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Wang Q, Chun J, Subban CV. Influence of Concentration Gradients on Electroconvection at a Cation-Exchange Membrane Surface. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2024; 40:1613-1622. [PMID: 38181224 DOI: 10.1021/acs.langmuir.3c02453] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2024]
Abstract
Membrane-based systems, such as electrodialysis, play an important role in desalination and industrial separation processes. Electrodialysis uses alternating anion- and cation-exchange membranes with a perpendicular electric field to generate concentrated and diluate streams from a feed solution. It is known that under overlimiting current conditions, reduced charge and mass transfer at the membrane interface leads to regions of high ion depletion generating instability and vortices termed electroconvection. While electroconvective mixing is known to directly impact the separation efficiency of electrodialysis, the influence of ion concentration gradients across the membrane experienced in a functional electrodialysis system is not known. Here, we report the influence of ion concentration gradients across a cation exchange membrane (Nafion) that is both aligned with and opposed to the applied electric field. Experiments were conducted by coflowing NaCl solutions of different concentrations (0.1-100 mM) on each side of the membrane, and electroconvection was visualized with a fluorescence dye (Rhodamine 6G). We obtained concentration profiles from fluorescence image data and systematically measured the thickness of the depletion boundary layer dBL under different conditions. We found smaller dBL values at a higher flow rate both with and without concentration gradients. Our results show that electroconvection is enhanced when the electric field is opposite to the direction of the concentration gradient.
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Affiliation(s)
- Qingpu Wang
- Energy and Environment Directorate, Pacific Northwest National Laboratory, Seattle, Washington 98109, United States
| | - Jaehun Chun
- Physical and Computational Sciences Directorate, Pacific Northwest National Laboratory, Richland, Washington 99354, United States
| | - Chinmayee V Subban
- Energy and Environment Directorate, Pacific Northwest National Laboratory, Seattle, Washington 98109, United States
- Department of Materials Science and Engineering, University of Washington, Seattle, Washington 98195, United States
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2
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Seo J, Jung S, Park J, Kim HY, Kim SJ. Hierarchical Capillarity-Assisted Liquid Invasion in Multilayered Paper Channels for Nanoelectrokinetic Preconcentration. NANO LETTERS 2023; 23:8065-8072. [PMID: 37581872 DOI: 10.1021/acs.nanolett.3c02044] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/16/2023]
Abstract
A nanoelectrokinetic phenomenon called ion concentration polarization (ICP) has been recently applied to microfluidic paper-based devices for the high fold preconcentration of low-abundant analytes. The inherent microstructural characteristics of cellulose papers can sufficiently stabilize the chaotic electroconvection of ICP, which is a significant annoyance for typical engineered microfluidic channels. However, a high electrical voltage to induce ICP in a paper-fluidic channel can increase unavoidable electrophoretic forces over drag forces so that the preconcentrated plug is rapidly receded with severe dispersion. In order to enhance the hydraulic drag force that helps the preconcentration of analytes, here we introduce a multilayered paper structure into paper-fluidic channel. We theoretically and experimentally demonstrate that a hierarchical capillary structure in a multilayered paper-fluidic channel can effectively increase the hydraulic drag force. For the practical utility in the field of diagnostics, the mechanism is verified by a simple example of the immunoassay using biotin-streptavidin complexation.
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Affiliation(s)
- Joowon Seo
- Department of Electrical and Computer Engineering, Seoul National University, Seoul 08826, Republic of Korea
| | - Sohyun Jung
- Department of Mechanical Engineering, Seoul National University, Seoul 08826, Republic of Korea
| | - Jihee Park
- Department of Electrical and Computer Engineering, Seoul National University, Seoul 08826, Republic of Korea
| | - Ho-Young Kim
- Department of Mechanical Engineering, Seoul National University, Seoul 08826, Republic of Korea
- SOFT Foundry Institute, Seoul National University, Seoul 08826, Republic of Korea
- Institute of Advanced Machines and Design, Seoul National University, Seoul 08826, Republic of Korea
| | - Sung Jae Kim
- Department of Electrical and Computer Engineering, Seoul National University, Seoul 08826, Republic of Korea
- SOFT Foundry Institute, Seoul National University, Seoul 08826, Republic of Korea
- Inter-university Semiconductor Research Center, Seoul National University, Seoul 08826, Republic of Korea
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3
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Sharma A, Mukherjee A, Warren A, Jin S, Li G, Koch DL, Archer LA. Electroconvective Flow in Liquid Electrolytes Containing Oligomer Additives. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2023; 39:92-100. [PMID: 36549330 DOI: 10.1021/acs.langmuir.2c02210] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Metal electrodeposition in batteries is fundamentally unstable and affected by different instabilities depending on operating conditions and electrolyte chemistry. Particularly, at high charging rates, a hydrodynamic instability loosely termed electroconvection sets in, which complicates all electrochemical processes by creating a nonuniform ion flux and preferential deposition at the electrode. Here, we isolate and study electroconvection by experimentally investigating how oligomer additives in liquid electrolytes interact with the hydrodynamic instability at a cation selective interface. From electrochemical measurements and direct visualization experiments, we find that electroconvection is delayed and suppressed at all voltages in the presence of oligomers. The underlying mechanism is revealed to involve formation of an oligomer ad-layer at the interface, which in response to perturbation is believed to exert an opposing body force on the surrounding fluid to preserve the ad-layer structure and in so doing suppresses electroconvection. Our results therefore reveal that in battery electrolytes without obvious sources of bulk elasticity, surface forces produced by adsorbed polymers can be used to advantage for suppressing instability.
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Affiliation(s)
- Arpita Sharma
- School of Chemical and Biomolecular Engineering, Cornell University, Ithaca, New York14853, United States
| | - Ankush Mukherjee
- School of Mechanical and Aerospace Engineering, Cornell University, Ithaca, New York14853, United States
| | - Alexander Warren
- School of Chemical and Biomolecular Engineering, Cornell University, Ithaca, New York14853, United States
| | - Shuo Jin
- School of Chemical and Biomolecular Engineering, Cornell University, Ithaca, New York14853, United States
| | - Gaojin Li
- School of Chemical and Biomolecular Engineering, Cornell University, Ithaca, New York14853, United States
| | - Donald L Koch
- School of Chemical and Biomolecular Engineering, Cornell University, Ithaca, New York14853, United States
| | - Lynden A Archer
- School of Chemical and Biomolecular Engineering, Cornell University, Ithaca, New York14853, United States
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4
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Uzdenova A, Kovalenko A, Urtenov M. Theoretical Analysis of Electroconvection in the Electrodialysis Desalination Channel under the Action of Direct Current. MEMBRANES 2022; 12:membranes12111125. [PMID: 36363680 PMCID: PMC9697486 DOI: 10.3390/membranes12111125] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/25/2022] [Revised: 11/07/2022] [Accepted: 11/08/2022] [Indexed: 05/12/2023]
Abstract
The development of electroconvection in electromembrane systems is a factor that increases the efficiency of the electrolyte solution desalination process. The desalination of the solution, manifested by a change in the distribution of the ion concentration, can affect the mechanisms of development of electroconvection. The purpose of this work is to study the electroconvective flow developing in the desalination channel under various desalination scenarios. The study was carried out on the basis of a mathematical model of the transfer of binary electrolyte ions in the desalination channel formed between the anion and cation exchange membranes under the action of DC current. An analytical estimation of the threshold current density reflecting the conditions of the system transition into a quasi-stationary state has been obtained. The chronopotentiograms of the desalination channel and the thickness of the electroconvective mixing layer are calculated for both pre-threshold and supra-threshold values of the current density.
