X-ray absorption spectroscopic evidence for the complexation of Hg(II) by reduced sulfur in soil humic substances
Abstract
Analysis of Hg(II) complexed by a soil humic acid (HA) using synchrotron-based X-ray absorption spectroscopy (XAS) revealed the importance of reduces sulfur functional groups (thiol (R-SH) and disulfide (R-SS-R)/disulfane (R-SSH)) in humic substances in the complexation of Hg(II). A two-coordinate binding environment with one oxygen atom and one sulfur atom at distances of 2.02 and 2.38 {angstrom}, respectively, was found in the first coordination shell of Hg(II) complexed by humic acid. Model calculations show that a second coordination sphere could contain one carbon atom and a second sulfur atom at 2.78 and 2.93 {angstrom}, respectively. This suggests that in addition to thiol S, disulfide/disulfane S may be involved with the complexation of Hg(II) in soil organic matter. The appearance of carbon atom in the second coordination shell suggests that one O-containing ligand such as carboxyl and phenol ligands rather than H{sub 2}O molecule is bound to the Hg(II). The involvement of oxygen ligand in addition to the reduced S ligands in the complexation of Hg(II) is due to the low density of reduced S ligands in humic substances. The XAS results from this experiment provided direct molecular level evidence for the preference of reduced S functional groups over oxygen ligandsmore »
- Authors:
-
- Kansas State Univ., Manhattan, KS (United States). Dept. of Agronomy
- Swedish Univ. of Agricultural Sciences, Umeaa (Sweden). Dept. of Forest Ecology
- Univ. of Wisconsin, Madison, WI (United States). Dept. of Soil Science
- Univ. of Minnesota, St. Paul, MN (United States). Dept. of Soil, Water, and Climate
- Publication Date:
- Sponsoring Org.:
- USDOE, Washington, DC (United States)
- OSTI Identifier:
- 318714
- Resource Type:
- Journal Article
- Journal Name:
- Environmental Science and Technology
- Additional Journal Information:
- Journal Volume: 33; Journal Issue: 2; Other Information: PBD: 15 Jan 1999
- Country of Publication:
- United States
- Language:
- English
- Subject:
- 54 ENVIRONMENTAL SCIENCES; X-RAY SPECTROSCOPY; MERCURY; SOILS; SOIL CHEMISTRY; HUMIC ACIDS; MATHEMATICAL MODELS; SULFIDES
Citation Formats
Xia, K, Skyllberg, U L, Bleam, W F, Helmke, P A, Bloom, P R, and Nater, E A. X-ray absorption spectroscopic evidence for the complexation of Hg(II) by reduced sulfur in soil humic substances. United States: N. p., 1999.
Web. doi:10.1021/es980433q.
Xia, K, Skyllberg, U L, Bleam, W F, Helmke, P A, Bloom, P R, & Nater, E A. X-ray absorption spectroscopic evidence for the complexation of Hg(II) by reduced sulfur in soil humic substances. United States. https://doi.org/10.1021/es980433q
Xia, K, Skyllberg, U L, Bleam, W F, Helmke, P A, Bloom, P R, and Nater, E A. 1999.
"X-ray absorption spectroscopic evidence for the complexation of Hg(II) by reduced sulfur in soil humic substances". United States. https://doi.org/10.1021/es980433q.
@article{osti_318714,
title = {X-ray absorption spectroscopic evidence for the complexation of Hg(II) by reduced sulfur in soil humic substances},
author = {Xia, K and Skyllberg, U L and Bleam, W F and Helmke, P A and Bloom, P R and Nater, E A},
abstractNote = {Analysis of Hg(II) complexed by a soil humic acid (HA) using synchrotron-based X-ray absorption spectroscopy (XAS) revealed the importance of reduces sulfur functional groups (thiol (R-SH) and disulfide (R-SS-R)/disulfane (R-SSH)) in humic substances in the complexation of Hg(II). A two-coordinate binding environment with one oxygen atom and one sulfur atom at distances of 2.02 and 2.38 {angstrom}, respectively, was found in the first coordination shell of Hg(II) complexed by humic acid. Model calculations show that a second coordination sphere could contain one carbon atom and a second sulfur atom at 2.78 and 2.93 {angstrom}, respectively. This suggests that in addition to thiol S, disulfide/disulfane S may be involved with the complexation of Hg(II) in soil organic matter. The appearance of carbon atom in the second coordination shell suggests that one O-containing ligand such as carboxyl and phenol ligands rather than H{sub 2}O molecule is bound to the Hg(II). The involvement of oxygen ligand in addition to the reduced S ligands in the complexation of Hg(II) is due to the low density of reduced S ligands in humic substances. The XAS results from this experiment provided direct molecular level evidence for the preference of reduced S functional groups over oxygen ligands by Hg(II) in the complexation with humic substances.},
doi = {10.1021/es980433q},
url = {https://www.osti.gov/biblio/318714},
journal = {Environmental Science and Technology},
number = 2,
volume = 33,
place = {United States},
year = {Fri Jan 15 00:00:00 EST 1999},
month = {Fri Jan 15 00:00:00 EST 1999}
}