The changes of pH,redox potential,concentrations of soluble iron ions and Cu^2＋ with the time of bioleaching chalcopyrite concentrates by acidithiobacillus ferrooxidans were investigated under the different condition...The changes of pH,redox potential,concentrations of soluble iron ions and Cu^2＋ with the time of bioleaching chalcopyrite concentrates by acidithiobacillus ferrooxidans were investigated under the different conditions of initial total-iron amount as well as mole ratio of Fe（III） to Fe（II） in the solutions containing synthetic extracellular polymeric substances （EPS）.When the solution potential is lower than 650 mV （vs SHE）,the inhibition of jarosites to bioleaching chalcopyrite is not vital as EPS produced by bacteria can retard the contamination through flocculating jarosites even if concentration of Fe（III） ions is up to 20 g/L but increases with increasing the concentration of Fe（III） ions;jarosites formed by bio-oxidized Fe3＋ ions are more easy to adhere to outside surface of EPS space on chalcopyrite;the EPS layer with jarosites acts as a weak diffusion barrier to further rapidly create a high redox potential of more than 650 mV by bio-oxidizing Fe^2＋ ions inside and outside EPS space into Fe^3＋ ions,resulting in a rapid deterioration of ion diffusion performance of the EPS layer to inhibit bioleaching chalcopyrite severely and irreversibly.展开更多
Ethylthionocarbamates （ETC）, which is the most widely used as collectors in the flotation of sulfide, is known to cause serious pollution to soil and groundwater. The potential biodegradation of ETC was evaluated b...Ethylthionocarbamates （ETC）, which is the most widely used as collectors in the flotation of sulfide, is known to cause serious pollution to soil and groundwater. The potential biodegradation of ETC was evaluated by applying a mixed culture of iron-reducing bacteria （IRB） enriched from tailings dam sediments. The results showed that ETC can be degraded by IRB coupled to Fe（III） reduction, both of which can be increased in the presence of anthraquinone-2,6-disulfonate （AQDS）. Moreover, Fe（III）-EDTA was found to be a more favorable terminal electron acceptor compared to α-Fe2O3, e.g., within 30 d, 72% of ETC was degraded when α-Fe2O3＋AQDS was applied, while it is 82.67% when Fe（III）-EDTA＋AQDS is added. The dynamic models indicated that the kETC degradation was decreased in the order of Fe（III）-EDTA＋AQDS〉α-Fe2O3＋AQDS〉Fe（III）-EDTA〉α-Fe2O3, with the corresponding maximum biodegradation rates being 2.6, 2.45, 2.4 and 2.0 mg/（L·d）, respectively, and positive parallel correlations could be observed between kFe（III） and kETC. These findings demonstrate that IRB has a good application prospect in flotation wastewater.展开更多
We investigated the reduction of lepidocrocite(γ-FeOOH) by Shewanella oneidensis MR-1 in the presence and absence of Cd. The results showed that Cd^(2+) retarded microbial reduction of γ-Fe OOH and avoided formation...We investigated the reduction of lepidocrocite(γ-FeOOH) by Shewanella oneidensis MR-1 in the presence and absence of Cd. The results showed that Cd^(2+) retarded microbial reduction of γ-Fe OOH and avoided formation of magnetite. The inhibitory effect on γ-Fe OOH transformation may not result from Cd^(2+) toxicity to the bacterium; it rather was probably due to competitive adsorption between Cd^(2+) and Fe^(2+) on γ-Fe OOH as its surface reduction catalyzed by adsorbed Fe^(2+) was eliminated by adsorption of Cd^(2+).展开更多
基金Project(2010CB630904) supported by the National Basic Research Program of ChinaProject(50621063) supported by the Chinese Science Foundation for Distinguished Group
文摘The changes of pH,redox potential,concentrations of soluble iron ions and Cu^2＋ with the time of bioleaching chalcopyrite concentrates by acidithiobacillus ferrooxidans were investigated under the different conditions of initial total-iron amount as well as mole ratio of Fe（III） to Fe（II） in the solutions containing synthetic extracellular polymeric substances （EPS）.When the solution potential is lower than 650 mV （vs SHE）,the inhibition of jarosites to bioleaching chalcopyrite is not vital as EPS produced by bacteria can retard the contamination through flocculating jarosites even if concentration of Fe（III） ions is up to 20 g/L but increases with increasing the concentration of Fe（III） ions;jarosites formed by bio-oxidized Fe3＋ ions are more easy to adhere to outside surface of EPS space on chalcopyrite;the EPS layer with jarosites acts as a weak diffusion barrier to further rapidly create a high redox potential of more than 650 mV by bio-oxidizing Fe^2＋ ions inside and outside EPS space into Fe^3＋ ions,resulting in a rapid deterioration of ion diffusion performance of the EPS layer to inhibit bioleaching chalcopyrite severely and irreversibly.
基金Project(51708561)supported by the National Natural Science Foundation of ChinaProjects(CZP17097,CZW15037)supported by the Fundamental Research Funds for the Central Universities,China
文摘Ethylthionocarbamates （ETC）, which is the most widely used as collectors in the flotation of sulfide, is known to cause serious pollution to soil and groundwater. The potential biodegradation of ETC was evaluated by applying a mixed culture of iron-reducing bacteria （IRB） enriched from tailings dam sediments. The results showed that ETC can be degraded by IRB coupled to Fe（III） reduction, both of which can be increased in the presence of anthraquinone-2,6-disulfonate （AQDS）. Moreover, Fe（III）-EDTA was found to be a more favorable terminal electron acceptor compared to α-Fe2O3, e.g., within 30 d, 72% of ETC was degraded when α-Fe2O3＋AQDS was applied, while it is 82.67% when Fe（III）-EDTA＋AQDS is added. The dynamic models indicated that the kETC degradation was decreased in the order of Fe（III）-EDTA＋AQDS〉α-Fe2O3＋AQDS〉Fe（III）-EDTA〉α-Fe2O3, with the corresponding maximum biodegradation rates being 2.6, 2.45, 2.4 and 2.0 mg/（L·d）, respectively, and positive parallel correlations could be observed between kFe（III） and kETC. These findings demonstrate that IRB has a good application prospect in flotation wastewater.
基金financially supported by the National Natural Science Foundation of China(41601239)the Highlevel Leading Talent Introduction Program of GDAS,the China Postdoctoral Science Foundation(2016M600644)the"Pearl River Talents"Postdoctoral Program of Guangdong Province,and the National Key Research and Development Program of China(2016YFD0800703)
文摘We investigated the reduction of lepidocrocite(γ-FeOOH) by Shewanella oneidensis MR-1 in the presence and absence of Cd. The results showed that Cd^(2+) retarded microbial reduction of γ-Fe OOH and avoided formation of magnetite. The inhibitory effect on γ-Fe OOH transformation may not result from Cd^(2+) toxicity to the bacterium; it rather was probably due to competitive adsorption between Cd^(2+) and Fe^(2+) on γ-Fe OOH as its surface reduction catalyzed by adsorbed Fe^(2+) was eliminated by adsorption of Cd^(2+).