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Affiliation(s)
- Aminat Uzdenova
- Department of Computer Science and Computational Mathematics, Umar Aliev Karachai-Cherkess State University, 369202 Karachaevsk, Russia
| | - Anna Kovalenko
- Department of Data Analysis and Artificial Intelligence, Kuban State University, 350040 Krasnodar, Russia
- Correspondence:
| | - Makhamet Urtenov
- Department of Applied Mathematics, Kuban State University, 350040 Krasnodar, Russia
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5
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Measurement of Electrokinetically induced hydrodynamics at Ion-selective interfaces using 3D Micro particle tracking velocimetry (µPTV). MethodsX 2022; 9:101814. [PMID: 36046738 PMCID: PMC9421390 DOI: 10.1016/j.mex.2022.101814] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Accepted: 08/04/2022] [Indexed: 11/23/2022] Open
Abstract
Electrokinetic flow phenomena are ubiquitous in electrical systems for desalination, chemical conversion, or mixing at a micro-scale. However, the important features of resulting 3D flow fields are only accessible through cost-intensive numerical simulations. Experimental 2D recording of the chaotic three-dimensional velocity fields developing for example at currents exceeding the limiting current density does not capture the complex 3D structures present in such flow fields. Additionally, numerical 3D studies are limited to dimensions three orders of magnitude smaller as found in real applications and only short run times due to the enormous computational effort. To apply the theoretical knowledge in real-world systems and create the possibility for detailed parameter studies, we present the first experimental method for recording and quantifying the time-resolved velocity field in an electrochemical microfluidic cell in 3D with dimensions found in industrial applications. We utilize this method in a co-submitted paper to record the 3D velocity field of electroconvection at a cation-exchange membrane.Cell design suitable for simultaneous electrochemical experiments with optical 3D velocity quantification Method optimized for velocity reconstruction of membrane-to-membrane distances found in industrial cells Highly adaptable cell design, for optical characterization of electrochemical systems
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6
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The effects of reaction kinetics upon the instabilities in cathodic electrodeposition. Curr Opin Colloid Interface Sci 2022. [DOI: 10.1016/j.cocis.2022.101591] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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7
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Kochmann S, Ivanov NA, Le Blanc JCY, Gorin BI, Krylov SN. Circular Geometry in Molecular Stream Separation to Facilitate Nonorthogonal Field-to-Flow Orientation. Anal Chem 2022; 94:9519-9524. [PMID: 35767324 DOI: 10.1021/acs.analchem.2c01829] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Molecular stream separation (MSS) is a promising complement for continuous-flow synthesis. MSS is driven by forces exerted on molecules by a field applied at an angle to the stream-carrying flow. MSS has only been performed with a 90° field-to-flow angle because of a rectangular geometry of canonic MSS; the second-order rotational symmetry of a rectangle prevents any other angle. Here, we propose a noncanonic circular geometry for MSS, which better aligns with the polar nature of MSS and allows changing the field-to-flow. We conducted in silico and experimental studies of circular geometry for continuous-flow electrophoresis (CFE, an MSS method). We proved two advantages of circular CFE over its rectangular counterpart. First, circular CFE can support better flow and electric-field uniformity than rectangular CFE. Second, the nonorthogonal field-to-flow orientation, achievable in circular CFE, can result in a higher stream resolution than the orthogonal one. Considering that circular CFE devices are not more complex in fabrication than rectangular ones, we foresee that circular CFE will serve as a new standard and a testbed for the investigation and creation of new CFE modalities.
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Affiliation(s)
- Sven Kochmann
- Department of Chemistry and Centre for Research on Biomolecular Interactions, York University, 4700 Keele Street, Toronto, Ontario M3J 1P3, Canada
| | - Nikita A Ivanov
- Department of Chemistry and Centre for Research on Biomolecular Interactions, York University, 4700 Keele Street, Toronto, Ontario M3J 1P3, Canada
| | | | - Boris I Gorin
- Eurofins CDMO Alphora, 2395 Speakman Drive #2001, Mississauga, Ontario L5K 1B3, Canada
| | - Sergey N Krylov
- Department of Chemistry and Centre for Research on Biomolecular Interactions, York University, 4700 Keele Street, Toronto, Ontario M3J 1P3, Canada
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8
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Electroconvective instability and shocks in complex geometries. Curr Opin Colloid Interface Sci 2022. [DOI: 10.1016/j.cocis.2022.101604] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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9
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Lee D, Choi D, Park H, Lee H, Kim SJ. Electroconvective circulating flows by asymmetric Coulombic force distribution in multiscale porous membrane. J Memb Sci 2021. [DOI: 10.1016/j.memsci.2021.119286] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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10
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Space-Charge breakdown phenomenon and spatio-temporal ion concentration and fluid flow patterns in overlimiting current electrodialysis. J Memb Sci 2021. [DOI: 10.1016/j.memsci.2021.119583] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
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11
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Chen D, Kim JT, Chamorro LP, Timperman AT. Exceeding ohmic scaling by more than one order of magnitude with a 3D ion concentration polarization system. LAB ON A CHIP 2021; 21:3094-3104. [PMID: 34259277 PMCID: PMC9680042 DOI: 10.1039/d1lc00470k] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
We report an ion concentration polarization (CP) system that exceeds ohmic scaling, a barrier that has stood for more than four decades, by more than one order of magnitude. CP is used in many important applications, including the enrichment of trace analytes in microfluidic systems and water purification by electrodialysis. The mechanisms that control the current through these systems have been largely discovered, but the reduced currents and loss of efficiency imparted by the high resistance of the CP ion depleted zone have not been overcome. To obtain high currents, an ion permselective element with a microscale cross-section is interfaced with a macroscale reservoir. Confocal fluorescence microscopy and microparticle tracking velocimetry (μ-PTV) are used to characterize the depleted zone that emanates vertically from the CP inducing nanoporous gel into the macroscale reservoir. The shape and growth of the depleted zone and velocity in the surrounding bulk solution are consistent with natural convection being the driver of the depleted zone morphology and eliminating the high resistance created by the depleted zone in 1D and 2D systems. Once the resistance of the depleted zone is negated, the high currents are hypothesized to result from enhancement of counter-ion concentration in the nanoporous gel-filled microchannel. In contrast with conventional systems, the current increases monotonically and remains stable at a high quasi-steady level in the reported systems. These results may be used to increase the efficiency and performance of future devices that utilize CP, while the ability to collect purified water with this geometry is demonstrated.
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Affiliation(s)
- Dayi Chen
- Department of Bioengineering and Department of Chemistry, University of Illinois Urbana-Champaign, 1406 W Green St, Urbana, IL 61801, USA.
| | - Jin-Tae Kim
- Department of Mechanical Science and Engineering, University of Illinois Urbana-Champaign, 1206 W. Green St., Urbana, IL 61801, USA
| | - Leonardo P Chamorro
- Department of Mechanical Science and Engineering, University of Illinois Urbana-Champaign, 1206 W. Green St., Urbana, IL 61801, USA
| | - Aaron T Timperman
- Department of Bioengineering and Department of Chemistry, University of Illinois Urbana-Champaign, 1406 W Green St, Urbana, IL 61801, USA.
