铜绿假单胞菌对铜和铅的吸附

研究了铜绿假单胞菌(Pseudomonas aeruginosa)对Cu和Pb的吸附特性.结果表明,相同条件下,该菌株对Cu~(2+)的吸附率低于Pb~(2+).对于单一重金属体系,吸附率均随时间的延长先上升后平稳变化,2 h达到稳定.吸附率随投菌量的增加先迅速增加,之后趋于平稳.对于Cu~(2+),投菌量为1 g·L~(-1)时吸附率达到稳定,而Pb~(2+)的吸附效果达到平稳时的投菌量为0.5 g·L~(-1).单位质量菌体对Cu~(2+)、Pb~(2+)的吸附量随投菌量的增加而下降.pH为3时,菌体的吸附效果较差,当pH为5~8时,2种重金属的吸附效果较高.对于活菌,Pb~(2+)对菌体吸附Cu~(2+)有抑制作用,而Cu~(2+)对菌体吸附Pb~(2+)的影响无明显规律.对于失活菌,P.aeruginosa吸附Pb~(2+)和Cu~(2+)的效果均随共存重金属浓度的增大而降低,但Cu~(2+)对Pb~(2+)的影响比Pb~(2+)对Cu~(2+)的影响更显著.扫描电镜观察发现,吸附后的菌体较吸附前聚集性更好.总体而言,P.aeruginosa能对水体中共存的Cu~(2+)和Pb~(2+)有较好的吸附效果.

Study of the biosorption of copper and lead by Pseudomonas aeruginosa

The biosorption characteristics of Cu and Pb was investigated in this paper. Results reveal that the adsorption rate of Cu²⁺ was lower than Pb²⁺ under the same conditions. In the presence of only one heavy metal, adsorption rate gradually increased then stabilized after 2 h. Adsorption of heavy metal was ascended rapidly with the increase of inoculum size and then tended to stabilize at inoculum dosage of 1 g·L^-1 for Cu²⁺ and 0.5 g·L^-1 for Pb²⁺.Adsorbed amount of Cu²⁺ and Pb²⁺ by unit cell was both decreased with the increase of inoculum dosage. Cu²⁺ and Pb²⁺ adsorption rate reached maximumat pH 5~8 but lowest at pH 3. As for the living stain, adsorption of Cu²⁺was inhibited when Pb²⁺ was present, but Cu²⁺ seemed to have no significant influence on the adsorption of Pb²⁺. As for inactivation of microbes, adsorption rate of Cu²⁺ and Pb²⁺ by P. aeruginosa both decreased with the increasing concentrations of heavy metals but the influence of Cu²⁺ on Pb²⁺ adsorption was more significant than Pb²⁺ for Cu²⁺ adsorption. SEM results show that the aggregation of cells was better after adsorption. Overall, P. aeruginosa shows good adsorption performance for both Cu²⁺ and Pb²⁺.