Novel ionic separation mechanisms in electrically driven membrane processes

Wenten, I Gede; Khoiruddin, Khoiruddin; Alkhadra, Mohammad A.; Tian, Huanhuan; Bazant, Martin Z.

doi:10.1016/j.cis.2020.102269

Cited by 45 publications

(17 citation statements)

References 94 publications

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“…According to the World Health Organization, only 7 out of 10 people used safely managed water in 2015, 1 which highlights the importance of developing and improving technologies for desalination, decontamination, and disinfection of water 2 . Shock electrodialysis (ED) is a recently proposed water treatment technology 3 based on the mechanism of deionization shock waves in charged porous media 4 and microchannels, 5,6 and initial results have shown its capability for deionization, filtration, separation, and disinfection 7‐9 . Compared with traditional technologies like reverse osmosis, thermal distillation, and ED, shock ED is scalable, continuous, efficient at low ionic strength, 3 and potentially membrane‐free.…”

Section: Introductionmentioning

confidence: 99%

Deionization shocks in crossflow

et al. 2021

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Shock electrodialysis is a recently developed electrochemical water treatment method that shows promise for water deionization and ionic separations. Although simple models and scaling laws have been proposed, a predictive theory has not yet emerged to fit experimental data and enable system design. Here, we extend and analyze existing “leaky membrane” models for the canonical case of a steady shock in crossflow, as in recent experimental prototypes. Two‐dimensional numerical solutions are compared with analytical boundary‐layer approximations and experimental data. The boundary‐layer theory accurately reproduces the simulation results for desalination, and both models predict the data collapse of the desalination factor with dimensionless current, scaled to the incoming convective flux of cations. The numerical simulation also predicts the water recovery increase with current. Nevertheless, neither approach can quantitatively fit the transition from normal to over‐limiting current, which suggests gaps in our understanding of extreme electrokinetic phenomena in porous media.

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Section: Introductionmentioning

confidence: 99%

Deionization shocks in crossflow

et al. 2021

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“…Interest in EC is quite justified because this phenomenon can provide a significant increase in the mass transfer in overlimiting current modes [40], making it possible to propose new devices for the desalination of multicomponent and dilute solutions [42,49], as well as preventing or strongly reducing scaling in the electrodialysis demineralization of multicomponent liquid media in the food industry [41,50]. Evidence of EC development in the presence of phosphoric acid anions, EDTA, heavy metal hydroxides, citrates, tartrates, and other ampholytes is revealed in investigations carried out by the groups of Pérez-Herranz and Bernardes [12,23,25,34,51], as well as Bazinet [32,[50][51][52].…”

Section: Introductionmentioning

confidence: 99%

Influence of Electroconvection on Chronopotentiograms of an Anion-Exchange Membrane in Solutions of Weak Polybasic Acid Salts

Pismenskaya

Rybalkina

Moroz

et al. 2021

IJMS

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Visualization of electroconvective (EC) vortices at the undulated surface of an AMX anion-exchange membrane (Astom, Osaka, Japan) was carried out in parallel with the measurement of chronopotentiograms. Weak polybasic acid salts, including 0.02 M solutions of tartaric (NaHT), phosphoric (NaH2PO4), and citric (NaH2Cit) acids salts, and NaCl were investigated. It was shown that, for a given current density normalized to the theoretical limiting current calculated by the Leveque equation (i/ilimtheor), EC vortex zone thickness, dEC, decreases in the order NaCl > NaHT > NaH2PO4 > NaH2Cit. This order is inverse to the increase in the intensity of proton generation in the membrane systems under study. The higher the intensity of proton generation, the lower the electroconvection. This is due to the fact that protons released into the depleted solution reduce the space charge density, which is the driver of EC. In all studied systems, a region in chronopotentiograms between the rapid growth of the potential drop and the attainment of its stationary values corresponds to the appearance of EC vortex clusters. The amplitude of the potential drop oscillations in the chronopotentiograms is proportional to the size of the observed vortex clusters.

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“…According to the World Health Organization, only seven out of ten people used safely managed water in 2015 [1], which highlights the importance of developing or improving technologies for desalination, decontamination, and disinfection of water [2]. Shock electrodialysis (ED) is a recently proposed water treatment technology [3], based on the mechanism of deionization shock waves in charged porous media [4] and microchannels [5,6], and primary results have shown its capability for deionization, filtration, separation, and disinfection [7][8][9]. Compared with traditional technologies like reverse osmosis, thermal distillation, and electrodialysis, shock electrodialysis is scalable, continuous, potentially membrane free, and efficient at low ionic strength [3].…”

Section: Introductionmentioning

confidence: 99%

Deionization Shocks in Crossflow

Schlumpberger,

Smith,

Tian

et al. 2020

Preprint

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Shock electrodialysis is a recently developed electrochemical water treatment method which shows promise for water deionization and ionic separations. Although simple models and scaling laws have been proposed, a predictive theory has not yet emerged to fit experimental data and enable system design. Here, we extend and analyze existing "leaky membrane" models for the canonical case of a steady shock in cross flow, as in recent experimental prototypes. Two-dimensional numerical solutions are compared with analytical boundary-layer approximations and experimental data.The boundary-layer theory accurately reproduces the simulation results for desalination, and both models predict the data collapse of the desalination factor with dimensionless current, scaled to the incoming convective flux of cations. The numerical simulation also predicts the water recovery increase with current. Nevertheless, both approaches cannot quantitatively fit the transition from normal to over-limiting current, which suggests gaps in our understanding of extreme electrokinetic phenomena in porous media.

show abstract

Novel ionic separation mechanisms in electrically driven membrane processes

Cited by 45 publications

References 94 publications

Deionization shocks in crossflow

Deionization shocks in crossflow

Influence of Electroconvection on Chronopotentiograms of an Anion-Exchange Membrane in Solutions of Weak Polybasic Acid Salts

Deionization Shocks in Crossflow

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