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12
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Warren A, Sharma A, Zhang D, Li G, Archer LA. Structure and Dynamics of Electric-Field-Driven Convective Flows at the Interface between Liquid Electrolytes and Ion-Selective Membranes. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2021; 37:5895-5901. [PMID: 33961746 DOI: 10.1021/acs.langmuir.1c00374] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
At voltages above a certain critical value, Vc ≈ 20 kT/e, a space charge layer forms near ion-selective interfaces in liquid electrolytes. Interactions between the space charge and an imposed electric field drives a hydrodynamic instability known as electroconvection. Through particle tracking velocimetry we experimentally study the structure and dynamics of the resultant electroconvective flow. Consistent with previous numerical simulations, we report that, following imposition of a sufficiently large voltage, electroconvection develops gradually as pairs of counter-rotating vortices, which nucleate at the interface between an ion-selective substrate and a liquid electrolyte. Depending on the imposed voltage and cell geometry, the vorticies grow to length scales of hundreds of micrometers. Electroconvective flows are also reported to be structured and multiscale, with the size ratio of the largest to the smallest observable vortices inversely proportional to the Debye screening length.
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Affiliation(s)
- Alexander Warren
- School of Chemical and Biomolecular Engineering, Cornell University, Ithaca, New York 14853, United States
| | - Arpita Sharma
- School of Chemical and Biomolecular Engineering, Cornell University, Ithaca, New York 14853, United States
| | - Duhan Zhang
- School of Mechanical and Aerospace Engineering, Cornell University, Ithaca, New York 14853, United States
| | - Gaojin Li
- School of Chemical and Biomolecular Engineering, Cornell University, Ithaca, New York 14853, United States
| | - Lynden A Archer
- School of Chemical and Biomolecular Engineering, Cornell University, Ithaca, New York 14853, United States
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13
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Zhiyue M, Xichen Y, Li R, Yang Y, Huicheng F, Peng S. Recent advances in paper-based preconcentrators by utilizing ion concentration polarization. Electrophoresis 2021; 42:1340-1351. [PMID: 33768593 DOI: 10.1002/elps.202000291] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2020] [Revised: 02/26/2021] [Accepted: 03/15/2021] [Indexed: 11/09/2022]
Abstract
One of the most cited limitations of biochemical detection is its poor sensitivity, owing to the relatively high complexity of micro-samples. Moreover, some samples cannot be easily self-replicated and their abundance cannot be increased through traditional technologies. Therefore, the preconcentration of low-abundance samples is a key requirement for microfluidic biological analysis. In recent years, the ion-concentration polarization phenomenon has aroused widespread interest in the application of microfluidic technology. In addition, paper-based materials are readily available, easy to modify, and exhibit good hydrophilicity. The study of the ion-concentration polarization preconcentration of micro-samples in paper-based microfluidic chips is of considerable significance. In this review, we discuss the development and applications of ion-concentration polarization paper-based preconcentrator in the past 5 years, with emphasis on key progresses in chip fabrication and performance optimization under different conditions. The current needs and development prospects in this field have also been discussed.
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Affiliation(s)
- Meng Zhiyue
- School of Life Sciences, Northwestern Polytechnical University, Xi'an, P. R. China.,Key Laboratory for Space Bioscience and Biotechnology, Institute of Special Environment Biophysics, Northwestern Polytechnical University, Xi'an, P. R. China
| | - Yuan Xichen
- School of Life Sciences, Northwestern Polytechnical University, Xi'an, P. R. China.,Research and Development Institute of Northwestern Polytechnical University in Shenzhen, Shenzhen, P. R. China.,Key Laboratory for Space Bioscience and Biotechnology, Institute of Special Environment Biophysics, Northwestern Polytechnical University, Xi'an, P. R. China.,Yangtze River Delta Research Institute of Northwestern Polytechnical University, Taicang, P. R. China
| | - Ren Li
- School of Life Sciences, Northwestern Polytechnical University, Xi'an, P. R. China.,Research and Development Institute of Northwestern Polytechnical University in Shenzhen, Shenzhen, P. R. China.,Key Laboratory for Space Bioscience and Biotechnology, Institute of Special Environment Biophysics, Northwestern Polytechnical University, Xi'an, P. R. China
| | - Yang Yang
- Ministry of Education Key Laboratory of Low-grade Energy Utilization Technologies and Systems, Chongqing University, Chongqing, P. R. China
| | - Feng Huicheng
- Unmanned System Research Institute, Northwestern Polytechnical University, Xi'an, P. R. China.,MOE Key Laboratory of Micro and Nano Systems for Aerospace, Northwestern Polytechnical University, Xi'an, P. R. China
| | - Shang Peng
- School of Life Sciences, Northwestern Polytechnical University, Xi'an, P. R. China.,Research and Development Institute of Northwestern Polytechnical University in Shenzhen, Shenzhen, P. R. China.,Key Laboratory for Space Bioscience and Biotechnology, Institute of Special Environment Biophysics, Northwestern Polytechnical University, Xi'an, P. R. China
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14
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Titorova V, Mareev S, Gorobchenko A, Gil V, Nikonenko V, Sabbatovskii K, Pismenskaya N. Effect of current-induced coion transfer on the shape of chronopotentiograms of cation-exchange membranes. J Memb Sci 2021. [DOI: 10.1016/j.memsci.2020.119036] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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15
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Zheng J, Archer LA. Controlling electrochemical growth of metallic zinc electrodes: Toward affordable rechargeable energy storage systems. SCIENCE ADVANCES 2021; 7:eabe0219. [PMID: 33523975 PMCID: PMC7787491 DOI: 10.1126/sciadv.abe0219] [Citation(s) in RCA: 98] [Impact Index Per Article: 32.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2020] [Accepted: 11/12/2020] [Indexed: 05/19/2023]
Abstract
Scalable approaches for precisely manipulating the growth of crystals are of broad-based science and technological interest. New research interests have reemerged in a subgroup of these phenomena-electrochemical growth of metals in battery anodes. In this Review, the geometry of the building blocks and their mode of assembly are defined as key descriptors to categorize deposition morphologies. To control Zn electrodeposit morphology, we consider fundamental electrokinetic principles and the associated critical issues. It is found that the solid-electrolyte interphase (SEI) formed on Zn has a similarly strong influence as for alkali metals at low current regimes, characterized by a moss-like morphology. Another key conclusion is that the unique crystal structure of Zn, featuring high anisotropy facets resulting from the hexagonal close-packed lattice with a c/a ratio of 1.85, imposes predominant influences on its growth. In our view, precisely regulating the SEI and the crystallographic features of the Zn offers exciting opportunities that will drive transformative progress.
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Affiliation(s)
- Jingxu Zheng
- Department of Materials Science and Engineering, Cornell University, Ithaca, NY 14853, USA
| | - Lynden A Archer
- Department of Materials Science and Engineering, Cornell University, Ithaca, NY 14853, USA.
