title: Catalytic effect of light illumination on bioleaching of chalcopyrite.
abstract: The influence of visible light exposure on chalcopyrite bioleaching was investigated using Acidithiobacillus ferrooxidans. The results indicated, in both shake-flasks and aerated reactors with 8500-lux light, the dissolved Cu was 91.80% and 23.71% higher, respectively, than that in the controls without light. The catalytic effect was found to increase bioleaching to a certain limit, then plateaued as the initial chalcopyrite concentration increased from 2% to 4.5%. Thus a balanced mineral concentration is highly amenable to bioleaching via offering increased available active sites for light adsorption while eschewing mineral aggregation and screening effects. Using semiconducting chalcopyrite, the light facilitated the reduction of Fe(3+) to Fe(2+) as metabolic substrates for A.ferrooxidans, leading to better biomass, lower pH and redox potential, which are conducive to chalcopyrite leaching. The light exposure on iron redox cycling was further confirmed by chemical leaching tests using Fe(3+), which exhibited higher Fe(2+) levels in the light-induced system.
authors.affiliation: School of Minerals Processing and Bioengineering, Central South University, Changsha, China; Key Laboratory of Biohydrometallurgy, Ministry of Education, Changsha, China.
authors.forename: Shuang
authors.initials: S
authors.lastname: Zhou
authors.affiliation: School of Minerals Processing and Bioengineering, Central South University, Changsha, China; Key Laboratory of Biohydrometallurgy, Ministry of Education, Changsha, China.
authors.forename: Min
authors.initials: M
authors.lastname: Gan
authors.affiliation: School of Minerals Processing and Bioengineering, Central South University, Changsha, China; Key Laboratory of Biohydrometallurgy, Ministry of Education, Changsha, China. Electronic address: zhujy@mail.csu.edu.cn.
authors.forename: Jianyu
authors.initials: J
authors.lastname: Zhu
authors.affiliation: School of Minerals Processing and Bioengineering, Central South University, Changsha, China; Key Laboratory of Biohydrometallurgy, Ministry of Education, Changsha, China; Universität Duisburg-Essen, Biofilm Centre, Aquatische Biotechnologie, Universitätsstraße 545141 Essen, Germany.
authors.forename: Qian
authors.initials: Q
authors.lastname: Li
authors.affiliation: School of Minerals Processing and Bioengineering, Central South University, Changsha, China; Key Laboratory of Biohydrometallurgy, Ministry of Education, Changsha, China.
authors.forename: Shiqi
authors.initials: S
authors.lastname: Jie
authors.affiliation: School of Minerals Processing and Bioengineering, Central South University, Changsha, China; Key Laboratory of Biohydrometallurgy, Ministry of Education, Changsha, China.
authors.forename: Baojun
authors.initials: B
authors.lastname: Yang
authors.affiliation: School of Minerals Processing and Bioengineering, Central South University, Changsha, China; Key Laboratory of Biohydrometallurgy, Ministry of Education, Changsha, China.
authors.forename: Xueduan
authors.initials: X
authors.lastname: Liu
mesh_terms: D042763:Acidithiobacillus / Q000378:metabolism; D018533:Biomass; D002384:Catalysis; D003300:Copper / Q000737:chemistry* / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D007501:Iron / Q000737:chemistry; D008027:Light; D010084:Oxidation-Reduction; D012666:Semiconductors
chemical_list: C012819:chalcopyrite; D003300:Copper; D007501:Iron
keywords: Acidithiobacillus ferrooxidans; Bioleaching; Catalysis; Chalcopyrite; Visible light illumination