Irreversible binding of mercury from contaminated soil

Abstract

The 1,3-benzenediamidoethanethiol dianion (BDET 2−) has been designed and synthesized to immobilize mercury from contaminated soils. In this study, mercury contaminated soil samples from the Appalachia Region of Eastern Kentucky were collected and tested with the sodium salt of this ligand. Multiple binding sites on the BDET 2− ligand have led to stable mercury–ligand precipitates that are capable of withstanding adverse oxidative and pH conditions. Results indicated that 99.6% of the mercury in the soil samples could be immobilized from an average starting concentration of 10.3 mg of mercury per gram of soil (mg Hg/g soil). The precipitates were tested for stability through leaching and oxidative-digestion tests, and yielded leaching rates less than 5×10 −11 g/ml at times 2, 30 and 60 days at a pH range of 0.0–10.0.