- Robert Frederick Smith School of Chemical and Biomolecular Engineering, Cornell University, Ithaca, NY 14853, USA
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16
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Gil V, Porozhnyy M, Rybalkina O, Butylskii D, Pismenskaya N. The Development of Electroconvection at the Surface of a Heterogeneous Cation-Exchange Membrane Modified with Perfluorosulfonic Acid Polymer Film Containing Titanium Oxide. MEMBRANES 2020; 10:membranes10060125. [PMID: 32560542 PMCID: PMC7344879 DOI: 10.3390/membranes10060125] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/12/2020] [Revised: 06/14/2020] [Accepted: 06/15/2020] [Indexed: 11/24/2022]
Abstract
One way to enhance mass transfer and reduce fouling in wastewater electrodialysis is stimulation of electroconvective mixing of the solution adjoining membranes by modifying their surfaces. Several samples were prepared by casting the perfluorosulfonic acid (PFSA) polymer film doped with TiO2 nanoparticles onto the surface of the heterogeneous cation-exchange membrane MK-40. It is found that changes in surface characteristics conditioned by such modification lead to an increase in the limiting current density due to the stimulation of electroconvection, which develops according to the mechanism of electroosmosis of the first kind. The greatest increase in the current compared to the pristine membrane can be obtained by modification with the film being 20 μm thick and containing 3 wt% of TiO2. The sample containing 6 wt% of TiO2 provides higher mass transfer in overlimiting current modes due to the development of nonequilibrium electroconvection. A 1.5-fold increase in the thickness of the modifying film reduces the positive effect of introducing TiO2 nanoparticles due to (1) partial shielding of the nanoparticles on the surface of the modified membrane; (2) a decrease in the tangential component of the electric force, which affects the development of electroconvection.
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17
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Cho I, Lee H, Kim SJ. Dynamic analysis of the extended space charge layer using chronopotentiometric measurements. MICRO AND NANO SYSTEMS LETTERS 2020. [DOI: 10.1186/s40486-020-00112-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
AbstractIn this paper, we experimentally verified the length (LESC) and the concentration (cESC) of the extended space charge (ESC) layer in front of the electrical double layer (EDL) using the chronopotentiometric measurement and the equivalent circuit model analysis. From the experimentation, the coupled-response of the EDL and the ESC layer was discriminated from the contribution of electro-osmotic flow (EOF). In addition, we derived the potential differences across the ESC (VESC) layer using the circuit model of the ICP layer under rigorous consideration of ESC and EDL. As a result, we obtained that VESC was linearly proportional to the square of the applied current (iapplied). Hence, LESC and cESC were quantitatively provided, where LESC is linear to the iapplied and cESC is constant regardless of iapplied. Thus, this experimentation could not only clarify an essential ICP theory but also guide in ESC-based applications.
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18
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Investigation on the Stability of Random Vortices in an Ion Concentration Polarization Layer with Imposed Normal Fluid Flow. MICROMACHINES 2020; 11:mi11050529. [PMID: 32456039 PMCID: PMC7281587 DOI: 10.3390/mi11050529] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Revised: 05/20/2020] [Accepted: 05/20/2020] [Indexed: 01/17/2023]
Abstract
While nanoscale electrokinetic studies based on ion concentration polarization has been actively researched recently, random vortices naturally occur, leading to significantly destabilize in laboratory experiments or practical applications. These random vortices agitate the fluid inside microchannels and let the sample molecules seriously leak out preventing them from being controlled. Therefore, several trials have been reported to regulate those uninvited fluctuations by fluid flow tangential to a nanoporous membrane. Indeed, the influence of normal flow should be studied since the mass transport happens in the normal direction to the membrane. Thus, in this work, the nonlinear influence of normal flow to the instability near ion-selective surface was investigated by fully-coupled direct numerical simulation using COMSOL Multiphysics. The investigation on the effect of normal flow revealed that a space charge layer plays a significant role in the onset and growth of instability. The normal flow from the reservoir into the ion-selective surface pushed the space charge layer and decreased the size of vortices. However, there existed a maximum point for the growth of instability. The squeeze of the space charge layer increased the gradient of ion concentration in the layer, which resulted in escalating the velocity of vortices. On the other hand, the normal flow from the ion-selective surface into the reservoir suppressed the instability by spreading ions in the expanding space charge layer, leading to the reduction of ion concentration delayed the onset of instability. These two different mechanisms rendered asymmetric transition of stability as a function of the Peclet number and applied voltage. Therefore, this investigation would help understand the growth of instability and control the inevitable random vortices for the inhibition of fluid-agitation and leakage.
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19
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Kang S, Kwak R. Pattern Formation of Three-Dimensional Electroconvection on a Charge Selective Surface. PHYSICAL REVIEW LETTERS 2020; 124:154502. [PMID: 32357025 DOI: 10.1103/physrevlett.124.154502] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/18/2019] [Revised: 11/04/2019] [Accepted: 03/16/2020] [Indexed: 06/11/2023]
Abstract
When a charge selective surface consumes or transports only cations or anions in the electrolyte, biased ion rejection initiates hydrodynamic instability, resulting in vortical fluid motions called electroconvection. In this Letter, we describe the first laboratory observation of three-dimensional electroconvection on a charge selective surface. Combining experiment and scaling analysis, we successfully categorized three distinct patterns of 3D electroconvection according to [(Ra_{E})/(Re^{2}Sc)] [electric Rayleigh number (Ra_{E}), Reynolds number (Re), Schmidt number (Sc)] as (i) polygonal, (ii) transverse, or (iii) longitudinal rolls. If Re increases or Ra_{E} decreases, pure longitudinal rolls are presented. On the other hand, transverse rolls are formed between longitudinal rolls, and two rolls are transformed as polygonal one at higher Ra_{E} or lower Re. In this pattern selection scenario, Sc determines the critical electric Rayleigh number (Ra_{E}^{*}) for the onset of each roll, resulting in Ra_{E}^{*}∼Re^{2}Sc. We also verify that convective ion flux by electroconvection (represented by an electric Nusselt number Nu_{E}) is fitted to a power law, Nu_{E}∼[(Ra_{E}-Ra_{E}^{*})/(Re^{2}Sc)]^{α_{1}}Re^{α_{2}}Pe^{α_{3}} [Péclet number (Pe)], where each term represents the characteristics of electroconvection, shear flow, and ion transport.
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Affiliation(s)
- Soohyeon Kang
- 1Department of Mechanical Engineering, Hanyang University, Seoul 04763, Republic of Korea
| | - Rhokyun Kwak
- 1Department of Mechanical Engineering, Hanyang University, Seoul 04763, Republic of Korea
- 2Institute of Nano Science and Technology, Hanyang University, Seoul 04763, Republic of Korea
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Abstract
Electrokinetic separation techniques in microfluidics are a powerful analytical chemistry tool, although an inherent limitation of microfluidics is their low sample throughput. In this article we report a free-flow variant of an electrokinetic focusing method, namely ion concentration polarization focusing (ICPF). The analytes flow continuously through the system via pressure driven flow while they separate and concentrate perpendicularly to the flow by ICPF. We demonstrate free flow ion concentration polarization focusing (FF-ICPF) in two operating modes, namely peak and plateau modes. Additionally, we showed the separation resolution could be improved by the use of an electrophoretic spacer. We report a concentration factor of 10 in human blood plasma in continuous flow at a flow rate of 15 μL min-1.
