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Wang S, Liao P, Cen L, Cheng H, Liu Q. Biochar Promotes Arsenopyrite Weathering in Simulated Alkaline Soils: Electrochemical Mechanism and Environmental Implications. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023. [PMID: 37224024 DOI: 10.1021/acs.est.2c09874] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Oxidation dissolution of arsenopyrite (FeAsS) is one of the important sources of arsenic contamination in soil and groundwater. Biochar, a commonly used soil amendment and environmental remediation agent, is widespread in ecosystems, where it participates in and influences the redox-active geochemical processes of sulfide minerals associated with arsenic and iron. This study investigated the critical role of biochar on the oxidation process of arsenopyrite in simulated alkaline soil solutions by a combination of electrochemical techniques, immersion tests, and solid characterizations. Polarization curves indicated that the elevated temperature (5-45 °C) and biochar concentration (0-1.2 g·L-1) accelerated arsenopyrite oxidation. This is further confirmed by electrochemical impedance spectroscopy, which showed that biochar substantially reduced the charge transfer resistance in the double layer, resulting in smaller activation energy (Ea = 37.38-29.56 kJ·mol-1) and activation enthalpy (ΔH* = 34.91-27.09 kJ·mol-1). These observations are likely attributed to the abundance of aromatic and quinoid groups in biochar, which could reduce Fe(III) and As(V) as well as adsorb or complex with Fe(III). This hinders the formation of passivation films consisting of iron arsenate and iron (oxyhydr)oxide. Further observation found that the presence of biochar exacerbates acidic drainage and arsenic contamination in areas containing arsenopyrite. This study highlighted the possible negative impact of biochar on soil and water, suggesting that the different physicochemical properties of biochar produced from different feedstock and under different pyrolysis conditions should be taken into account before large-scale applications to prevent potential risks to ecology and agriculture.
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Affiliation(s)
- Shuai Wang
- Key Laboratory of High-temperature and High-pressure Study of the Earth's Interior, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
- University of Chinese Academy of Sciences, Beijing 100039, China
| | - Peng Liao
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
| | - Ling Cen
- Key Laboratory of High-temperature and High-pressure Study of the Earth's Interior, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
- University of Chinese Academy of Sciences, Beijing 100039, China
| | - Hongguang Cheng
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
| | - Qingyou Liu
- Key Laboratory of High-temperature and High-pressure Study of the Earth's Interior, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
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Zhou S, Gan M, Wang X, Zhang Y, Fang Y, Gu G, Wang Y, Qiu G. ROS formation driven by pyrite-mediated arsenopyrite oxidation and its potential role on arsenic transformation. JOURNAL OF HAZARDOUS MATERIALS 2023; 443:130151. [PMID: 36270187 DOI: 10.1016/j.jhazmat.2022.130151] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2022] [Revised: 09/13/2022] [Accepted: 10/06/2022] [Indexed: 06/16/2023]
Abstract
Pyrite-mediated arsenopyrite oxidation is an important process affecting arsenic (As) mobility. The iron sulfides-induced reactive oxidation species (ROS) can exert significant influence on As transformation. However, the impact of pyrite-arsenopyrite association on ROS production and its contribution to As transformation were rarely estimated. Here, ROS formation and the redox conversion of As during the interaction between pyrite and arsenopyrite as function of O2, pH and pyrite surface oxidation were investigated. Pyrite promoted arsenopyrite oxidation and As(III) oxidation due to heterogeneous electron transfer. The electron transfer from arsenopyrite facilitated O2 reduction on pyrite surface with increasing ROS formation. Hydroxyl radical (HO˙), superoxide (O2•)- and hydrogen peroxide (H2O2) were the main reactive species for As(III) oxidation. Iron (hydr)oxides produced from pyrite surface oxidation provided fast electron transfer channels for efficient O2 reduction as evidenced by electrochemical experiment, further verifying the promoted effect of surface-oxidized pyrite (SOP) on arsenopyrite dissolution. However, total As and As(V) obviously decreased during SOP-mediated arsenopyrite oxidation. Iron (hydr)oxides retained appreciable As through adsorption to limit its mobility, and decreased HO˙ production to inhibit As(III) oxidation via decomposing H2O2. This work furthers our understanding of arsenic transformation in the environment which has important implications for mitigating arsenic pollution.
