New insights into the controversy of reactive mineral-controlled arsenopyrite dissolution and arsenic release.

Autor: Qu H; School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou 510006, PR China; Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, Sun Yat-sen University, Guangzhou 510006, PR China., Ding K; School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou 510006, PR China; Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, Sun Yat-sen University, Guangzhou 510006, PR China., Ao M; School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou 510006, PR China; Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, Sun Yat-sen University, Guangzhou 510006, PR China., Ye Z; School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou 510006, PR China; Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, Sun Yat-sen University, Guangzhou 510006, PR China., Liu T; School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou 510006, PR China; Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, Sun Yat-sen University, Guangzhou 510006, PR China., Hu Z; Guangdong Provincial Key Laboratory of Agricultural & Rural Pollution Abatement and Environmental Safety, College of Natural Resources and Environment, South China Agricultural University, Guangzhou 510642, PR China., Cao Y; School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou 510006, PR China., Morel JL; School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou 510006, PR China; Université de Lorraine, INRAE, LSE, F-54000 Nancy, France., Baker AJM; Université de Lorraine, INRAE, LSE, F-54000 Nancy, France; School of BioSciences, The University of Melbourne, Parkville VIC3010, Australia., Tang Y; School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou 510006, PR China; Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, Sun Yat-sen University, Guangzhou 510006, PR China., Qiu R; School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou 510006, PR China; Guangdong Provincial Key Laboratory of Agricultural & Rural Pollution Abatement and Environmental Safety, College of Natural Resources and Environment, South China Agricultural University, Guangzhou 510642, PR China; Guangdong Laboratory for Lingnan Modern Agriculture, South China Agricultural University, Guangzhou 510642, PR China., Wang S; School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou 510006, PR China; Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, Sun Yat-sen University, Guangzhou 510006, PR China. Electronic address: wshizh2@mail.sysu.edu.cn.
Jazyk: angličtina
Zdroj: Water research [Water Res] 2024 Sep 15; Vol. 262, pp. 122051. Date of Electronic Publication: 2024 Jul 05.
DOI: 10.1016/j.watres.2024.122051
Abstrakt: Serious arsenic (As) contaminations could commonly result from the oxidative dissolution of As-containing sulfide minerals, such as arsenopyrite (FeAsS). Pyrite (Py) and calcite (Cal) are two typically co-existing reactive minerals and represent different geological scenarios. Previous studies have shown that a high proportion of Py can generate a stronger galvanic effect and acid dissolution, thereby significantly promoting the release of arsenic. However, this conclusion overlooks calcite's antagonistic effect on the release of As in the natural environment. That antagonistic effect could remodel the linear relationship of pyrite on the oxidative dissolution of arsenopyrite, thus altering the environmental risk of As. We examined As release from arsenopyrite along a gradient of Py to Cal molar ratios (Py:Cal). The results showed that the lowest As release from arsenopyrite was surprisingly found in co-existing Py and Cal systems than in the singular Cal system, let alone in the singular Py system. This phenomenon indicated an interesting possibility of Py assistance to Cal inhibition of As release, though Py has always been regarded as a booster, also evidenced in this research, for As release from arsenopyrite. In singular systems of Py and Cal, As continued to be released for 60 days. However, in co-existing Py and Cal systems, As was released non-linearly in three stages over time: initial release (0-1 Day), immobilization (1-15 Days), and subsequent re-release (>15 Days). This is a new short-term natural attenuation stage for As, but over time, this stage gradually collapses. During the re-release stage (> 15 Days), a higher molar ratio of Py:Cal (increasing from 1:9 to 9:1) results in a lower rate constant k (mg·L -1 ·h -1 ) of As release (range from 0.0011 to 0.0002), and a higher abundance of secondary minerals formed (up to 26 mg/g goethite and hematite at Py: Cal=9:1). This demonstrates that increasing the Py:Cal molar ratio results in the formation of more secondary minerals which compensate for the higher potential antagonistic mechanisms generated by pyrites, such as acid dissolution and galvanic effect. These results explain the mechanisms of the high-risk characteristics of As both in acidic mine drainage and karst aquifers and discover the lowest risk in pyrite and calcite co-existing regions. Moreover, we emphasize that reactive minerals are important variables that can't be ignored in predicting As pollution in the future.
Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
(Copyright © 2024. Published by Elsevier Ltd.)
Databáze: MEDLINE
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