Modelling of Electrochemically Switchable Ion Transport in Nanoporous Membranes with Conductive Surface

Ryzhkov, Ilya I.; Vyatkin, Anton S.; Медведева, М. И.

doi:10.17516/1997-1397-2019-12-5-579-589

Cited by 6 publications

(2 citation statements)

References 33 publications

(50 reference statements)

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“…We consider the case when the injection at the cathode is proportional to the electric field strength z = 0 : q = a(t)E (E is electric field strength, and the modulation a(t) = a(1 + α sin(2πf t)) with amplitude α and frequency f is provided by oscillation of the potential on an ion-selective membrane [23] (or a grid electrode) near the cathode.…”

Section: Governing Equationsmentioning

confidence: 99%

Effect of charge modulation on the electroconvective flow of a low conducting liquid

Nekrasov

Smorodin

2021

Math. Model. Nat. Phenom.

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Nonlinear evolution of the electroconvective flow patterns is analysed in a horizontal low conductive fluid layer under heating from above and under modulated charge injection. To examine the complex evolution of the system, numerical simulations are carried out using a finite difference method. The influence of amplitude and frequency modulation on the oscillatory electroconvection is studied. Traveling waves with modulated amplitudes and phase velocities and synchronously modulated patterns are found as stable solutions.

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Section: Governing Equationsmentioning

confidence: 99%

Effect of charge modulation on the electroconvective flow of a low conducting liquid

Nekrasov

Smorodin

2021

Math. Model. Nat. Phenom.

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“…The SC model was revisited recently [19] by providing an essential simplification of working formulas, and further used to predict the ionic conductivity of carbon nanotubes [20]. The extension of SC model to the nanopores with constant surface potential was first suggested in [22] and applied to description of membrane potential at zero current in conductive nanopores [23][24][25]. It was demonstrated that the induced charge effects can essentially affect the magnitude of membrane potential.…”

Section: Introductionmentioning

confidence: 99%

Modelling the Ionic Conductivity of Nanopores with Electrically Conductive Surface

Krom

Медведева

Ryzhkov

et al. 2021

Journal of Siberian Federal University. Mathematics &Amp; Physics

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The ionic conductivity of nanopores with electrically conductive surface is investigated theoretically. The generalization of two-dimensional (2D) Space–charge model to calculating the ion transport under the applied potential gradient in a nanopore with constant surface potential is proposed for the first time. The results are compared with one-dimensional (1D) Uniform potential model, which is derived from the Space–charge model by assuming the independence of potential, ion concentrations, and pressure on the radial coordinate. We have found that the increase of surface potential magnitude leads to the enhancement of conductivity due to the increase of counter–ion concentration inside the nanopore. It is shown that the 1D and 2D models provide close results when the pore radius is smaller than the Debye length. Otherwise, the 1D model essentially overestimates the ionic conductivity. According to the 2D model, the ionic conductivity decreases with increasing the nanopore radius, while the 1D model predicts the opposite trend, which is not physically correct

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Ionic Conductivity of Nanopores with Electrically Conductive Surface: Comparison Between 1D and 2D Models

Krom

Ryzhkov

2021

Advcd Theory and Sims

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Nanoporous membranes with high ionic conductivity are advantageous in such electrochemical processes as (reverse) electrodialysis, capacitive deionization, and hydrogen energy conversion. In membranes with electrically conductive surface, the conductivity can be regulated by varying the surface potential. This work is devoted to the theoretical study of switchable ionic conductivity. The transport of ions is described by the 2D space charge model and 1D uniform potential model taking into account the Stern layer. The conductivity decreases with lowering the Stern layer permittivity due to enhanced screening of electronic surface charge. The growth of surface potential leads to the conductivity enhancement due to accumulation of more counter‐ions inside the nanopore. For nanopores with constant surface charge density, the ionic conductivity follows the bulk electrolyte conductivity at high ion concentrations, and becomes independent of concentration when the latter is low. In contrast, the nanopores with constant surface potential demonstrate a linear decrease of conductivity with lowering the logarithm of ion concentration. The deviation between 1D and 2D models becomes noticeable at higher values of Stern layer permittivity, pore radius, electrolyte concentration, and surface potential. The proposed models are verified by comparison with experimental data on pure water conductivity in charged porous matrix.

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Modelling of Electrochemically Switchable Ion Transport in Nanoporous Membranes with Conductive Surface

Cited by 6 publications

References 33 publications

Effect of charge modulation on the electroconvective flow of a low conducting liquid

Effect of charge modulation on the electroconvective flow of a low conducting liquid

Modelling the Ionic Conductivity of Nanopores with Electrically Conductive Surface

Ionic Conductivity of Nanopores with Electrically Conductive Surface: Comparison Between 1D and 2D Models

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