Kinetics of reductive dissolution of sodium bismuthate by CeIII and MnII ions

Abstract

The kinetics of reductive dissolution of NaBio₃ by Mn^II and Ce^III ions are studied as a function of [Mn^II] or [Ce^III][Bi^III], [H⁺] and temperature. They fit a simple inverse-cubic rate law and can be readily interpreted using a mechanism in which the rate-determining step is the reaction between an adsorbed reducing species (i.e. a Mn^II or Ce^III ion) and its associated surface site; protonation of the surface site promotes the rate of reaction. The rate of dissolution decreases with increasing initial concentration of Bi^III ions owing to competitive inhibition by the latter species. A kinetic model, based on this mechanism, is applied and provides a quantitative description of the observed kinetics.