Collect. Czech. Chem. Commun. 1998, 63, 20-30

Adsorption and Oxidation of Thiosulfate on a Platinum Electrode in Acid Solution

Tomáš Loučka

J. E. Purkyně University, Department of the Environment, 400 01 Ústí nad Labem, Czech Republic


The adsorption of thiosulfate on a platinum electrode was measured at the open circuit potential. A monolayer of the adsorption products covers the electrode at lower thiosulfate concentrations. The charge used up during the reduction of the monolayer roughly corresponds to 0.5 electron per surface site (e.p.s.), the charge used up during the oxidation of the monolayer after reduction corresponds approximately to 4 e.p.s. Multiple adsorbed layers, which are presumably constituted mainly by adsorbed sulfur, build up at higher thiosulfate concentrations. The amount of the adsorbed substance increases with increasing thiosulfate concentration and time of adsorption. Desorption from the surface coated by multiple layers can take place in supporting electrolyte solution. The build-up of multiple adsorbed sulfur layers also takes place during adsorption from solutions of colloidal sulfur.

Keywords: Electrochemistry; Multilayers of adsorbed sulfur; Colloidal sulfur; Reduction to dithionite; Oxidation to dithionate.