Objective To investigate the relationship between copper speciation and microbial features （microbial communities and copper tolerance level） in order to determine the adverse effect of different forms of Cu on micr...Objective To investigate the relationship between copper speciation and microbial features （microbial communities and copper tolerance level） in order to determine the adverse effect of different forms of Cu on microorganisms. Methods Tessier＇s sequential extraction procedure was used to qualify the different Cu forms （exchangeable, carbonate bound, Fe/Mn oxide bound, residue and organic matter bound）, and the copper tolerance level （expressed as IC50, influence concentration） was measured by the plate-count method. Results By simple correlation analysis, the ICs0 was positively correlated with the concentration of exchangeable Cu （R2=0.8204）, while weakly correlated with other forms of Cu. Conclusion The bacterial community tolerance increases in the copper-contaminated soil while sensitive bacteria decrease in the copper-contaminated soils. The exchangeable Cu exerts high toxicity to microbial communities.展开更多
This paper elaborated on the sustainability of the copper extraction process. In fact, an alternative copper extraction route from mixed sulphide ores, chalcopyrite and chalcocite using mesophilic biomass consortium a...This paper elaborated on the sustainability of the copper extraction process. In fact, an alternative copper extraction route from mixed sulphide ores, chalcopyrite and chalcocite using mesophilic biomass consortium at 33.3 °C and ferric leaching process were attempted. Bioleaching experiments were settled with a fraction size of-75+53 μm. Bacteria were used as the catalyst. A copper yield of 65.50% was obtained. On the other hand, in ferric leaching process, with a fraction size of-53+38 μm, when the temperature was increased to 70 °C, the copper leaching rate increased to 78.52%. Thus, comparatively, the mesophilic bioleaching process showed a more obvious advantage in copper extraction than leaching process with a high temperature. However, it has been resolved from the characterization performed using SEM-EDS, FTIR and XRD observations coupled with different thermodynamic approaches that, the indirect mechanism is the main leaching mechanism, with three transitory mechanisms(polysulphide, thiosulphate and elemental sulphur mechanisms) for the mixed chalcopyrite-chalcocite ore. Meanwhile, the speciation turns into Cu2 S-Cu S-Cu5 Fe S4-Cu2 S before turning into Cu SO4. While ferrous oxidation and the formation of ferric sulphate occur, and there is a formation of strong acid as bacteria digest sulphide minerals into copper sulphate at low temperature, which is why this copper production scenario requires a redox potential more than 550 m V at room temperature for high copper leaching rate.展开更多
基金This research was funded by International Copper Association with contract Number: E-AS-04-02.
文摘Objective To investigate the relationship between copper speciation and microbial features （microbial communities and copper tolerance level） in order to determine the adverse effect of different forms of Cu on microorganisms. Methods Tessier＇s sequential extraction procedure was used to qualify the different Cu forms （exchangeable, carbonate bound, Fe/Mn oxide bound, residue and organic matter bound）, and the copper tolerance level （expressed as IC50, influence concentration） was measured by the plate-count method. Results By simple correlation analysis, the ICs0 was positively correlated with the concentration of exchangeable Cu （R2=0.8204）, while weakly correlated with other forms of Cu. Conclusion The bacterial community tolerance increases in the copper-contaminated soil while sensitive bacteria decrease in the copper-contaminated soils. The exchangeable Cu exerts high toxicity to microbial communities.
文摘This paper elaborated on the sustainability of the copper extraction process. In fact, an alternative copper extraction route from mixed sulphide ores, chalcopyrite and chalcocite using mesophilic biomass consortium at 33.3 °C and ferric leaching process were attempted. Bioleaching experiments were settled with a fraction size of-75+53 μm. Bacteria were used as the catalyst. A copper yield of 65.50% was obtained. On the other hand, in ferric leaching process, with a fraction size of-53+38 μm, when the temperature was increased to 70 °C, the copper leaching rate increased to 78.52%. Thus, comparatively, the mesophilic bioleaching process showed a more obvious advantage in copper extraction than leaching process with a high temperature. However, it has been resolved from the characterization performed using SEM-EDS, FTIR and XRD observations coupled with different thermodynamic approaches that, the indirect mechanism is the main leaching mechanism, with three transitory mechanisms(polysulphide, thiosulphate and elemental sulphur mechanisms) for the mixed chalcopyrite-chalcocite ore. Meanwhile, the speciation turns into Cu2 S-Cu S-Cu5 Fe S4-Cu2 S before turning into Cu SO4. While ferrous oxidation and the formation of ferric sulphate occur, and there is a formation of strong acid as bacteria digest sulphide minerals into copper sulphate at low temperature, which is why this copper production scenario requires a redox potential more than 550 m V at room temperature for high copper leaching rate.
