Oxidative dissolution rates of Cd and Zn in synthetic Zn-Cd sulfide solid solutions and high-Zn organic soils
We used a combination of laboratory-synthesized solid solutions of Zn-Cd sulfide and naturally Zn and Cd contaminated organic soils from a wetland to determine the potential for Cd and Zn dissolution from sulfide phases in hydric soils upon exposure to O<,2>. The kinetics of oxidative dissolution of synthetic sulfides were studied in batch reactions by monitoring dissolved S, Cd and Zn over 12 days. Dissolution of Zn, Cd and S in the organic soils was measured by subjecting intact soil columns to successive leaching events. The results showed that pure CdS is much less resistant to oxidation under fully aerated conditions than ZnS, but dissolution of Cd is strongly limited when the Zn/Cd mole ratio in the sulfide is greater than 20. The organic soil leaching experiments also showed a tendency for the relative solubility of Cd to be much lower than that of Zn. The intermittently anoxic subsoils, which have extremely high total Zn and Cd concentrations, released larger fractions of their total Zn and S upon leaching than surface soils. Leaching of Zn and S were highly correlated, suggesting that metal dissolution in this soil was a result of sulfide oxidation, whereas leached Cd was a negligible fraction of total Cd.
Cadmium organic soils oxidative dissolution solid solution sulfide zinc
M. B. McBride K. A. Barrett C. E. Martinez
Department of Crop and Soil SCiences, Cornell University, Ithaca, NY 14853. USA Department of Crop and Soil Sciences, Pennsylvania State University, University Park, PA 16802. USA
国际会议
第九届痕量元素生物地球化学国际会议(9th International Conference on the Biogeochemistry of Trace Elements)
北京
英文
641-642
2007-07-15（万方平台首次上网日期，不代表论文的发表时间）