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Affiliation(s)
- Vasileios A Papadimitriou
- BIOS Lab on a Chip group, MESA+ Institute for Nanotechnology, Max Planck Centre for Complex Fluid Dynamics and Technical Medical Centre, University of Twente, Enschede 7500 AE, The Netherlands
| | - Loes I Segerink
- BIOS Lab on a Chip group, MESA+ Institute for Nanotechnology, Max Planck Centre for Complex Fluid Dynamics and Technical Medical Centre, University of Twente, Enschede 7500 AE, The Netherlands
| | - Jan C T Eijkel
- BIOS Lab on a Chip group, MESA+ Institute for Nanotechnology, Max Planck Centre for Complex Fluid Dynamics and Technical Medical Centre, University of Twente, Enschede 7500 AE, The Netherlands
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A Study of Ralex Membrane Morphology by SEM. MEMBRANES 2019; 9:membranes9120169. [PMID: 31817738 PMCID: PMC6950762 DOI: 10.3390/membranes9120169] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/03/2019] [Revised: 11/29/2019] [Accepted: 12/04/2019] [Indexed: 11/17/2022]
Abstract
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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Kovář P, Tichý D, Slouka Z. Effect of channel geometry on ion-concentration polarization-based preconcentration and desalination. BIOMICROFLUIDICS 2019; 13:064102. [PMID: 31700561 PMCID: PMC6824913 DOI: 10.1063/1.5124787] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/19/2019] [Accepted: 10/11/2019] [Indexed: 06/10/2023]
Abstract
Polarization of the ion-selective systems results in the formation of ion-depleted and ion-concentrated zones in the electrolyte layers adjacent to the system. One can employ ion-concentration polarization for the removal of charged large molecules and small ions from the flowing liquid. Removal of large molecules from the flowing solution and their local accumulation is often referred to as preconcentration, removal of small ions as desalination. Here, we study the effect of the channel geometry on the removal of charged species from their water solutions experimentally. Straight, converging, and diverging channels equipped with a pair of heterogeneous cation-exchange membranes are compared in terms of their effect on preconcentration of an observable fluorescein dye and on desalination of water solution of potassium chloride. Our results show that preconcentration of the dye is not significantly affected by the channel geometry. The distance of the preconcentration band from one of the membranes was approximately the same in all tested channel geometries. The major difference was in the location of the band within the channel, when the conical channels localized the band at one of the channel walls. The straight channel showed a slightly broader range of applicable flow rates. The semibatch desalination of 0.01M KCl solution turned out to be more efficient in conical channels, which was associated with a larger volume of the channel available for the accumulation of the concentrated solution. Our results suggest that conical channels can be advantageously used in transforming the ion-concentration-polarization-based semibatch desalination into a fully continuous one.
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Affiliation(s)
- Petr Kovář
- Department of Chemical Engineering, University of Chemistry and Technology Prague, Technická 3, Prague 6 16628, Czech Republic
| | - David Tichý
- Department of Chemical Engineering, University of Chemistry and Technology Prague, Technická 3, Prague 6 16628, Czech Republic
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Atlas I, Suss M. Theory of simultaneous desalination and electricity generation via an electrodialysis cell driven by spontaneous redox reactions. Electrochim Acta 2019. [DOI: 10.1016/j.electacta.2019.06.014] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Papadimitriou VA, Segerink LI, Eijkel JCT. Continuous focusing, fractionation and extraction of anionic analytes in a microfluidic chip. LAB ON A CHIP 2019; 19:3238-3248. [PMID: 31475716 DOI: 10.1039/c9lc00434c] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Electrokinetic focusing and separation methods, specifically ion concentration polarization focusing (ICPF), provide a very powerful and easy to use analytical tool for several scientific fields. Nevertheless, the concentrated and separated analytes are effectively trapped inside the chip in picoliter volumes. In this article we propose an ICPF device that allows continuous and selective extraction of the focused analytes. A theoretical background is presented to understand the dynamics of the system and a 1D model was developed that describes the general behavior of the system. We demonstrate the selective extraction of three fluorescent model anionic analytes and we report selective extraction of the analytes at a 300-fold increased concentration.
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Affiliation(s)
- Vasileios A Papadimitriou
- BIOS Lab on a Chip group, MESA+ Institute for Nanotechnology, Max Planck Centre for Complex Fluid Dynamics and Technical Medical Centre, University of Twente, The Netherlands.
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Warren A, Zhang D, Choudhury S, Archer LA. Electrokinetics in Viscoelastic Liquid Electrolytes above the Diffusion Limit. Macromolecules 2019. [DOI: 10.1021/acs.macromol.9b00536] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Electro-Kinetic Instability in a Laminar Boundary Layer Next to an Ion Exchange Membrane. Int J Mol Sci 2019; 20:ijms20102393. [PMID: 31091791 PMCID: PMC6566642 DOI: 10.3390/ijms20102393] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2019] [Revised: 04/17/2019] [Accepted: 04/28/2019] [Indexed: 02/03/2023] Open
Abstract
The electro-kinetic instability in a pressure driven shear flow near an ion exchange membrane is considered. The electrochemical system, through which an electrical potential drop is applied, consists in a polarization layer in contact with the membrane and a bulk. The numerical investigation contained two aspects: analysis of the instability modes and description of the Lagrangian transport of fluid and ions. Regarding the first aspect, the modes were analyzed as a function of the potential drop. The analysis revealed how the spatial distribution of forces controls the dynamics of vortex association and dissociation. In particular, the birth of a counter-clockwise vortex between two clockwise vortices, and the initiation of clusters constituting one or two envelopes wrapping a vortex group, were examined. In regards to the second aspect, the trajectories were computed with the fourth order Runge Kutta scheme for the time integration and with the biquadratric upstream scheme for the spatial and time interpolation of the fluid velocity and the ion flux. The results for the periodic mode showed two kinds of trajectories: the trochoidal motion and the longitudinal one coupled with a periodic transverse motion. For the aperiodic modes, other mechanisms appeared, such as ejection from the mixing layer, trapping by a growing vortex or merging vortices. The analysis of the local velocity field, the vortices’ shape, the spatial distribution of the forces and the ion flux components explained these trajectories.
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2D Mathematical Modelling of Overlimiting Transfer Enhanced by Electroconvection in Flow-Through Electrodialysis Membrane Cells in Galvanodynamic Mode. MEMBRANES 2019; 9:membranes9030039. [PMID: 30862024 PMCID: PMC6468424 DOI: 10.3390/membranes9030039] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/20/2019] [Revised: 03/05/2019] [Accepted: 03/06/2019] [Indexed: 11/17/2022]
Abstract
Flow-through electrodialysis membrane cells are widely used in water purification and the processing of agricultural products (milk, wine, etc.). In the research and operating practice of such systems, a significant place is occupied by a galvanodynamic (or galvanostatic) mode. 2D mathematical modelling of ion transfer in the galvanodynamic mode requires solving the problem of setting the average current density equal to a certain value, while the current density distribution in the system is uneven. This article develops a 2D mathematical model of the overlimiting transfer enhanced by electroconvection in a flow-through electrodialysis cell in the galvanodynamic mode. The model is based on the system of Navier–Stokes, Nernst–Planck, Poisson equations and equations for the electric current stream function. To set the electric mode we use a boundary condition, relating the electric field strength and current density. This approach allows us to describe the formation of the extended space charge region and development of electroconvection at overlimiting currents. For the first time, chronopotentiograms and current–voltage characteristics of the membrane systems are calculated for the galvanodynamic mode taking into account the forced flow and development of electroconvection. The behaviors of the calculated chronopotentiograms and current–voltage characteristic coincide qualitatively with experimental data. The effects of the electrolyte concentration, forced flow velocity and channel size on the mass transfer at overlimiting currents are estimated.
