脱硫弧菌SRB7对重金属铬Cr(VI)的还原特性

Characteristics of Reduce Cr(VI) by Desulfovibrio SRB7

摘要:

利用化工厂污泥废水中分离到的一株耐酸脱硫弧菌(Desulfovibrio SRB7), 对不同pH、温度、碳源、菌废比等条件下SRB7还原Cr(VI)能力进行研究。并从H2S还原途径、电子传递途径以及胞外聚合物(EPS)吸附途径研究SRB7菌体整体去除Cr(VI)的特性。结果表明: 当Cr(VI)起始浓度为50 mg/L时, pH 7.5, 培养温度36°C, 碳源为乳酸钠, 混合菌液和Cr(VI)溶液的菌废比为1:5(V/V)能获得很好的还原效果。在SRB7去除Cr(VI)的特性中, 吸附途径对Cr(VI)的去除几乎不起作用; 电子传递途径在Cr(VI)的还原过程中不占优势, 24 h去除率为51.42%; 而H2S途径在Cr(VI)的还原过程中占主导地位, 24 h去除率为78.02%。

Abstract:

Pollution of heavy metal chromium Cr(VI) in environment would cause cancer. Chromium Cr(VI) was defined as one of 129 important pollutants by American EPA. This study was carried out on the conditions of removal Cr(VI) including different originated pH, temperature, carbon source and the volume ratio of bacteria to wastewater using an acidproof Desulfovibrio (SRB7) which was departed from sewage sludge effluent water of a chemical plant. Meanwhile the characteristics of reducing Cr(VI) through sulfureted hydrogen approach, electron transfer approach and adsorption approach were studied. The results showed that the conditions of removal Cr(VI) were as follows: pH 7.5, temperature 36°C, using lactate sodium as the carbon sources and the volume ratio of bacteria to wastewater at 1:5(V/V), when the influent concentration was 50 mg/L. In this study for characteristics of reducing Cr(VI) by SRB7, adsorption approach couldn’t remove Cr(VI); electron transfer approach which removed 51.42% of the Cr(VI) at 24 h, was not preponderant in the process of reduce Cr(VI); sulfureted hydrogen approach which removed 78.02% of the Cr(VI) at 24 h, was preponderant in the process of reduce Cr(VI).