title: Competition between diffusion and electroconvection at an ion-selective surface in intensive current regimes.
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.
authors.affiliation: Department of Physical Chemistry, Kuban State University, 149 Stavropolskaya St., 350040 Krasnodar, Russia. Electronic address: v_nikonenko@mail.ru.
authors.forename: V V
authors.initials: VV
authors.lastname: Nikonenko
authors.affiliation: Department of Analytical Chemistry, Voronezh State University, 394018, Universitetskaya pl. 1, Voronezh, Russia.
authors.forename: V I
authors.initials: VI
authors.lastname: Vasil'eva
authors.affiliation: Department of Analytical Chemistry, Voronezh State University, 394018, Universitetskaya pl. 1, Voronezh, Russia.
authors.forename: E M
authors.initials: EM
authors.lastname: Akberova
authors.affiliation: Department of Computer Technology and Applied Mathematics, Kuban State University, 149 Stavropolskaya St., 350040 Krasnodar, Russia.
authors.forename: A M
authors.initials: AM
authors.lastname: Uzdenova
authors.affiliation: Department of Computer Technology and Applied Mathematics, Kuban State University, 149 Stavropolskaya St., 350040 Krasnodar, Russia.
authors.forename: M K
authors.initials: MK
authors.lastname: Urtenov
authors.affiliation: Department of Computer Technology and Applied Mathematics, Kuban State University, 149 Stavropolskaya St., 350040 Krasnodar, Russia.
authors.forename: A V
authors.initials: AV
authors.lastname: Kovalenko
authors.affiliation: Department of Physical Chemistry, Kuban State University, 149 Stavropolskaya St., 350040 Krasnodar, Russia.
authors.forename: N P
authors.initials: NP
authors.lastname: Pismenskaya
authors.affiliation: Department of Physical Chemistry, Kuban State University, 149 Stavropolskaya St., 350040 Krasnodar, Russia.
authors.forename: S A
authors.initials: SA
authors.lastname: Mareev
authors.affiliation: Institut Européen des Membranes, UMR 5635, Université Montpellier, ENSCM, CNRS, CC047, 34095 Montpellier Cedex 5, France.
authors.forename: G
authors.initials: G
authors.lastname: Pourcelly
keywords: Diffusion layer; Electroconvection; Ion-selective surface; Laser interferometry; Mathematical modelling; Overlimiting current