Oxidation of Aqueous Dimethyl Sulfoxide (DMSO) Using UV, O3, and UV/O3

Abstract

Dimethyl sulfoxide (DMSO) is extensively used in industry and a large amount of wastewater that contains DMSO is discharged. This investigation evaluates the feasibility and effectiveness of the use of UV, O3 and UV/O3 to degrade aqueous DMSO. DMSO oxidation tests were performed with initial DMSO concentrations of 400–890 mg/L, at various ozone dosages (5.44, 8.25, 12.80 mg/L.min), solution pH values (acidic, alkaline, uncontrolled), and UV irradiation power intensities (0 and 2.25 W/L). Experimental results demonstrated that acidic conditions favored the degradation of DMSO and increased the mass of DMSO decomposition per unit mass of ozone consumption, in both the presence and the absence of UV. DMSO exhibited zero-order degradation kinetics when sufficient ozone was supplied. The cost of the ozone or UV/ozone process per unit volume of wastewater with a DMSO concentration of 2500 mg/L is comparable to that of the UV/H2O2-biological and electrolysis-biological processes described in the literature.