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Kim J, Davidson S, Mani A. Characterization of Chaotic Electroconvection near Flat Inert Electrodes under Oscillatory Voltages. MICROMACHINES 2019; 10:mi10030161. [PMID: 30813604 PMCID: PMC6470596 DOI: 10.3390/mi10030161] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/01/2019] [Revised: 02/20/2019] [Accepted: 02/20/2019] [Indexed: 11/16/2022]
Abstract
The onset of electroconvective instability in an aqueous binary electrolyte under external oscillatory electric fields at a single constant frequency is investigated in a 2D parallel flat electrode setup. Direct numerical simulations (DNS) of the Poisson–Nernst–Planck equations coupled with the Navier–Stokes equations at a low Reynolds number are carried out. Previous studies show that direct current (DC) electric field can create electroconvection near ion-selecting membranes in microfluidic devices. In this study, we show that electroconvection can be generated near flat inert electrodes when the applied electric field is oscillatory in time. A range of applied voltage, the oscillation frequency and the ratio of ionic diffusivities is examined to characterize the regime in which electroconvection takes place. Similar to electroconvection under DC voltages, AC electroconvection occurs at sufficiently high applied voltages in units of thermal volts and is characterized by transverse instabilities, physically manifested by an array of counter-rotating vortices near the electrode surfaces. The oscillating external electric field periodically generate and destroy such unsteady vortical structures. As the oscillation frequency is reduced to O(10−1) of the intrinsic resistor–capacitor (RC) frequency of electrolyte, electroconvective instability is considerably amplified. This is accompanied by severe depletion of ionic species outside the thin electric double layer and by vigorous convective transport involving a wide range of scales including those comparable to the distance L between the parallel electrodes. The underlying mechanisms are distinctly nonlinear and multi-dimensional. However, at higher frequencies of order of the RC frequency, the electrolyte response becomes linear, and the present DNS prediction closely resembles those explained by 1D asymptotic studies. Electroconvective instability supports increased electric current across the system. Increasing anion diffusivity results in stronger amplification of electroconvection over all oscillation frequencies examined in this study. Such asymmetry in ionic diffusivity, however, does not yield consistent changes in statistics and energy spectrum at all wall-normal locations and frequencies, implying more complex dynamics and different scaling for electrolytes with unequal diffusivities. Electric current is substantially amplified beyond the ohmic current at high oscillation frequencies. Also, it is found that anion diffusivity higher than cation has stronger impact on smaller-scale motions (≲0.1L).
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Affiliation(s)
- Jeonglae Kim
- School for Engineering of Matter, Transport and Energy, Arizona State University, Tempe, AZ 85287, USA.
- Center for Turbulence Research, Stanford University, Stanford, CA 94305, USA.
| | - Scott Davidson
- Center for Turbulence Research, Stanford University, Stanford, CA 94305, USA.
| | - Ali Mani
- Center for Turbulence Research, Stanford University, Stanford, CA 94305, USA.
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Belloň T, Polezhaev P, Vobecká L, Svoboda M, Slouka Z. Experimental observation of phenomena developing on ion-exchange systems during current-voltage curve measurement. J Memb Sci 2019. [DOI: 10.1016/j.memsci.2018.11.037] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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30
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Akberova E, Vasil'eva V, Zabolotsky V, Novak L. Effect of the sulfocation-exchanger dispersity on the surface morphology, microrelief of heterogeneous membranes and development of electroconvection in intense current modes. J Memb Sci 2018. [DOI: 10.1016/j.memsci.2018.08.042] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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31
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Benneker AM, Gumuscu B, Derckx EGH, Lammertink RGH, Eijkel JCT, Wood JA. Enhanced ion transport using geometrically structured charge selective interfaces. LAB ON A CHIP 2018; 18:1652-1660. [PMID: 29770816 DOI: 10.1039/c7lc01220a] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
A microfluidic platform containing charged hydrogels is used to investigate the effect of geometry on charge transport in electrodialysis applications. The influence of heterogeneity on ion transport is determined by electrical characterization and fluorescence microscopy of three different hydrogel geometries. We found that electroosmotic transport of ions towards the hydrogel is enhanced in heterogeneous geometries, as a result of the inhomogeneous electric field in these systems. This yields higher ionic currents for equal applied potentials when compared to homogeneous geometries. The contribution of electroosmotic transport is present in all current regimes, including the Ohmic regime. We also found that the onset of the overlimiting current occurs at lower potentials due to the increased heterogeneity in hydrogel shape, owing to the non-uniform electric field distribution in these systems. Pinning of ion depletion and enrichment zones is observed in the heterogeneous hydrogel systems, due to electroosmotic flows and electrokinetic instabilities. Our platform is highly versatile for the rapid investigation of the effects of membrane topology on general electrodialysis characteristics, including the formation of ion depletion zones on the micro-scale and the onset of the overlimiting current.
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Affiliation(s)
- Anne M Benneker
- Soft Matter, Fluidics and Interfaces, MESA+ Institute for Nanotechnology, University of Twente, The Netherlands.
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32
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Mitigation of membrane scaling in electrodialysis by electroconvection enhancement, pH adjustment and pulsed electric field application. J Memb Sci 2018. [DOI: 10.1016/j.memsci.2017.12.005] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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33
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de Valença J, Jõgi M, Wagterveld RM, Karatay E, Wood JA, Lammertink RGH. Confined Electroconvective Vortices at Structured Ion Exchange Membranes. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2018; 34:2455-2463. [PMID: 29345950 PMCID: PMC5822219 DOI: 10.1021/acs.langmuir.7b04135] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/04/2017] [Revised: 01/17/2018] [Indexed: 05/26/2023]
Abstract
In this paper, we investigate electroconvective ion transport at cation exchange membranes with different geometry square-wave structures (line undulations) experimentally and numerically. Electroconvective microvortices are induced by strong concentration polarization once a threshold potential difference is applied. The applied potential required to start and sustain electroconvection is strongly affected by the geometry of the membrane. A reduction in the resistance of approximately 50% can be obtained when the structure size is similar to the mixing layer (ML) thickness, resulting in confined vortices with less lateral motion compared to the case of flat membranes. From electrical, flow, and concentration measurements, ion migration, advection, and diffusion are quantified, respectively. Advection and migration are dominant in the vortex ML, whereas diffusion and migration are dominant in the stagnant diffusion layer. Numerical simulations, based on Poisson-Nernst-Planck and Navier-Stokes equations, show similar ion transport and flow characteristics, highlighting the importance of membrane topology on the resulting electrokinetic and electrohydrodynamic behavior.
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Affiliation(s)
- Joeri de Valença
- Soft
Matter, Fluidics and Interfaces Group, MESA Institute
of Nanotechnology, University of Twente, 7500AE Enschede, The Netherlands
- Wetsus, European
Centre of Excellence for Sustainable Water Technology, Oostergoweg 9, 8911MA Leeuwarden, The Netherlands
| | - Morten Jõgi
- Wetsus, European
Centre of Excellence for Sustainable Water Technology, Oostergoweg 9, 8911MA Leeuwarden, The Netherlands
| | - R. Martijn Wagterveld
- Wetsus, European
Centre of Excellence for Sustainable Water Technology, Oostergoweg 9, 8911MA Leeuwarden, The Netherlands
| | - Elif Karatay
- Department
of Mechanical Engineering, Stanford University, Stanford, California 94305, United States
| | - Jeffery A. Wood
- Soft
Matter, Fluidics and Interfaces Group, MESA Institute
of Nanotechnology, University of Twente, 7500AE Enschede, The Netherlands
| | - Rob G. H. Lammertink
- Soft
Matter, Fluidics and Interfaces Group, MESA Institute
of Nanotechnology, University of Twente, 7500AE Enschede, The Netherlands
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Kim M, Wu L, Kim B, Hung DT, Han J. Continuous and High-Throughput Electromechanical Lysis of Bacterial Pathogens Using Ion Concentration Polarization. Anal Chem 2018; 90:872-880. [PMID: 29193960 PMCID: PMC6784835 DOI: 10.1021/acs.analchem.7b03746] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Electrical lysis of mammalian cells has been a preferred method in microfluidic platforms because of its simple implementation and rapid recovery of lysates without additional reagents. However, bacterial lysis typically requires at least a 10-fold higher electric field (∼10 kV/cm), resulting in various technical difficulties. Here, we present a novel, low-field-enabled electromechanical lysis mechanism of bacterial cells using electroconvective vortices near ion selective materials. The vortex-assisted lysis only requires a field strength of ∼100 V/cm, yet it efficiently recovers proteins and nucleic acids from a variety of pathogenic bacteria and operates in a continuous and ultrahigh-throughput (>1 mL/min) manner. Therefore, we believe that the electromechanical lysis will not only facilitate microfluidic bacterial sensing and analysis but also various high-volume applications such as the energy-efficient recovery of valuable metabolites in biorefinery pharmaceutical industries and the disinfection of large-volume fluid for the water and food industries.