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Affiliation(s)
- Shuang Zhou
- School of Minerals Processing and Bioengineering, Key Laboratory of Biometallurgy of Ministry of Education, Central South University, Changsha 410083, China; State Environmental Protection Key Laboratory of Mineral Metallurgical Resources Utilization and Pollution Control, Wuhan University of Science and Technology, Wuhan 430081, China
| | - Min Gan
- School of Minerals Processing and Bioengineering, Key Laboratory of Biometallurgy of Ministry of Education, Central South University, Changsha 410083, China; Hunan Engineering Technology Research Center for Treatment and Recycling of Heavy Pollution Industrial Wastewater, Changsha 410083, China
| | - Xingxing Wang
- School of Minerals Processing and Bioengineering, Key Laboratory of Biometallurgy of Ministry of Education, Central South University, Changsha 410083, China
| | - Yisheng Zhang
- School of Minerals Processing and Bioengineering, Key Laboratory of Biometallurgy of Ministry of Education, Central South University, Changsha 410083, China
| | - Yingchun Fang
- Hunan Engineering Technology Research Center for Treatment and Recycling of Heavy Pollution Industrial Wastewater, Changsha 410083, China
| | - Guohua Gu
- School of Minerals Processing and Bioengineering, Key Laboratory of Biometallurgy of Ministry of Education, Central South University, Changsha 410083, China.
| | - Yanhong Wang
- School of Minerals Processing and Bioengineering, Key Laboratory of Biometallurgy of Ministry of Education, Central South University, Changsha 410083, China.
| | - Guanzhou Qiu
- School of Minerals Processing and Bioengineering, Key Laboratory of Biometallurgy of Ministry of Education, Central South University, Changsha 410083, China
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Cen L, Cheng H, Liu Q, Wang S, Wang X. Arsenic release from arsenopyrite weathering in acid mine drainage: Kinetics, transformation, and effect of biochar. ENVIRONMENT INTERNATIONAL 2022; 170:107558. [PMID: 36202015 DOI: 10.1016/j.envint.2022.107558] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/22/2022] [Revised: 09/29/2022] [Accepted: 09/30/2022] [Indexed: 06/16/2023]
Abstract
Arsenopyrite (FeAsS) oxidative dissolution provides an important source for the occurrence of high arsenic in acid mine drainage (AMD). Biochar is a potent material that can dramatically sequestrate an array of heavy metals in water. However, little is known about the role of biochar on the fate of As from arsenopyrite in AMD. This study investigates the effects of biochar concentrations, AMD acidities, and temperatures on the release of As from arsenopyrite in a simulated AMD over a range of environmentally relevant conditions. Results show that biochar inhibits As release and further acidification without changing the arsenopyrite weathering mechanism. Arsenopyrite is first oxidized to Fe(II), As(III) and S0 and ultimately oxidized to Fe(III), As(V) and SO42-, respectively. Higher concentration, temperature or higher acidity promotes the arsenic release rate. Electrochemical studies showed that biochar inhibited As release and acidification for reduced the charge transfer resistance at the double layer and film resistance at the passivation layer, which was mainly attributed to Fe(III) ions in AMD being adsorbed, oxidized, and As complexed to biochar-Fe-As(V). This study reveals the release mechanism of As from arsenopyrite weathering in AMD and suggests the applicability of biochar in mitigating arsenic pollution and further acidification in sulfide mineral mine drainage.
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Affiliation(s)
- Ling Cen
- Key Laboratory of High-temperature and High-pressure Study of the Earth's Interior, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China; University of Chinese Academy of Sciences, Beijing 100039, China
| | - Hongguang Cheng
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
| | - Qingyou Liu
- Key Laboratory of High-temperature and High-pressure Study of the Earth's Interior, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China.
| | - Shuai Wang
- Key Laboratory of High-temperature and High-pressure Study of the Earth's Interior, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China; University of Chinese Academy of Sciences, Beijing 100039, China
| | - Xi Wang
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China; University of Chinese Academy of Sciences, Beijing 100039, China
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Kuang J, Qi S, Shi C, Qu C. Supergene geochemistry of arsenic and activation mechanism of eucalyptus to arsenic source. ENVIRONMENTAL GEOCHEMISTRY AND HEALTH 2022; 44:4017-4029. [PMID: 34812976 DOI: 10.1007/s10653-021-01155-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Accepted: 11/04/2021] [Indexed: 06/13/2023]
Abstract
Arsenic (As) migration and transformation in the supergene environment and eucalyptus planting have essential effects on ecology or even human health, respectively. However, the combined environmental impact of As migration and transformation and eucalyptus planting has not been studied. Here we report a case of soil As contamination caused by eucalyptus planting and address the fate of As in Longmen county, Guangdong Province, China. We found high As content in weathered arsenopyrite bearing granite or granite-derived soil, where a large area of eucalyptus is planted. The release of organic acids from eucalyptus roots promoted the electrochemical reaction of arsenopyrite to produce AsO33-. In the subsequent supergene migration process, As species change from arsenite to arsenate with the addition of oxygen and the effect of clay minerals, last with As infiltration, precipitation, and enrichment, forming the As contamination in soil. The whole process reveals the activation process of eucalyptus to the As source (arsenopyrite), the migration and transformation process of As in the supergene environment, and the formation mechanism of soil As contamination. This finding provides a new perspective of soil As contamination around arsenopyrite bearing granite of the Nanling area with eucalyptus planting and proposes that the negative effects of Nanling eucalyptus planting may be greater than expected.
