title: Stable isotope composition of mercury forms in flue gases from a typical coal-fired power plant, Inner Mongolia, northern China.
abstract: Mercury forms emitted from coal combustion via air pollution control devices are speculated to carry different Hg isotope signatures. Yet, their Hg isotope composition is still not reported. Here, we present the first onsite Hg isotope data for gaseous elemental Hg (GEM) and gaseous oxidized Hg (GOM) of flue gases from a typical lignite-fired power plant (CFPP). Significant mass dependent fractionation (MDF) and insignificant mass independent fractionation (MIF) are observed between feed coal and coal combustion products. As compared to feed coal (δ202Hg=-2.04±0.25‰), bottom ash, GEM and GOM in flue gases before and after wet flue gas desulfurization system significantly enrich heavy Hg isotopes by 0.7-2.6‰ in δ202Hg, while fly ash, desulfurization gypsum and waste water show slight but insignificant enrichment of light Hg isotopes. GEM is significantly enriched heavy Hg isotopes compared to GOM and Hg in fly ash. Our observations verify the previous speculation on Hg isotope fractionation mechanism in CFPPs, and suggest a kinetically-controlled mass dependent Hg isotope fractionation during transformation of Hg forms in flue gases. Finally, our data are compared to Hg isotope compositions of atmospheric Hg pools, suggesting that coal combustion Hg emission is likely an important atmospheric Hg contributor.
authors.affiliation: Institute of Resources and Environment, Henan Polytechnic University, Jiaozuo, Henan Province, 454000, China. Electronic address: tangshunlin@hpu.edu.cn.
authors.forename: Shunlin
authors.initials: S
authors.lastname: Tang
authors.affiliation: Institute of Resources and Environment, Henan Polytechnic University, Jiaozuo, Henan Province, 454000, China.
authors.forename: Chaohui
authors.initials: C
authors.lastname: Feng
authors.affiliation: State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, 550002, China.
authors.forename: Xinbin
authors.initials: X
authors.lastname: Feng
authors.affiliation: Institute of Resources and Environment, Henan Polytechnic University, Jiaozuo, Henan Province, 454000, China; State Key Laboratory of Geological Processes and Mineral Resources, China University of Geosciences, Beijing, 100086, China.
authors.forename: Jianming
authors.initials: J
authors.lastname: Zhu
authors.affiliation: CAS Key Laboratory of Crust-Mantle Materials and Environment, School of Earth and Space Sciences, University of Science and Technology of China, Hefei, Anhui 230026, China. Electronic address: ruoyu.sun@tju.edu.cn.
authors.forename: Ruoyu
authors.initials: R
authors.lastname: Sun
authors.affiliation: Institute of Resources and Environment, Henan Polytechnic University, Jiaozuo, Henan Province, 454000, China.
authors.forename: Huipeng
authors.initials: H
authors.lastname: Fan
authors.affiliation: Institute of Resources and Environment, Henan Polytechnic University, Jiaozuo, Henan Province, 454000, China.
authors.forename: Lina
authors.initials: L
authors.lastname: Wang
authors.affiliation: Institute of Resources and Environment, Henan Polytechnic University, Jiaozuo, Henan Province, 454000, China.
authors.forename: Ruiyang
authors.initials: R
authors.lastname: Li
authors.affiliation: Institute of Resources and Environment, Henan Polytechnic University, Jiaozuo, Henan Province, 454000, China.
authors.forename: Tonghua
authors.initials: T
authors.lastname: Mao
authors.affiliation: State Key Laboratory of Ore Deposit Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, 550002, China.
authors.forename: Ting
authors.initials: T
authors.lastname: Zhou
keywords: Coal-fired power plant; Mass dependent fractionation; Mercury forms; Mercury isotope