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Affiliation(s)
- Minseok Kim
- Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Lidan Wu
- Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Bumjoo Kim
- Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Deborah T. Hung
- Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
- Department of Molecular Biology and Center for Computational and Integrative Biology, Massachusetts General Hospital, Boston, MA 02114, USA
- Department of Microbiology and Immunology, Harvard Medical School, Boston, MA 02115, USA
| | - Jongyoon Han
- Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
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35
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Nikonenko VV, Mareev SA, Pis’menskaya ND, Uzdenova AM, Kovalenko AV, Urtenov MK, Pourcelly G. Effect of electroconvection and its use in intensifying the mass transfer in electrodialysis (Review). RUSS J ELECTROCHEM+ 2017. [DOI: 10.1134/s1023193517090099] [Citation(s) in RCA: 73] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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36
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Nebavskaya K, Sarapulova V, Sabbatovskiy K, Sobolev V, Pismenskaya N, Sistat P, Cretin M, Nikonenko V. Impact of ion exchange membrane surface charge and hydrophobicity on electroconvection at underlimiting and overlimiting currents. J Memb Sci 2017. [DOI: 10.1016/j.memsci.2016.09.038] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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37
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Yang KD, Ko WR, Lee JH, Kim SJ, Lee H, Lee MH, Nam KT. Morphology‐Directed Selective Production of Ethylene or Ethane from CO
2
on a Cu Mesopore Electrode. Angew Chem Int Ed Engl 2016. [DOI: 10.1002/ange.201610432] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Affiliation(s)
- Ki Dong Yang
- Department of Materials Science and Engineering Seoul National University 1 Gwanak-ro, Gwanak-gu Seoul 08826 Korea
| | - Woo Ri Ko
- Department of Applied Chemistry Kyung Hee University Yongin, Gyeonggi 17104 Korea
| | - Jun Ho Lee
- Department of Materials Science and Engineering Seoul National University 1 Gwanak-ro, Gwanak-gu Seoul 08826 Korea
| | - Sung Jae Kim
- Department of Electrical and Computer Engineering Big Data Institute Inter-University Semiconductor Research Center Seoul National University 1 Gwanak-ro, Gwanak-gu Seoul 08826 Korea
| | - Hyomin Lee
- Department of Electrical and Computer Engineering Institute of Advanced Machines and Design Seoul National University 1 Gwanak-ro, Gwanak-gu Seoul 08826 Korea
| | - Min Hyung Lee
- Department of Applied Chemistry Kyung Hee University Yongin, Gyeonggi 17104 Korea
| | - Ki Tae Nam
- Department of Materials Science and Engineering Seoul National University 1 Gwanak-ro, Gwanak-gu Seoul 08826 Korea
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38
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Yang KD, Ko WR, Lee JH, Kim SJ, Lee H, Lee MH, Nam KT. Morphology-Directed Selective Production of Ethylene or Ethane from CO 2 on a Cu Mesopore Electrode. Angew Chem Int Ed Engl 2016; 56:796-800. [PMID: 28000371 DOI: 10.1002/anie.201610432] [Citation(s) in RCA: 147] [Impact Index Per Article: 18.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2016] [Revised: 11/15/2016] [Indexed: 11/07/2022]
Abstract
The electrocatalytic conversion of CO2 to value-added hydrocarbons is receiving significant attention as a promising way to close the broken carbon-cycle. While most metal catalysts produce C1 species, such as carbon monoxide and formate, the production of various hydrocarbons and alcohols comprising more than two carbons has been achieved using copper (Cu)-based catalysts only. Methods for producing specific C2 reduction outcomes with high selectivity, however, are not available thus far. Herein, the morphological effect of a Cu mesopore electrode on the selective production of C2 products, ethylene or ethane, is presented. Cu mesopore electrodes with precisely controlled pore widths and depths were prepared by using a thermal deposition process on anodized aluminum oxide. With this simple synthesis method, we demonstrated that C2 chemical selectivity can be tuned by systematically altering the morphology. Supported by computational simulations, we proved that nanomorphology can change the local pH and, additionally, retention time of key intermediates by confining the chemicals inside the pores.
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Affiliation(s)
- Ki Dong Yang
- Department of Materials Science and Engineering, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 08826, Korea
| | - Woo Ri Ko
- Department of Applied Chemistry, Kyung Hee University, Yongin, Gyeonggi, 17104, Korea
| | - Jun Ho Lee
- Department of Materials Science and Engineering, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 08826, Korea
| | - Sung Jae Kim
- Department of Electrical and Computer Engineering, Big Data Institute, Inter-University Semiconductor Research Center, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 08826, Korea
| | - Hyomin Lee
- Department of Electrical and Computer Engineering, Institute of Advanced Machines and Design, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 08826, Korea
| | - Min Hyung Lee
- Department of Applied Chemistry, Kyung Hee University, Yongin, Gyeonggi, 17104, Korea
| | - Ki Tae Nam
- Department of Materials Science and Engineering, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 08826, Korea
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Andersen MB, Wang KM, Schiffbauer J, Mani A. Confinement effects on electroconvective instability. Electrophoresis 2016; 38:702-711. [DOI: 10.1002/elps.201600391] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2016] [Revised: 10/20/2016] [Accepted: 10/25/2016] [Indexed: 11/10/2022]
Affiliation(s)
| | - Karen M. Wang
- Department of Mechanical Engineering Stanford University Stanford CA USA
| | - Jarrod Schiffbauer
- Faculty of Mechanical Engineering Technion‐Israel Institute of Technology Technion City Israel
| | - Ali Mani
- Department of Mechanical Engineering Stanford University Stanford CA USA
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40
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Benneker AM, Wood JA, Tsai PA, Lammertink RGH. Observation and experimental investigation of confinement effects on ion transport and electrokinetic flows at the microscale. Sci Rep 2016; 6:37236. [PMID: 27853257 PMCID: PMC5112581 DOI: 10.1038/srep37236] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2016] [Accepted: 10/25/2016] [Indexed: 01/18/2023] Open
Abstract
Electrokinetic effects adjacent to charge-selective interfaces (CSI) have been experimentally investigated in microfluidic platforms in order to gain understanding on underlying phenomena of ion transport at elevated applied voltages. We experimentally investigate the influence of geometry and multiple array densities of the CSI on concentration and flow profiles in a microfluidic set-up using nanochannels as the CSI. Particle tracking obtained under chronoamperometric measurements show the development of vortices in the microchannel adjacent to the nanochannels. We found that the direction of the electric field and the potential drop inside the microchannel has a large influence on the ion transport through the interface, for example by inducing immediate wall electroosmotic flow. In microfluidic devices, the electric field may not be directed normal to the interface, which can result in an inefficient use of the CSI. Multiple vortices are observed adjacent to the CSI, growing in size and velocity as a function of time and dependent on their location in the microfluidic device. Local velocities inside the vortices are measured to be more than 1.5 mm/s. Vortex speed, as well as flow speed in the channel, are dependent on the geometry of the CSI and the distance from the electrode.