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Affiliation(s)
- Jian Kuang
- State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Wuhan, 430074, China
| | - Shihua Qi
- State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Wuhan, 430074, China.
| | - Changhe Shi
- State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Wuhan, 430074, China
| | - Chengkai Qu
- State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Wuhan, 430074, China
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Chen HR, Zhang DR, Li Q, Nie ZY, Pakostova E. Release and fate of As mobilized via bio-oxidation of arsenopyrite in acid mine drainage: Importance of As/Fe/S speciation and As(III) immobilization. WATER RESEARCH 2022; 223:118957. [PMID: 35970106 DOI: 10.1016/j.watres.2022.118957] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/03/2022] [Revised: 08/03/2022] [Accepted: 08/06/2022] [Indexed: 06/15/2023]
Abstract
Mining activities expose sulfidic minerals including arsenopyrite (FeAsS) to acid mine drainage (AMD). The subsequent release of toxic arsenic (As) can have great negative implications for the environment and human health. This study investigated the evolution of secondary products and As speciation transformations during arsenopyrite bio-oxidation in AMD collected from a polymetallic mine. Immobilization of the As solubilized via arsenopyrite bio-oxidation using red mud (RM) was also studied. The results show that the high ionic strength (concentrations of dissolved Fe3+, SO42-, and Ca2+ reached values up to 0.75, 3.38, and 0.35 g/L, respectively) and redox potential (up to +621 mV) of AMD (caused primarily by Fe3+) enhanced the dissolution of arsenopyrite. A high [Fe]aq/[As]aq ratio in the AMD favored the precipitation of tooeleite during arsenopyrite bio-oxidation, and the formation of other poorly crystalline products such as schwertmannite and amorphous ferric arsenate also contributed to As immobilization. Bacterial cells served as important nucleation sites for the precipitation of mineral phases. Arsenopyrite completely dissolved after 12 days of bio-oxidation in AMD and the [As]aq (mainly present as As(III)) reached 1.92 g/L, while a greater [As]aq was observed in a basal salts medium (BSM) assay (reaching 3.02 g/L). An RM addition significantly promoted As(III) immobilization, with final [As(III)]aq decreasing to 0.16 and 1.43 g/L in AMD and BSM assays respectively. No oxidation of As(III) was detected during the immobilization process. These findings can help predict As release from arsenopyrite on contact with AMD and, on a broader scale, assist in designing remediation and treatment strategies to mitigate As contamination in mining.
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Affiliation(s)
- Hong-Rui Chen
- School of Minerals Processing and Bioengineering, Central South University, Changsha 410083, China
| | - Duo-Rui Zhang
- School of Minerals Processing and Bioengineering, Central South University, Changsha 410083, China.
| | - Qian Li
- School of Minerals Processing and Bioengineering, Central South University, Changsha 410083, China.
| | - Zhen-Yuan Nie
- School of Minerals Processing and Bioengineering, Central South University, Changsha 410083, China
| | - Eva Pakostova
- Centre for Sport, Exercise and Life Sciences, Coventry University, Coventry CV1 5FB, UK
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Hong J, Liu L, Zhang Z, Xia X, Yang L, Ning Z, Liu C, Qiu G. Sulfate-accelerated photochemical oxidation of arsenopyrite in acidic systems under oxic conditions: Formation and function of schwertmannite. JOURNAL OF HAZARDOUS MATERIALS 2022; 433:128716. [PMID: 35358816 DOI: 10.1016/j.jhazmat.2022.128716] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/08/2022] [Revised: 03/12/2022] [Accepted: 03/13/2022] [Indexed: 06/14/2023]
Abstract
The weathering of arsenopyrite is closely related to the generation of acid mine drainage (AMD) and arsenic (As) pollution. Solar radiation can accelerate arsenopyrite oxidation, but little is known about the further effect of SO42- on the photochemical process. Here, the photooxidation of arsenopyrite was investigated in the presence of SO42- in simulated AMD environments, and the effects of SO42- concentration, pH and dissolved oxygen on arsenopyrite oxidation were studied as well. SO42- could accelerate the photooxidation of arsenopyrite and As(III) through complexation between nascent schwertmannite and As(III). Fe(II) released from arsenopyrite was oxidized to form schwertmannite in the presence of SO42-, and the photooxidation of arsenopyrite occurred through the ligand-to-metal charge-transfer process in schwertmannite-As(III) complex along with the formation of reactive oxygen species in the presence of O2. The photooxidation rate of arsenopyrite first rose and then fell with increasing SO42- concentration. In the pH range of 2.0-4.0, the photooxidation rate of arsenopyrite progressively increased in the presence of SO42-. This study reveals how SO42- promotes the photooxidation of arsenopyrite and As release in the AMD environment, and improves the understanding of the transformation and migration of As in mining areas.
