Publications [#57947] of Heileen Hsu-Kim

Papers Published

1. Hsu-Kim, Heileen and Sedlak, David L., Similarities between inorganic sulfide and the strong Hg(II)-complexing ligands in municipal wastewater effluent, Environmental Science and Technology, vol. 39 no. 11 (2005), pp. 4035 - 4041 [es050013i]
   (last updated on 2007/04/09)

   Abstract:
   Municipal wastewater effluent contains ligands that form Hg(II) complexes that are inert in the presence of glutathione (GSH) during competitive ligand exchange experiments. In this study, the strong ligands in wastewater effluent were further characterized by comparing their behavior with sulfide-containing ligands in model solutions and by measuring their concentration after exposing them to oxidants. The strong Hg(II) complexes in wastewater effluent and the complexes formed when Hg(II) was added to S(-II) were retained during C ₁₈ solid-phase extraction (SPE) and did not dissociate in the presence of up to 100 μM GSH. In contrast, Hg(II) complexes with dissolved humic acid were hydrophilic and dissociated in the presence of GSH. The combination of sulfide and humic acid resulted in formation of Hg(II) complexes that were inert to GSH and were only partially retained by C₁₈-SPE, indicating that NOM interacted with the Hg-sulfide complexes. When wastewater effluent samples and model solutions of free sulfide, Zn-sulfide, and Fe-sulfide were exposed to 0.14 mM NaOCI for 1 h (to mimic conditions encountered during chlorine disinfection), the strong Hg(II)-complexing ligands were completely removed. Exposure of the wastewater effluent and the model ligands to oxygen for 2 weeks resulted in approximately 60% to 75% loss of strong ligands. The strong ligands that remained in the oxygen-oxidized samples were resistant to further oxidation by chlorine, indicating that oxidation of S(-II) results in the formation of other sulfur-containing ligands such as SB that form strong complexes with Hg(II). © 2005 American Chemical Society.

   Keywords:
   Wastewater;Sulfur compounds;Mercury (metal);Complexation;Extraction;Zinc sulfide;Organic acids;Oxidation;Chlorine;