Mechanism of Pyrite Dissolution in the Presence ofThiobacillus ferrooxidans
Mechanism of Pyrite Dissolution in the Presence ofThiobacillus ferrooxidans
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DOI：
10.1128/aem.65.7.2987-2993.1999
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发表时间：
1999-07
影响因子：
4.4
通讯作者：
T. Fowler;P. Holmes;F. Crundwell
中科院分区：
文献类型：
--
作者：
T. Fowler;P. Holmes;F. Crundwell
摘要尽管细菌浸出黄铁矿具有环境和商业利益，但经过35年的研究，两个核心问题仍未得到回答：氧化亚铁硫杆菌是否能提高浸出速率，使其高于相同条件下硫酸铁溶液的浸出速率，如果是，细菌如何影响这种提高？以前的研究的实验条件是这样的，铁和亚铁离子的浓度在整个实验过程中发生了很大的变化。这使得很难解释从这些以前的工作中获得的数据。这项工作的目的是回答这两个问题，采用一种实验装置，旨在保持溶液中的浓度在一个恒定的值。这是通过使用先前描述的恒定氧化还原电位装置（P. I. Harvey和F. K. Crundwell，Appl. Microbiol. 63：2586-2592，1997; T. A. Fowler和F. K. Crundwell，Appl. Microbiol. 64：3570-3575，1998）。实验在存在和不存在T.铁氧化物，在溶液中保持相同的条件。在亚铁离子和三价铁离子浓度相同的条件下，细菌对黄铁矿的溶解速率高于无细菌的黄铁矿溶解速率。浸出率对三价铁离子浓度和pH值的依赖关系的分析，以及从电化学测量获得的结果，提供了明确的证据表明，较高的浸出率与细菌是由于细菌增加的pH值在表面的黄铁矿。
ABSTRACT In spite of the environmental and commercial interests in the bacterial leaching of pyrite, two central questions have not been answered after more than 35 years of research: does Thiobacillus ferrooxidans enhance the rate of leaching above that achieved by ferric sulfate solutions under the same conditions, and if so, how do the bacteria affect such an enhancement? Experimental conditions of previous studies were such that the concentrations of ferric and ferrous ions changed substantially throughout the course of the experiments. This has made it difficult to interpret the data obtained from these previous works. The aim of this work was to answer these two questions by employing an experimental apparatus designed to maintain the concentrations in solution at a constant value. This was achieved by using the constant redox potential apparatus described previously (P. I. Harvey, and F. K. Crundwell, Appl. Environ. Microbiol. 63:2586–2592, 1997; T. A. Fowler, and F. K. Crundwell, Appl. Environ. Microbiol. 64:3570–3575, 1998). Experiments were conducted in both the presence and absence of T. ferrooxidans, maintaining the same conditions in solution. The rate of dissolution of pyrite with bacteria was higher than that without bacteria at the same concentrations of ferrous and ferric ions in solution. Analysis of the dependence of the rate of leaching on the concentration of ferric ions and on the pH, together with results obtained from electrochemical measurements, provided clear evidence that the higher rate of leaching with bacteria is due to the bacteria increasing the pH at the surface of the pyrite.