铜绿假单胞菌对铜和铅的吸附

Study of the biosorption of copper and lead by Pseudomonas aeruginosa

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.

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