Physics Department, Illinois Institute of Technology, Chicago, Illinois 60616, United States
Biosciences Division, Argonne National Laboratory, Lemont, Illinois 60439, United States; Institute of Chemical Engineering, Bulgarian Academy of Sciences, Sofia, Bulgaria, 1113
Biosciences Division, Argonne National Laboratory, Lemont, Illinois 60439, United States
The reduction of HgII to HgI or Hg0 can lead to significant changes in Hg toxicity and mobility in the environment. Photochemical reduction is the primary process for the reduction of HgII to Hg0 in sunlit environments; however, dark reduction of HgII can occur via microbial metabolic processes and/or reduction by reduced natural organic matter, FeII mineral phases, FeII sorbed to minerals, or aqueous FeII. Here, in this study, we demonstrate a novel HgII reduction pathway involving another environmentally relevant reductant, MnII. Abiotic reduction of HgIIO by MnII was studied as a function of pH and anion environment (perchlorate, sulfate, chloride) using X-ray absorption spectroscopy to characterize the solid-phase Hg and Mn species. At circumneutral pH of 7.5, about 70% of HgII was reduced to elemental Hg0 within 2 h. In contrast, 12 h were needed to achieve the same extent of reduction at pH 6.9. In the presence of sulfate and chloride, HgI species were formed. HgII reduction was initially rapid and coupled with the oxidation of soluble MnII-oxides to insoluble MnIV-oxides, followed by a significantly slower reduction of HgII during the MnII-catalyzed transformation of the MnIV-oxides to hydroxide and oxyhydroxide minerals. The observed reduction of HgII by MnII at circumneutral pH could be an important transformation pathway for environmental Hg, affecting its bioavailability and mobility under mildly reducing conditions.
Mishra, Bhoopesh, et al. "Reduction of Hg<sup>II</sup>by Mn<sup>II</sup>." ACS Earth and Space Chemistry, vol. 8, no. 6, Jun. 2024. https://doi.org/10.1021/acsearthspacechem.3c00304
Mishra, Bhoopesh, Boyanov, Maxim I., Kemner, Kenneth M., & O’Loughlin, Edward J. (2024). Reduction of Hg<sup>II</sup>by Mn<sup>II</sup>. ACS Earth and Space Chemistry, 8(6). https://doi.org/10.1021/acsearthspacechem.3c00304
Mishra, Bhoopesh, Boyanov, Maxim I., Kemner, Kenneth M., et al., "Reduction of Hg<sup>II</sup>by Mn<sup>II</sup>," ACS Earth and Space Chemistry 8, no. 6 (2024), https://doi.org/10.1021/acsearthspacechem.3c00304
@article{osti_2468631,
author = {Mishra, Bhoopesh and Boyanov, Maxim I. and Kemner, Kenneth M. and O’Loughlin, Edward J.},
title = {Reduction of Hg<sup>II</sup>by Mn<sup>II</sup>},
annote = {The reduction of HgII to HgI or Hg0 can lead to significant changes in Hg toxicity and mobility in the environment. Photochemical reduction is the primary process for the reduction of HgII to Hg0 in sunlit environments; however, dark reduction of HgII can occur via microbial metabolic processes and/or reduction by reduced natural organic matter, FeII mineral phases, FeII sorbed to minerals, or aqueous FeII. Here, in this study, we demonstrate a novel HgII reduction pathway involving another environmentally relevant reductant, MnII. Abiotic reduction of HgIIO by MnII was studied as a function of pH and anion environment (perchlorate, sulfate, chloride) using X-ray absorption spectroscopy to characterize the solid-phase Hg and Mn species. At circumneutral pH of 7.5, about 70% of HgII was reduced to elemental Hg0 within 2 h. In contrast, 12 h were needed to achieve the same extent of reduction at pH 6.9. In the presence of sulfate and chloride, HgI species were formed. HgII reduction was initially rapid and coupled with the oxidation of soluble MnII-oxides to insoluble MnIV-oxides, followed by a significantly slower reduction of HgII during the MnII-catalyzed transformation of the MnIV-oxides to hydroxide and oxyhydroxide minerals. The observed reduction of HgII by MnII at circumneutral pH could be an important transformation pathway for environmental Hg, affecting its bioavailability and mobility under mildly reducing conditions.},
doi = {10.1021/acsearthspacechem.3c00304},
url = {https://www.osti.gov/biblio/2468631},
journal = {ACS Earth and Space Chemistry},
issn = {ISSN 2472-3452},
number = {6},
volume = {8},
place = {United States},
publisher = {American Chemical Society (ACS)},
year = {2024},
month = {06}}
Argonne National Laboratory (ANL), Argonne, IL (United States)
Sponsoring Organization:
USDOE Office of Science (SC), Basic Energy Sciences (BES). Scientific User Facilities (SUF); USDOE Office of Science (SC), Biological and Environmental Research (BER). Earth & Environmental Systems Science (EESS)
Grant/Contract Number:
AC02-06CH11357
OSTI ID:
2468631
Alternate ID(s):
OSTI ID: 2468632
Journal Information:
ACS Earth and Space Chemistry, Journal Name: ACS Earth and Space Chemistry Journal Issue: 6 Vol. 8; ISSN 2472-3452