Reaction and Mass Transfer Kinetics Model of Hydrogen Peroxide Oxidation of Starch under Influence of Ultraviolet Irradiation

Abstract

The coupled hydrogen peroxide/ultraviolet irradiation (H₂O₂/UV) process as one of environmentally friendly advanced oxidation processes (AOPs) has been successfully applied in the oxidation of corn starch. The aim of this work was to develop a simplified model for the describing of reaction kinetics and mass transfer phenomena of starch oxidation using hydrogen peroxide under influence of UV irradiation. The model development involved the elementary chemical and photochemical reactions as well as pseudo-steady state mass transfer of hydroxyl radicals from bulk liquid to the surface of starch particles. Effects of initial H₂O₂ concentration and pH were investigated. The results show that H₂O₂/UV starch oxidation follows the first order reaction with respect to H₂O₂ and starch concentrations. The proposed model satisfactorily describes the H₂O₂/UV starch oxidation phenomena, where very good agreement with experimental data was obtained. Hydroxyl radical’s mass transfer from bulk liquid to the surface of starch particles was found to be the rate controlling step for coupled H₂O₂/UV starch oxidation.