水华束丝藻和铜绿微囊藻对水中甲基汞的吸附特征及动力学研究

Study on Adsorption Characteristics and Kinetics of Methylmercury in Water by Aphanizomenon flosaquae and Microcystis aeruginosa

本文探究了活、死水华束丝藻和铜绿微囊藻对水中甲基汞(MeHg)的吸附动力学特征和等温吸附模型。结果表明,当MeHg浓度为100 ng/L时,活、死水华束丝藻能吸附水中99.2%和90.9%的MeHg,平衡吸附量分别为9.9×10^-2ng/(10^8cells)和9.1×10^-2ng/(10^8cells),活、死铜绿微囊藻能吸附水中98.5%和94.0%的MeHg,平衡吸附量分别为9.9×10^-2ng/(10^8cells)和9.4×10^-2ng/(10^8cells);两种藻对MeHg的吸附过程符合准一级、准二级动力学模型;活水华束丝藻和活、死铜绿微囊藻对MeHg的等温吸附过程符合Freundlich等温吸附模型,死水华束丝藻对MeHg的等温吸附过程符合Langmiur等温吸附模型;对藻细胞结构进行表征,发现活藻和死藻对MeHg的吸附在细胞表面均呈现为生物快速吸附过程,活藻还呈现为生物慢速富集过程,故活藻对MeHg的吸附率高于死藻。

The adsorption kinetics and isotherm adsorption model of methylmercury(MeHg)in water by living,dead Aphanizomenon flosaquae and Microcystis aeruginosa were studied.The results showed that when the concentration of MeHg was 100 ng/L,for living and dead Aphanizomenon flosaquae,99.2%and 90.9%of MeHg in water were adsorbed,respectively,and the respective equilibrium adsorption amounts were 9.9×10^-2 ng/(10^8 cells)and 9.1×10^-2 ng/(10^8 cells),respectively.For living and dead Microcystis aeruginosa,98.5%and 94.0%of MeHg in water were adsorbed,respectively,and the respective equilibrium adsorption amounts were 9.9×10^-2 ng/(10^8 cells)and 9.4×10^-2 ng/(10^8 cells),respectively.The adsorption kinetics of MeHg by two algae were in accordance with the quasi-first-order and quasi-second-order kinetic models.The isotherm adsorptions of MeHg by living Aphanizomenon flosaquae and living and dead Microcystis aeruginosa were in accordance with the Freundlich isotherm adsorption model.The isotherm adsorption of MeHg by dead Aphanizomenon flosaquae was in accordance with the Langmuir isotherm adsorption model.The structure of algae cell was characterized and indicated that the adsorption of MeHg by living algae and dead algae showed a rapid biological adsorption process on the cell surface,while the living algae also showed a slow biological enrichment process,so the adsorption rate of MeHg by living algae was higher than that of dead algae.