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Updated: Aug 5, 2025

Merging Ion Concentration Polarization between Juxtaposed Ion Exchange Membranes to Block the Propagation of the Polarization Zone
Published on: February 23, 2017
Interplay between Forced Convection and Electroconvection during the Overlimiting Ion Transport through
Lorena Hernández-Pérez1, Manuel César Martí-Calatayud1, Maria Teresa Montañés1
1IEC Group, ISIRYM, Universitat Politècnica de València, Camí de Vera s/n, 46022 València, Spain.
Abstract:
Electrodialysis (ED) applications have expanded in recent years and new modes of operation are being investigated. Operation at overlimiting currents involves the phenomenon of electroconvection, which is associated with the generation of vortices. These vortices accelerate the process of solution mixing, making it possible to increase the transport of ions across the membranes. In this work, frequency analysis is applied to investigate the interaction between different parameters on the development of electroconvection near anion-exchange membranes, which would provide a basis for the development of ED systems with favored electroconvection. Chronopotentiometric curves are registered and Fast Fourier Transform analysis is carried out to study the amplitude of the transmembrane voltage oscillations. Diverse behaviors are detected as a function of the level of forced convection and current density. The synergistic combination of forced convection and overlimiting currents leads to an increase in the signal amplitude, which is especially noticeable at frequencies around 0.1 Hz. Fast Fourier Transform analysis allows identifying, for a given system, the conditions that lead to a transition between stable and chaotic electroconvection modes.
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