固定化菌体吸附矿山废水中重金属的研究

Biosorption of heavy metals from mine wastewater by immobilized bacteria

研究了固定化菌体对矿山废水重金属的吸附性能.结果表明,固定化菌体对重金属有良好的富集性能,投加15g·L-1的固定化菌体,对100mg·L-1Cu、50mg·L-1Zn的去除率分别可达94.4%、80.6%.废水pH、菌体投加量对固定化菌体的处理效果影响较大,其最佳值分别为3·5、15g·L-1.经4轮吸附-解吸循环实验,显示固定化菌体可重复利用3次,固定化菌体在使用第3次时,对100mg·L-1Cu、50mg·L-1Zn的去除率分别为67.4%、46.5%.用固定化菌体的流化床工艺处理废水最佳参数为曝气量4.02L·min-1,处理2h.用固定化菌体的流化床工艺处理矿山废水取得了较好的效果,对于浓度低于10mg·L-1的重金属,去除率达到了100%,对浓度为579.2mg·L-1Fe的去除率也达到了56·6%,表明该工艺具有较好的工业化前景.

The utility of immobilized bacteria as a biosorbent for heavy metals from mine wastewater was investigated. The experimental results showed that heavy metals could be efficiently accumulated by the immobilized bacteria with removal efficiencies of 94.4% and 80.6% for 100 mg·L^-1 Cu and 50 mg·L^-1 Zn, respectively, at a strain dose of 15 mg·L^-1. The biosorption efficiency was strongly influenced by the pH of the mine wastewater （ optimal pH 3.5 ） and strain dose （ optimal value 15 mg·L^-1 ）. Immobilized bacteria regeneration studies were carried out over four sorption-desorption cycles. Removal efficiencies of 67.4% and 46.5 % for 100 mg·L^-1 Cu and 50 mg·L^-1 Zn were still attained in the third cycle. An immobilized bacteria based fluldized bed technique was developed to handle the mine wastewater. Optimal operation conditions for the fiuidized bed were 4.02 L· min^-1 aeration and 2 h treatment time. The immobilized bacteria fiuidized bed effectively treated mine wastewater, removing 100% of all heavy metals with concentrations lower than 10 mg·L^-1 and 56.6% of Fe, initially present at 579.2 mg·L^-1, thus this process is a promising technique for future applications.