有菌和无菌体系下磁黄铁矿氧化的电化学研究

Electrochemistry of oxidation of pyrrhotite in presence and absence of Acidthiobacillus ferrooxidans

在有菌和无菌酸性体系下,对磁黄铁矿电化学氧化进行研究。研究结果表明:在磁黄铁矿被氧化过程中伴随元素S的生成,覆盖于电极表面,使电极表面发生钝化;随着电位的升高,元素S被氧化成SO42-,钝化膜被"击穿";氧化亚铁硫杆菌作用后增强了磁黄铁矿的反应性能,促进了磁黄铁矿氧化反应速度,腐蚀反应速度明显提高,但细菌对磁黄铁矿电极的氧化还原反应过程机理并没有产生影响;在相同电位下,有细菌时的阻抗明显低于无细菌时的阻抗,细菌的存在加速了表面物质的扩散,电极过程受电化学步骤控制,测定结果与线性扫描所得结果一致。

The electrochemical research of pyrrhotite in the presence and absence of Acidthiobacillus ferrooxidans in acidic growth media was investigated.The results show that elemental sulfur is the major secondary mineral formed during oxidation of pyrrhotite,which covers on the electrode and makes the electrode passive;then sulphur is oxidized into sulphate and passive film breakdown with the increase of potential.The reactive nature of pyrrhotite is enhanced when Acidthiobacillus ferrooxidans is in the solution,and the reactive nature of pyrrhotite is enhanced,and the rate of pyrrhotite oxidation as well as the corrosion rate increases.However,Acidthiobacillus ferrooxidans don＇t affect the reaction mechanism of pyrrhotite of anode process.The impedances in the presence of Acidthiobacillus ferrooxidans are obviously lower than that in the absence of Acidthiobacillus ferrooxidans.Because of the presence of bacteria,the diffusion velocity of surface materials can be accelerated very much,with the electrode process controlled by electrochemical steps.The proposed reaction results confirm those obtained in liner polarization satisfactorily.