Kinetics of the Oxidative Degradation of KU-2×8 Cation-Exchange Resin Using Hydrogen Peroxide

Abstract

Kinetics of the oxidative degradation of universal strongly acidic cation-exchange resin KU-2×8 is studied using hydrogen peroxide. The effect the nature and concentration of catalytic additives in the form of copper(II) and iron(II) salts have on the oxidation process is determined. It is found that in noncatalytic degradation, the effective rate constant rises from 0.24 × 10−3 to 7.54 × 10−3 g1/3 min−1 upon an increase in temperature in the range of 348–368 K. The activation energies of the noncatalytic oxidation of the cation-exchange resin with hydrogen peroxide are characteristic of a process that occurs in the kinetic region and total 132.46–141.96 kJ/mol. It is shown that introducing catalytic additives helps lower Ea of the process to 40.90 kJ/mol and the temperature of degradation by 15–25 K. The pattern of change in the surface morphology of the cation-exchange resin granules during oxidative decomposition is revealed. The approximate composition of the products of cation-exchange resin decomposition is identified via gas chromatography–mass spectrometry.