蛋白核小球藻对铅、镉和汞吸附速率及其影响因素的研究

Biosorption Rate and Influence Factors of Pb^(2+),Cd^(2+) and Hg^(2+) by Chlorella pyrenoidosa

通过吸附时间、藻细胞密度和重金属浓度等参数条件的变化,研究蛋白核小球藻(Chlorella pyrenoidosa)对海水中Pb2+、Cd2+和Hg2+的吸附。结果表明,蛋白核小球藻对Pb2+、Cd2+和Hg2+的吸附率分别在2～4d内快速升高后趋于平衡,而吸附量在第1d达到最大值后逐渐变小。藻细胞密度为1×106cell·mL-1时,吸附量最大,当藻细胞密度达到4×106cell·mL-1时,吸附率增幅减小并趋于平衡。随着Pb2+、Cd2+和Hg2+浓度升高,吸附率呈逐渐变小趋势,吸附量却增加。蛋白核小球藻吸附Pb2+符合Freundlich等温线方程,而吸附Cd2+和Hg2+符合Dubimim-Radushkevich等温线方程。蛋白核小球藻对Pb2+、Cd2+和Hg2+的最大吸附量分别为4.84、37.7mg·L-1和5.61μg·L-1,吸附能力顺序为Cd2+>Pb2+>Hg2+。

At present,heavy metals contamination has become a worldwide focus on concerning for the levels of pollution and its obvious impact on human health.In this paper,the biosorption of Pb2＋,Cd2＋ and Hg2＋ by Chlorella pyrenoidosa in seawater under different adsorption time,the cell density of algal and the concentrations of heavy metals were investigated,and the adsorption isotherm model was established to provide basic data for the biological treatment of heavy metal wastewater by algae.The results showed as follows：the adsorption rate of Pb2＋、Cd2＋ and Hg2＋ by C.pyrenoidosa increased rapidly in 2~4 days and then tended to balance,the amount of heavy metals adsorption reached the maximum at the first day and then decreased gradually.The amount of heavy metals adsorption reached the maximum at the algal cell density of 1×106 cell·mL-1,the adsorption rate tended to balance at the algal cell density of 4×106 cell·mL-1.With the concentrations of Pb2＋、Cd2＋ and Hg2＋ increasing,the adsorption rate showed a trend of gradually descent while the amount of heavy metals adsorption increased.The adsorption pattern of Pb2＋ by C.pyrenoidosa was more in accordance with Freundlich isotherm equation,and the adsorption patterns of Cd2＋ and Hg2＋ were more in accordance with Dubimim-Radushkevich isotherm equation.The maximum amount of adsorption of Pb2＋、Cd2＋ and Hg2＋ were 4.84 mg·L-1,37.7 mg·L-1,5.61 μg·L-1,respectively,and the order of adsorption capacity was Cd2＋Pb2＋Hg2＋.