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Title: Heterogeneous Reduction Pathways for Hg(II) Species on Dry Aerosols: A First-Principles Computational Study

Here, the atmospheric lifetime of mercury is greatly impacted by redox chemistry resulting from the high deposition rate of reactive mercury (Hg(II)) compared to elemental mercury (Hg 0). Recent laboratory and field studies have observed the reduction of Hg(II) but the chemical mechanism for this reaction has not been identified. Recent laboratory studies have shown that the reduction reaction is heterogeneous and can occur on iron and sodium chloride aerosol surfaces. This study explores the use of density functional theory calculations to discern the reduction pathways of HgCl 2, HgBr 2, Hg(NO 3) 2, and HgSO 4 on clean Fe(110), NaCl(100), and NaCl(111) Na surfaces. In doing so, potential energy surfaces have been prepared for the various reduction pathways, indicating that the reduction pathway leading to the production of gas-phase elemental mercury is highly favorable on Fe(110) and NaCl(111) Na. Moreover, the Fe(110) surface requires an external energy source of approximately 0.5 eV to desorb the reduced mercury, whereas the NaCl(111) Na surface requires no energy input. The results indicate that a number of mercury species can be reduced on metallic iron and sodium chloride surfaces, which are known aerosol components, and that a photochemical reaction involving the aerosol surfacemore » is likely needed for the reaction to be catalytic.« less
Authors:
 [1] ;  [1] ;  [1] ;  [1]
  1. Univ. of Wisconsin-Madison, Madison, WI (United States)
Publication Date:
Grant/Contract Number:
FG02-05ER15731
Type:
Accepted Manuscript
Journal Name:
Journal of Physical Chemistry. A, Molecules, Spectroscopy, Kinetics, Environment, and General Theory
Additional Journal Information:
Journal Volume: 120; Journal Issue: 13; Journal ID: ISSN 1089-5639
Publisher:
American Chemical Society
Research Org:
Univ. of Wisconsin-Madison, Madison, WI (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
Language:
English
Subject:
54 ENVIRONMENTAL SCIENCES
OSTI Identifier:
1395564

Tacey, Sean A., Xu, Lang, Mavrikakis, Manos, and Schauer, James J.. Heterogeneous Reduction Pathways for Hg(II) Species on Dry Aerosols: A First-Principles Computational Study. United States: N. p., Web. doi:10.1021/acs.jpca.5b12769.
Tacey, Sean A., Xu, Lang, Mavrikakis, Manos, & Schauer, James J.. Heterogeneous Reduction Pathways for Hg(II) Species on Dry Aerosols: A First-Principles Computational Study. United States. doi:10.1021/acs.jpca.5b12769.
Tacey, Sean A., Xu, Lang, Mavrikakis, Manos, and Schauer, James J.. 2016. "Heterogeneous Reduction Pathways for Hg(II) Species on Dry Aerosols: A First-Principles Computational Study". United States. doi:10.1021/acs.jpca.5b12769. https://www.osti.gov/servlets/purl/1395564.
@article{osti_1395564,
title = {Heterogeneous Reduction Pathways for Hg(II) Species on Dry Aerosols: A First-Principles Computational Study},
author = {Tacey, Sean A. and Xu, Lang and Mavrikakis, Manos and Schauer, James J.},
abstractNote = {Here, the atmospheric lifetime of mercury is greatly impacted by redox chemistry resulting from the high deposition rate of reactive mercury (Hg(II)) compared to elemental mercury (Hg0). Recent laboratory and field studies have observed the reduction of Hg(II) but the chemical mechanism for this reaction has not been identified. Recent laboratory studies have shown that the reduction reaction is heterogeneous and can occur on iron and sodium chloride aerosol surfaces. This study explores the use of density functional theory calculations to discern the reduction pathways of HgCl2, HgBr2, Hg(NO3)2, and HgSO4 on clean Fe(110), NaCl(100), and NaCl(111)Na surfaces. In doing so, potential energy surfaces have been prepared for the various reduction pathways, indicating that the reduction pathway leading to the production of gas-phase elemental mercury is highly favorable on Fe(110) and NaCl(111)Na. Moreover, the Fe(110) surface requires an external energy source of approximately 0.5 eV to desorb the reduced mercury, whereas the NaCl(111)Na surface requires no energy input. The results indicate that a number of mercury species can be reduced on metallic iron and sodium chloride surfaces, which are known aerosol components, and that a photochemical reaction involving the aerosol surface is likely needed for the reaction to be catalytic.},
doi = {10.1021/acs.jpca.5b12769},
journal = {Journal of Physical Chemistry. A, Molecules, Spectroscopy, Kinetics, Environment, and General Theory},
number = 13,
volume = 120,
place = {United States},
year = {2016},
month = {3}
}