The products from the oxidation of H 2S in seawater
Abstract
The oxidation of sulfide in seawater is an overall second-order reaction, first-order with respect to both sulfide and oxygen. The major products formed from the oxidation of H 2S with O 2 have been measured in water and seawater as a function of pH (4-10), temperature (10-45°C), and salinity (0-36). The major products formed from the oxidation of H 2S were SO 2-3, S 2O 2-3, and SO 42-. The pH dependence of the product distribution has been attributed to the effect of pH on the rate of the individual reaction steps. A kinetic model was developed to account for the distribution of the reactants and products. The model is based on the following overall reactions: ??? Rate constants were determined for the oxidation of HS - and formation of SO 32- ( k1), for the oxidation of SO 32- and production of SO 42- ( k2) and for the formation of S 2O 32- from HS - and SO 32- ( k3). These values of k1, k2, and k3 as a function of pH, temperature, and salinity can predict the concentrations of the measured reactants and products within experimental error. The effect of metals (Fe 3+, Fe 2+, Mn 2+, Cu 2+, and Pb 2+) and oxides (α-FeOOH and MnO 2) on the product distribution has also been examined. The field measurements from the Framvaren Fjord (Norway) and Cariaco Trench (Venezuela) are in reasonable agreement with the laboratory results at the same concentration of Fe 2+ as in the anoxic basins.
- Publication:
-
Geochimica et Cosmochimica Acta
- Pub Date:
- April 1993
- DOI:
- 10.1016/0016-7037(93)90108-9
- Bibcode:
- 1993GeCoA..57.1705Z