Nitrogen Dioxide Absorption and Sulfide Oxidation in Aqueous Sulfide.

Rates of nitrogen dioxide (NO2) absorption and sulfide oxidation were measured in a highly characterized stirred cell contactor at 55 °C, with O2 present in the gas phase. The rate constant of the reaction between NO2 and sul-fide at 55 °C was determined to be 26.4 x105 M-1sec-1. A reaction mechanism was proposed that is consistent with the kinetic data. NO2 absorption initiates sulfide oxidation in the presence of oxygen. The rate of sulfide oxidation increased with sulfide and oxygen concentration and with the rate of NO2 absorption. Furthermore, thiosulfate was an effective inhibitor of sulfide oxidation.