ELECTROSTATIC CORRELATIONS AND NON-ELECTROSTATIC EFFECTS ON ION DYNAMICS IN ALTERNATING CURRENT VOLTAGES*

ELECTROSTATIC CORRELATIONS AND NON-ELECTROSTATIC EFFECTS ON ION DYNAMICS IN ALTERNATING CURRENT VOLTAGES*

ALIJÓ, P. H. R.; TAVARES, F. W.; BISCAIA JR, E. C.; SECCHI, A. R.

Artigo:

We present a modified Poisson-Nernst-Planck (mPNP) model to include both non-electrostatic effects and electrostatic correlations on ion dynamics near charged parallel blocking electrodes. The first contribution appears directly on ion chemical potential, whereas the latter is addressed by a modified Poisson equation. The model consists in a partial-differential-algebraic equation system, solved by the DASSLC code, implemented in EMSO simulator. Monte Carlo simulation results were properly described without the aid of fitting parameters. The model predicts overscreening for 2:1 electrolytes, which was not accessed by classical PNP-like approaches. Alternate voltage simulations show a meaningful effect of electrostatic correlations on mobile charge dynamics for 2:1 electrolytes, where ion-ion correlations are stronger near the electrodes. This is the first report accounting for electrostatic correlations on ion dynamics via PNP-like models under alternating current (ac) voltages to the best of our knowledge.

We present a modified Poisson-Nernst-Planck (mPNP) model to include both non-electrostatic effects and electrostatic correlations on ion dynamics near charged parallel blocking electrodes. The first contribution appears directly on ion chemical potential, whereas the latter is addressed by a modified Poisson equation. The model consists in a partial-differential-algebraic equation system, solved by the DASSLC code, implemented in EMSO simulator. Monte Carlo simulation results were properly described without the aid of fitting parameters. The model predicts overscreening for 2:1 electrolytes, which was not accessed by classical PNP-like approaches. Alternate voltage simulations show a meaningful effect of electrostatic correlations on mobile charge dynamics for 2:1 electrolytes, where ion-ion correlations are stronger near the electrodes. This is the first report accounting for electrostatic correlations on ion dynamics via PNP-like models under alternating current (ac) voltages to the best of our knowledge.

Palavras-chave:

DOI: 10.5151/chemeng-cobeq2014-1348-19727-152033

Referências bibliográficas

• [1] ALIJÓ, P. H. R.; TAVARES, F. W.; BISCAIA Jr., E. C.; SECCHI, A. R. Steric effects on ion dynamics near charged electrodes. Fluid Phase Equilib., v. 362, p. 177-186, 2014a. ALIJÓ, P. H. R.; TAVARES, F. W.; BISCAIA Jr., E. C.; SECCHI, A. R. Electrostatic correlations on ion dynamics in alternating current voltages. Langmuir, submitted, 2014b. BAZANT, M. Z.; STOREY, B. D.; KORNYSHEV, A. A. Double Layer in Ionic Liquids: Overscreening versus Crowding. Phys. Rev. Lett., v. 106, p. 046102-1-4, 2011.
• [2] STOREY, B. D.; BAZANT, M. Z. Effects of electrostatic correlations on electrokinetic phenomena. Phys. Rev. E: Stat., Nonlinear, Soft Matter Phys., v. 86, p. 056303-1-11, 2012.
• [3] BODA, D.; FAWCETT, W. R.; HENDERSON, D.; SOKOŁOWSKI, S. Monte Carlo, density functional theory, and Poisson–Boltzmann theory study of the structure of an electrolyte near an electrode. J. Chem. Phys., v. 116, p. 7170-7176, 2002.
• [4] OLESEN, L. H.; BAZANT, M. Z.; BRUUS, H. Strongly nonlinear dynamics of electrolytes in large ac voltages. Phys. Rev. E: Stat., Nonlinear, Soft Matter Phys., v. 82, p. 011501-1-29, 2010.
• [5] SECCHI, A. R. Differential-Algebraic System Solver in C - Version 3.7 (2010). Universidade Federal do Rio Grande do Sul, Brazil. http://www.enq.ufrgs.br/enqlib/numeric, last access on 29/12/2013.
• [6] SOARES, R. P.; SECCHI, A. R. EMSO: A New Environment for Modeling, Simulation and Optimization. Comput.-Aided Chem. Eng., v. 14, p. 947-952, 2003.
• [7] BIKERMAN, J. J. Structure and capacity of electrical double layer. Philos. Mag., v. 33, p. 384-397, 1942.

Como citar:

ALIJÓ, P. H. R.; TAVARES, F. W.; BISCAIA JR, E. C.; SECCHI, A. R.; "ELECTROSTATIC CORRELATIONS AND NON-ELECTROSTATIC EFFECTS ON ION DYNAMICS IN ALTERNATING CURRENT VOLTAGES*", p-15571-15578. In: Anais do XX Congresso Brasileiro de Engenharia Química - COBEQ 2014 [= Blucher Chemical Engineering Proceedings, v.1, n.2]. São Paulo: Blucher, 2015.
ISSN 23591757, DOI 10.5151/chemeng-cobeq2014-1348-19727-152033