Evaluating the role of re-adsorption of dissolved Hg(2+) during cinnabar dissolution using isotope tracer technique.
Cinnabar dissolution is an important factor controlling mercury (Hg) cycling. Recent studies have suggested the co-occurrence of re-adsorption of the released Hg during the course of cinnabar dissolution. However, there is a lack of feasible techniques that can quantitatively assess the amount of Hg re-adsorbed on cinnabar when investigating cinnabar dissolution. In this study, a new method, based on isotope tracing and dilution techniques, was developed to study the role of Hg re-adsorption in cinnabar dissolution. The developed method includes two key components: (1) accurate measurement of both released and spiked Hg in aqueous phase and (2) estimation of re-adsorbed Hg on cinnabar surface via the reduction in spiked (202)Hg(2+). By adopting the developed method, it was found that the released Hg for trials purged with oxygen could reach several hundred μgL(-1), while no significant cinnabar dissolution was detected under anaerobic condition. Cinnabar dissolution rate when considering Hg re-adsorption was approximately 2 times the value calculated solely with the Hg detected in the aqueous phase. These results suggest that ignoring the Hg re-adsorption process can significantly underestimate the importance of cinnabar dissolution, highlighting the necessity of applying the developed method in future cinnabar dissolution studies.
Department of Chemistry and Biochemistry, Florida International University, Miami, FL 33199, USA.
Ping
P
Jiang
Key Laboratory of Marine Chemistry Theory and Technology, Ministry of Education/Qingdao Collaborative Innovation Center of Marine Science and Technology, Ocean University of China, Qingdao 266100, China.
Yanbin
Y
Li
Department of Chemistry and Biochemistry, Florida International University, Miami, FL 33199, USA; Southeast Environmental Research Center, Florida International University, Miami, FL 33199, USA.
Guangliang
G
Liu
College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou 350002, China.
Guidi
G
Yang
Applied Research Center, Florida International University, Miami, FL 33199, USA.
Leonel
L
Lagos
State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.
Yongguang
Y
Yin
Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge TN 37831, USA.
Baohua
B
Gu
State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.
Guibin
G
Jiang
Department of Chemistry and Biochemistry, Florida International University, Miami, FL 33199, USA; Southeast Environmental Research Center, Florida International University, Miami, FL 33199, USA. Electronic address: cai@fiu.edu.
Yong
Y
Cai
Cinnabar dissolution; Hg re-adsorption on cinnabar surface; Isotope dilution; Isotope tracer technique; Redox condition