Kinetics of oxidation of dimethyl sulfide by hydrogen peroxide in acidic and alkaline medium

The control of malodorous conditions associated with sulphide wastes from kraft pulping processes by oxidation of dimethyl sulphoxide is discussed. The kinetics and mechanisms of this oxidation in aqueous solution were investigated spectrophotometrically. The reaction was first order with respect both to hydrogen peroxide and dimethyl sulphide and catalysed by strong acids. The catalytic effect of acids was most pronounced below pH 1. Calculated activation energies for reaction solutions of pH 1, unbuffered, pH 6, and pH 7, respectively were 10.94, 10.73, 11,73 and 3.41 kcal per mol. The difference in activation energy at pH 7 was attributable to a different reaction mechanism. Hydrogen peroxide could provide an economic means for odour control of wastewaters containing sulphur dioxide, hydrogen sulphide, mercaptans and dimethyl sulphides as all the oxidation products were odourless.