Dynamics of the redox sorption of substances controlled by its external- and internal-diffusion transport and by the rate of its chemical transformation at two mobile boundaries

A kinetic model of redox sorption incorporating the main stages of the external- and internal-diffusion transfer of the oxidant and the rate of its chemical transformation at two mobile boundaries was used to describe the behavior of a stationary grainy bed of a sorbent in a column-type reactor. It was established how the dynamic characteristics of the bed depend on the dimensionless kinetic parameters of the sorption system. The data obtained can be used to describe the reductive sorption of oxygen by a grainy layer of an H-form EI-21 electron-ion copper-containing exchanger. An optimal method for determining kinetic constants from experimental data was proposed. Regions in which reductive sorption is limited by various diffusional stages were identified. It was examined how the contributions from external- and internal-diffusion resistances change with time during the sorption process.