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Affiliation(s)
- Anne M Benneker
- Soft matter, Fluidics and Interfaces Group, Faculty of Science and Technology, University of Twente, 7500 AE Enschede, The Netherlands
| | - Jeffery A Wood
- Soft matter, Fluidics and Interfaces Group, Faculty of Science and Technology, University of Twente, 7500 AE Enschede, The Netherlands
| | - Peichun A Tsai
- Soft matter, Fluidics and Interfaces Group, Faculty of Science and Technology, University of Twente, 7500 AE Enschede, The Netherlands
| | - Rob G H Lammertink
- Soft matter, Fluidics and Interfaces Group, Faculty of Science and Technology, University of Twente, 7500 AE Enschede, The Netherlands
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Nikonenko VV, Vasil'eva VI, Akberova EM, Uzdenova AM, Urtenov MK, Kovalenko AV, Pismenskaya NP, Mareev SA, Pourcelly G. Competition between diffusion and electroconvection at an ion-selective surface in intensive current regimes. Adv Colloid Interface Sci 2016; 235:233-246. [PMID: 27457287 DOI: 10.1016/j.cis.2016.06.014] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2016] [Revised: 06/09/2016] [Accepted: 06/29/2016] [Indexed: 11/19/2022]
Abstract
Considering diffusion near a solid surface and simplifying the shape of concentration profile in diffusion-dominated layer allowed Nernst and Brunner to propose their famous equation for calculating the solute diffusion flux. Intensive (overlimiting) currents generate electroconvection (EC), which is a recently discovered interfacial phenomenon produced by the action of an external electric field on the electric space charge formed near an ion-selective interface. EC microscale vortices effectively mix the depleted solution layer that allows the reduction of diffusion transport limitations. Enhancement of ion transport by EC is important in membrane separation, nano-microfluidics, analytical chemistry, electrode kinetics and some other fields. This paper presents a review of the actual understanding of the transport mechanisms in intensive current regimes, where the role of diffusion declines in the profit of EC. We analyse recent publications devoted to explore the properties of different zones of the diffusion layer. Visualization of concentration profile and fluid current lines are considered as well as mathematical modelling of the overlimiting transfer.
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Affiliation(s)
- V V Nikonenko
- Department of Physical Chemistry, Kuban State University, 149 Stavropolskaya St., 350040 Krasnodar, Russia.
| | - V I Vasil'eva
- Department of Analytical Chemistry, Voronezh State University, 394018, Universitetskaya pl. 1, Voronezh, Russia
| | - E M Akberova
- Department of Analytical Chemistry, Voronezh State University, 394018, Universitetskaya pl. 1, Voronezh, Russia
| | - A M Uzdenova
- Department of Computer Technology and Applied Mathematics, Kuban State University, 149 Stavropolskaya St., 350040 Krasnodar, Russia
| | - M K Urtenov
- Department of Computer Technology and Applied Mathematics, Kuban State University, 149 Stavropolskaya St., 350040 Krasnodar, Russia
| | - A V Kovalenko
- Department of Computer Technology and Applied Mathematics, Kuban State University, 149 Stavropolskaya St., 350040 Krasnodar, Russia
| | - N P Pismenskaya
- Department of Physical Chemistry, Kuban State University, 149 Stavropolskaya St., 350040 Krasnodar, Russia
| | - S A Mareev
- Department of Physical Chemistry, Kuban State University, 149 Stavropolskaya St., 350040 Krasnodar, Russia
| | - G Pourcelly
- Institut Européen des Membranes, UMR 5635, Université Montpellier, ENSCM, CNRS, CC047, 34095 Montpellier Cedex 5, France
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42
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Tedesco M, Hamelers H, Biesheuvel P. Nernst-Planck transport theory for (reverse) electrodialysis: I. Effect of co-ion transport through the membranes. J Memb Sci 2016. [DOI: 10.1016/j.memsci.2016.03.012] [Citation(s) in RCA: 138] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Karatay E, Andersen MB, Wessling M, Mani A. Coupling between Buoyancy Forces and Electroconvective Instability near Ion-Selective Surfaces. PHYSICAL REVIEW LETTERS 2016; 116:194501. [PMID: 27232024 DOI: 10.1103/physrevlett.116.194501] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/16/2015] [Indexed: 06/05/2023]
Abstract
Recent investigations have revealed that ion transport from aqueous electrolytes to ion-selective surfaces is subject to electroconvective instability that stems from coupling of hydrodynamics with electrostatic forces. These systems inherently involve fluid density variation set by salinity gradients. However, the coupling between the buoyancy effects and electroconvective instability has not yet been investigated although a wide range of electrochemical systems are naturally prone to these interplaying effects. In this study we thoroughly examine the interplay of gravitational convection and chaotic electroconvection. Our results reveal that buoyant forces can significantly influence the transport rates, otherwise set by electroconvection, when the Rayleigh number Ra of the system exceeds a value Ra∼1000. We show that buoyancy forces can significantly alter the flow patterns in these systems. When the buoyancy acts in the stabilizing direction, it limits the extent of penetration of electroconvection, but without eliminating it. When the buoyancy destabilizes the flow, it alters the electroconvective patterns by introducing upward and downward fingers of respectively light and heavy fluids.
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Affiliation(s)
- Elif Karatay
- Department of Mechanical Engineering, Stanford University and Center for Turbulence Research, Stanford University, Stanford, California 94305, USA
| | - Mathias Bækbo Andersen
- Department of Mechanical Engineering, Stanford University and Center for Turbulence Research, Stanford University, Stanford, California 94305, USA
| | - Matthias Wessling
- RWTH Aachen University, Aachener Verfahrenstechnik, 52056 Aachen, Germany
| | - Ali Mani
- Department of Mechanical Engineering, Stanford University and Center for Turbulence Research, Stanford University, Stanford, California 94305, USA
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44
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On the Dynamical Regimes of Pattern-Accelerated Electroconvection. Sci Rep 2016; 6:22505. [PMID: 26935925 PMCID: PMC4776150 DOI: 10.1038/srep22505] [Citation(s) in RCA: 78] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2015] [Accepted: 02/15/2016] [Indexed: 11/21/2022] Open
Abstract
Recent research has established that electroconvection can enhance ion transport at polarized surfaces such as membranes and electrodes where it would otherwise be limited by diffusion. The onset of such overlimiting transport can be influenced by the surface topology of the ion selective membranes as well as inhomogeneities in their electrochemical properties. However, there is little knowledge regarding the mechanisms through which these surface variations promote transport. We use high-resolution direct numerical simulations to develop a comprehensive analysis of electroconvective flows generated by geometric patterns of impermeable stripes and investigate their potential to regularize electrokinetic instabilities. Counterintuitively, we find that reducing the permeable area of an ion exchange membrane, with appropriate patterning, increases the overall ion transport rate by up to 80%. In addition, we present analysis of nonpatterned membranes, and find a novel regime of electroconvection where a multivalued current is possible due to the coexistence of multiple convective states.
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