Kinetics of reductive dissolution of sodium bismuthate by CeIII and MnII ions
Abstract
The kinetics of reductive dissolution of NaBio3 by MnII and CeIII ions are studied as a function of [MnII] or [CeIII][BiIII], [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 MnII or CeIII 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 BiIII 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.