Electro-osmotic instability of concentration enrichment in curved geometries for an aqueous electrolyte
Name
PhysRevFluids.5.091701.pdf
Description
Published version
Size
867.17 KB
Format
Adobe PDF
Checksum (MD5)
dc8d1eaf57896d88b4ef1f99c0088267
Author(s)
Xu, Bingrui
Gu, Zhibo
Liu, Wei
Huo, Peng
Zhou, Yueting
Rubinstein, SM
Bazant, MZ
Zaltzman, B
Rubinstein, I
Deng, Daosheng
Date Issued
2020
Journal
Physical Review Fluids
Publisher
American Physical Society (APS)
Version
Final published version
Abstract
© 2020 American Physical Society. We report that an electro-osmotic instability of concentration enrichment in curved geometries for an aqueous electrolyte, as opposed to the well-known one, is initiated exclusively at the enriched interface (anode), rather than at the depleted one (cathode). For this instability, the limitation of an unrealistically high material Peclet number in planar geometry is eliminated by the strong electric field arising from the line charge singularity. In a model setup of concentric circular electrodes, we show by stability analysis, numerical simulation, and experimental visualization that instability occurs at the inner anode, below a critical radius of curvature. The stability criterion is also formulated in terms of a critical electric field and extended to arbitrary (two-dimensional) geometries by conformal mapping. This discovery suggests that transport may be enhanced in processes limited by salt enrichment, such as reverse osmosis, by triggering this instability with needlelike electrodes.
MIT Department
Massachusetts Institute of Technology. Department of Chemical Engineering
Massachusetts Institute of Technology. Department of Mathematics
Terms of Use
Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use.
Persistent DSpace Link
DOI of Published Version
https://doi.org/10.1103/PHYSREVFLUIDS.5.091701
