Degradation of dimethyl sulfoxide through fluidized-bed Fenton process: kinetic analysis

In this study, fluidized-bed Fenton process (FBF) was used to degrade dimethyl sulfoxide (DMSO), one of the most widely used solvents. Oxidation by Fenton's reagent, Fe+2 and H2O2, is one of the cheapest advanced oxidation processes due to the high availability of the reagents. FBF is a modified approach that reduces the large amount of iron oxide sludge formed in conventional Fenton process. The optimal treatment efficiencies by FBF with 2 h of reaction were 95.22 % of DMSO degradation and 34.38 % of COD removal at the conditions of 5 mM DMSO, 68.97 g/L SiO2 carrier, pH(initial) 3.0, 5 mM Fe2+, and 32.5 mM H2O2. The kinetic study was also done to investigate the two stages involved in the oxidation. The first stage fitted the zero reaction order with overall initial rate's apparent rate constant, k(1), of -0.099. The second stage fitted the first order of DMSO degradation, with rate constant, k(2), of -0.0005.