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Affiliation(s)
- Jun Hong
- Key Laboratory of Fertilization from Agricultural Wastes, Ministry of Agriculture and Rural Affairs, Institute of Plant Protection and Soil Fertilizer, Hubei Academy of Agricultural Sciences, Wuhan 430070, Hubei Province, China; College of Resources and Environment, Interdisciplinary Sciences Institute, Huazhong Agricultural University, Wuhan 430070, Hubei Province, China
| | - Lihu Liu
- College of Resources and Environment, Interdisciplinary Sciences Institute, Huazhong Agricultural University, Wuhan 430070, Hubei Province, China
| | - Ziwei Zhang
- College of Resources and Environment, Interdisciplinary Sciences Institute, Huazhong Agricultural University, Wuhan 430070, Hubei Province, China
| | - Xiange Xia
- Key Laboratory of Fertilization from Agricultural Wastes, Ministry of Agriculture and Rural Affairs, Institute of Plant Protection and Soil Fertilizer, Hubei Academy of Agricultural Sciences, Wuhan 430070, Hubei Province, China.
| | - Li Yang
- Key Laboratory of Fertilization from Agricultural Wastes, Ministry of Agriculture and Rural Affairs, Institute of Plant Protection and Soil Fertilizer, Hubei Academy of Agricultural Sciences, Wuhan 430070, Hubei Province, China
| | - Zengping Ning
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, Guizhou Province, China
| | - Chengshuai Liu
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, Guizhou Province, China
| | - Guohong Qiu
- College of Resources and Environment, Interdisciplinary Sciences Institute, Huazhong Agricultural University, Wuhan 430070, Hubei Province, China.
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Hong J, Liu L, Ning Z, Liu C, Qiu G. Synergistic oxidation of dissolved As(III) and arsenopyrite in the presence of oxygen: Formation and function of reactive oxygen species. WATER RESEARCH 2021; 202:117416. [PMID: 34284121 DOI: 10.1016/j.watres.2021.117416] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/11/2021] [Revised: 07/02/2021] [Accepted: 07/03/2021] [Indexed: 06/13/2023]
Abstract
As an important source of arsenic (As) pollution in mine drainage, arsenopyrite undergoes redox and adsorption reactions with dissolved As, which further affects the fate of As in natural waters. This study investigated the interactions between dissolved As(III) and arsenopyrite and the factors influencing the geochemical behavior of As, including initial As(III) concentration, dissolved oxygen and pH. The hydrogen peroxide (H2O2) and hydroxyl radical (OH•) generated from the interaction between Fe(II) on arsenopyrite surface and oxygen were found to facilitate the rapid oxidation of As(III), and the production of As(V) in the reaction system increased with increasing initial As(III) concentration. An increase of pH from 3.0 to 7.0 led to a gradual decrease in the oxidation rate of As(III). At pH 3.0, the presence of As(III) accelerated the oxidation rate of arsenopyrite; while at pH 5.0 and 7.0, As(III) inhibited the oxidative dissolution of arsenopyrite. This work reveals the potential environmental process of the interaction between dissolved As(III) and arsenopyrite, and provides important implications for the prevention and control of As(III) pollution in mine drainage.
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Affiliation(s)
- Jun Hong
- Key Laboratory of Arable Land Conservation (Middle and Lower Reaches of Yangtse River), State Environmental Protection Key Laboratory of Soil Health and Green Remediation, Hubei Key Laboratory of Soil Environment and Pollution Remediation, Ministry of Agriculture, College of Resources and Environment, Huazhong Agricultural University, Wuhan, Hubei 430070, China
| | - Lihu Liu
- Key Laboratory of Arable Land Conservation (Middle and Lower Reaches of Yangtse River), State Environmental Protection Key Laboratory of Soil Health and Green Remediation, Hubei Key Laboratory of Soil Environment and Pollution Remediation, Ministry of Agriculture, College of Resources and Environment, Huazhong Agricultural University, Wuhan, Hubei 430070, China
| | - Zengping Ning
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, Guizhou 550081, China
| | - Chengshuai Liu
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, Guizhou 550081, China
| | - Guohong Qiu
- Key Laboratory of Arable Land Conservation (Middle and Lower Reaches of Yangtse River), State Environmental Protection Key Laboratory of Soil Health and Green Remediation, Hubei Key Laboratory of Soil Environment and Pollution Remediation, Ministry of Agriculture, College of Resources and Environment, Huazhong Agricultural University, Wuhan, Hubei 430070, China.
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