从铅锌矿渣中分离的微生物对重金属吸附特性的研究

Absorption of Heavy Metals by Microorganisms Isolated from Lead-zinc Tailing

从铅锌矿渣中分离到 16种菌 (包括 7株细菌和 9株真菌 ) ,并研究了它们对Zn2 + ,Pb2 + ,Cu2 + 的吸附特性。发现大多数菌株对Pb2 + 与Zn2 + 有不同程度的吸附 ,但对Cu2 + 的吸附能力较小。菌株对Zn2 + 的吸附率大于对Pb2 + 的吸附 ,能吸附Pb2 + 的菌株也能吸附Zn2 + 。pH 4～ 6是真菌吸附金属离子的较好范围 ,细菌仅在pH =5 .0条件下 ,对Pb2 + 与Zn2 + 有吸附。在测试的不同金属离子浓度范围内 (5 0mg/L <Pb2 + <70 0mg/L ,2 0mg/L <Zn2 + <32 0mg/L) ,真菌对Pb2 + ,Zn2 + 的吸附率随离子浓度的增加而增加 ,但细菌仅在一定的浓度值以下 (Pb2 + <10 0mg/L ,Zn2 + <80mg/L)表现吸附率增加。真菌 2个菌株的吸附率随时间变化的规律表明 ,菌株对金属离子的吸附符合“吸附 +细胞膜传输”模型。

High absorption ability of lead, zinc and copper by 7 strains of bacteria and 9 strains of fungi isolated from lead-zinc tailing was characterized. It showed that most of these microorganisms have absorption ability of Pb{2} and Zn{2}, and relatively more Zn{2} could be absorbed than Pb{2}. On the other hand, only a few of strains could absorb Cu{2} with low ability. Strains with excellent absorption of Pb{2} and Zn{2} were selected to test their absorption ability at different pH and different concentrations of Pb{2} and Zn{2}. The results showed that, for fungi, the most optimistic pH for absorption is 4～6, but for bacteria the optimrstic is 5.0. The absorption ability of fungi was enhanced by increased concentration of metals (50mg/L<Pb{2}<700mg/L,20mg/L<Zn{2}<320mg/L), and bacteria also showed the same response under a lower concentration of metals (Pb{2}<100mg/L,Zn{2}<80mg/L). The absorption changes to the absorption time demonstrated that, absorption of Zn{2} and Pb{2} ions occurred in two processes: rapid absorption on cells surface and slow transportation into cells.;