Photocatalytic Formation of Particulate Mercury in Sulfide and Organic Rich Water: Measurements and Implications for Industrial Wastewater Treatment

摘要

Mercury (Hg) is environmentally persistent and has long been recognized as toxic, principally in relation to its effects on humans following acute high-level or prolonged low-level exposures. Annually, anthropogenic contributions to current background levels in the aqueous environment are from industrial point sources including chlor-alkali facilities using Hg-cell technology, producing valuable chemicals such as chlorine, hydrogen, and caustic soda. In 2012, estimates that 2.8 tons of intentional and non-intentional releases into aqueous systems represent up to 5.5% of total anthropogenic Hg releases. The risk from long-range aqueous and atmospheric transport of Hg, coupled with speciation transformations that cause bioaccumulation in biota and humans have brought leading organizations such as the World Health Organization and the U.S. Environmental Protection Agency to call for more stringent standards that reduce or eliminate Hg wherever possible. As gas-phase Hg removal are becoming more apparent, challenges remain in achieving trace Hg levels in industrial process wastewater discharge.