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Biogeochemical processes in land-ocean interfaces, surface estuaries, subterranean estuaries and sediment-water interface
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Production of a non-hydroxyl radical oxidant during oxygenation of mackinawite (FeS)
Monday 7th @ 1450-1510, Conference Room 1
Jie He* , 1 Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.
2 UNSW Water Research Centre, School of Civil and Environmental Engineering, UNSW Sydney, NSW, 2052, Australia.
Christopher J. Miller, UNSW Water Research Centre, School of Civil and Environmental Engineering, UNSW Sydney, NSW, 2052, Australia.
Richard Collins, UNSW Water Research Centre, School of Civil and Environmental Engineering, UNSW Sydney, NSW, 2052, Australia.
Dongsheng Wang, Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.
T. David Waite, UNSW Water Research Centre, School of Civil and Environmental Engineering, UNSW Sydney, NSW, 2052, Australia.
Presenter Email: hejie10@mails.ucas.ac.cn |
| Iron sulfides are an intrinsic and essential part of the global biogeochemical sulfur and iron cycles. Understanding of the formation and subsequent transformations of iron sulfides is central to our understanding of the evolution of the Earth's surface environment. The oxygenation of mackinawite (FeS) frequently occurs at anoxic-oxic interfaces in both natural and engineered systems but has been rarely investigated, especially with regard to the nature and dynamics of any intermediate oxidants that may be produced. In this study, one organic compound was chosen as the probe for any oxidants produced during FeS oxygenation. Intriguingly, one compound, rather than the oxidation products by hydroxyl radical, was identified as the major oxidation product in the FeS oxygenation system but not in the hydroxyl radical-dominated systems. Both the yield order and the rate constants of the oxidation products varied dramatically in the FeS oxygenation system from those produced in the hydroxyl radical-dominated systems. We thus conclude that one or more strong oxidants that were fundamentally different from hydroxyl radical were produced during FeS oxygenation. The approximately 0.1 % yield of the total oxidant(s) produced could well be of broad environmental significance in view of the ubiquitous presence of FeS in the subsurface environment. |
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