Effects of 4-nonylphenol on iron (Ⅱ) oxidation by Sulfobacillus thermosulfidooxidans
In heap leach-solvent extraction-electrowinning operations, solvent extraction reagents entrained in the aqueous phase are fed to the top of a heap from where they percolate through the bed and encounter bioleaching microorganisms. 4-Nonylphenol (4-NP) is a minor constituent of the copper extractant LIX984N used widely in copper hydrometallurgy to recover copper from aqueous leach liquors. The purpose of this study was to examine the inhibitory effects of 4-NP on growth and iron (Ⅱ) oxidation by Sulfobacillus thermosulfidooxidans, a moderately thermophilic acidophilic bacterium frequently found in sulfide heap leaching systems. For this species inhibition of iron(Ⅱ) oxidation manifested itself in three ways, the most diagnostic of which were the significantly increased and variable lag times combined with an unpredictable failure to oxidise iron (Ⅱ) at 4-NP concentrations near a critical limit of 2 mg/L. These effects were consistent with a hypothesis that 4-NP had caused the large majority of cells to become inactive in respect of iron (Ⅱ) oxidation and cell replication, leaving only a low concentration of cells capable of growth. However, ancillary tests showed that the link between cell replication and iron(Ⅱ) oxidation had been broken. It is thought that this separation of physiological activities that are normally linked in bioleaching acidophiles would allow the bacteria to obtain the necessary energy to maintain cell homeostasis in an inhospitable environment. Entrainment of SX reagents in general and 4-NP in particular into the solutions applied to sulfide heaps may impact on the species composition and the long-term viability of the microbial community, depending on the sensitivities of individual species to the organic compounds. However, as long as iron(Ⅱ) biooxidation to iron (Ⅲ) occurs even at reduced rates, metal extraction from exposed sulfide grains can occur.
4-nonylphenol Sulfobacillus ferrous oxidation toxicity
David Collinson Denis Shiers Helen Watling
A. J. Parker Cooperative Research Centre for Integrated Hydrometallurgy Solutions,CSIRO Minerals Down Under Flagship, CSIRO Process Science and Engineering,PO Box 7229, Karawara, 6152, Western Australia, Australia
国际会议
The 19th International Biohydrometallurgy Symposium(第19届国际生物湿法冶金大会 IBS2011)
长沙
英文
258-265
2011-09-18（万方平台首次上网日期，不代表论文的发表时间）