nonconductive regions is about 10%. The same value of Sscr for the best electrically heterogeneous membranes was also experimentally determined by Nebavskaya et al [40]. Note that the theoretical optimum value of Sscr estimated by Davidson et al [38] was approximately equal to 50%.…”

Section: Impact Of the Membrane Modification On The Electrochemical Psupporting

confidence: 77%

“…In a number of theoretical and experimental studies [38][39][40][41], it was shown that the presence of electrical inhomogeneity on the IEM surface leads to an increase in the intensity of EC. At the same time, the electrical inhomogeneity of the surface also causes negative effects, namely, an increase in the concentration polarization of the solution near the conducting regions of the surface.…”

Section: Introductionmentioning

confidence: 99%

“…However, too much shielded surface results in the reduction of mass transfer compared to the homogeneous membrane. Nebavskaya et al [40] modified homogeneous Neosepta AMX-Sb membranes by deposition of nonconductive strips (parallel to each other) of styrene polyacrylate on their surface. A 2D laser printer was used for the deposition of the strips.…”

Section: Introductionmentioning

confidence: 99%

“…Despite the fact that some aspects of the effect of electrical inhomogeneity parameters (mainly, the fraction of the screened surface) on the mass transfer rate were studied [21,39], there has not been any real optimization of the surface parameters. Note, that influence of the size of nonconducting regions and the distance between them were considered only in [40]. However, only one type of surface geometry was studied in this paper: alternating conductive and nonconductive strips.…”

Section: Introductionmentioning

confidence: 99%

“…For the first time, we make an attempt to find the optimal parameters of the surface electrical heterogeneity when considering 13 different membrane samples. We carry out this study on a wider range of screened surface fraction values than in [21,40] when applying round, square, and rectangular low conductive spots. The use of stencils made it possible to specify the geometry of the spots with a high accuracy, in contrast to [21], in which the nonconducting material was randomly deposited on the membrane surface.…”

Section: Introductionmentioning

confidence: 99%

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How Electrical Heterogeneity Parameters of Ion-Exchange Membrane Surface Affect the Mass Transfer and Water Splitting Rate in Electrodialysis

Zyryanova

Mareev

Gil

et al. 2020

IJMS

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Electrodialysis (ED) has been demonstrated as an effective membrane method for desalination, concentration, and separation. Electroconvection (EC) is a phenomenon which can essentially increase the mass transfer rate and reduce the undesirable water splitting effect. Efforts by a number of researchers are ongoing to create conditions for developing EC, in particular, through the formation of electrical heterogeneity on the membrane surface. We attempt, for the first time, to optimize the parameters of surface electrical heterogeneity for ion-exchange membranes used in a laboratory ED cell. Thirteen different patterns on the surface of two Neosepta anion-exchange membranes, AMX and AMX-Sb, were tested. Low-conductive fluoropolymer spots were formed on the membrane surface using the electrospinning technique. Spots in the form of squares, rectangles, and circles with different sizes and distances between them were applied. We found that the spots’ shape did not have a visible effect. The best effect, i.e., the maximum mass transfer rate and the minimum water splitting rate, was found when the spots’ size was close to that of the diffusion layer thickness, δ (about 250 μm in the experimental conditions), and the distance between the spots was slightly larger than δ, such that the fraction of the screened surface was about 20%.

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Section: Impact Of the Membrane Modification On The Electrochemical Psupporting

confidence: 77%