https://doi.org/10.15255/KUI.2001.017
Published: Kem. Ind. 51 (5) (2002) 205–212
Paper reference number: KUI-17/2001
Paper type: Original scientific paper

A Square-wave Voltammetry of Reversible Redox Reaction on Thin Mercury Film Covered Solid Electrode

M. Lovrić

Abstract

A mathematical model of reversible redox reaction of an amalgam forming metal ion, measured by both direct and an anodic stripping square-wave voltammetry, on a thin mercury film covered solid stationary disk electrode is developed. ASSWV was simulated by considering that the anodic stripping scan was preceded by a short period of an amalgam accumulation. Distributions of the metal atoms concentrations in the film are calculated for both the direct SWV and ASSWV. Dependence of the direct SWV and ASSWV net peak currents (фP,net) on the logarithm of dimensionless film thickness (γ) is analysed. It is shown that in the direct SWV, the well known maximum of the фP,net net versus log γ relationship vanishes if the pulse amplitude nEsw is diminished below ±30 mV. The maximum appears when γ is approximatelly equal to the diffusion layer thickness of metal atoms in the film. It is also demonstrated that ASSWV фP,net decreases sigmoidally with the increasing of log γ. This is contrary to the predictions of the models in which the accumulation period was neglected.

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Keywords

square-wave voltammetry, thin-layer mercury electrode, amalgam accumulation