title: Catalytic effect of Ag⁺ on arsenic bioleaching from orpiment (As₂S₃) in batch tests with Acidithiobacillus ferrooxidans and Sulfobacillus sibiricus.
abstract: Orpiment is one of the major arsenic sulfide minerals which commonly occurs in the gold mine environment and the weathering of this mineral can lead to the contamination of arsenic. In this study, chemical leaching experiments using 10g/L Fe(3+) at 35°C and 50°C were carried out and the results show that orpiment can be leached by Fe(3+) and the leaching rate of orpiment was significantly enhanced in the presence of Ag(+). The bioleaching experiments with mesophilic bacteria Acidithiobacillus ferrooxidans and moderate thermophilic bacteria Sulfobacillus sibiricus were carried out, showing that these two strains can survive in the mineral pulp and oxidize Fe(2+) to regenerate Fe(3+). Based on above results, it is believed that the leaching action of the acidic mining drainage by some bacteria can lead to the release of arsenic from orpiment. Different performances of At. ferrooxidans and S. sibiricus in the tests suggest they follow two different mechanisms and this point of view is further confirmed based on analyses of the composition and morphology of the mineral residue by SEM and EDS.
authors.affiliation: National Key Laboratory of Biochemical Engineering and Key Laboratory of Green Process and Engineering, Institute of Processing Engineering, Chinese Academy of Sciences, Beijing 100190, China.
authors.forename: Guangji
authors.initials: G
authors.lastname: Zhang
authors.affiliation: National Key Laboratory of Biochemical Engineering and Key Laboratory of Green Process and Engineering, Institute of Processing Engineering, Chinese Academy of Sciences, Beijing 100190, China; China University of Petroleum-Beijing, Beijing 102249, China.
authors.forename: Xingwu
authors.initials: X
authors.lastname: Chao
authors.affiliation: National Key Laboratory of Biochemical Engineering and Key Laboratory of Green Process and Engineering, Institute of Processing Engineering, Chinese Academy of Sciences, Beijing 100190, China.
authors.forename: Pei
authors.initials: P
authors.lastname: Guo
authors.affiliation: National Key Laboratory of Biochemical Engineering and Key Laboratory of Green Process and Engineering, Institute of Processing Engineering, Chinese Academy of Sciences, Beijing 100190, China.
authors.forename: Junya
authors.initials: J
authors.lastname: Cao
authors.affiliation: National Key Laboratory of Biochemical Engineering and Key Laboratory of Green Process and Engineering, Institute of Processing Engineering, Chinese Academy of Sciences, Beijing 100190, China. Electronic address: chaoyang@ipe.ac.cn.
authors.forename: Chao
authors.initials: C
authors.lastname: Yang
mesh_terms: D042763:Acidithiobacillus; D001152:Arsenicals / Q000737:chemistry / Q000378:metabolism*; D001419:Bacteria / Q000378:metabolism*; D001673:Biodegradation, Environmental; D002384:Catalysis; D015386:Hazardous Substances / Q000737:chemistry / Q000378:metabolism*; D010084:Oxidation-Reduction; D012834:Silver / Q000737:chemistry*; D013440:Sulfides / Q000737:chemistry / Q000378:metabolism*
chemical_list: D001152:Arsenicals; D015386:Hazardous Substances; D013440:Sulfides; D012834:Silver; C045816:arsenic trisulfide
keywords: Acidithiobacillus ferrooxidans; Ag(+); Bioleaching; Orpiment; Sulfobacillus sibiricus