关键词: 菹草, 重金属, 伪二级动力学方程, Freundlich吸附等温线, 去除率, 富集

Abstract: Experiments were conducted to study the biosorption properties of heavy metals (copper，lead and zinc) by Potamogeton crispus which flourishes in winter and spring at relatively low temperature(10℃).Removal ratio of heavy metals in water with different initial heavy metal concentrations by P.crispus was studied as well. We also studied heavy metal bioaccumulation by different organs (leaf, stem, rhizome and root) of P.crispus. The results showed that Cu²⁺ and Zn²⁺ sorption by P.crispus reached balance within 20 min whereas Pb²⁺ sorption reached balance within 50 min. The results of sorption kinetics conformed to the pseudo second order kinetics equation with correlativity coefficient reaching 1, 1, 0.997 8, respectively. Freundlich sorption isotherm was well fit for Cu²⁺, Pb²⁺, Zn²⁺ sorption process by P.crispus. Sorption capability for Cu²⁺, Pb²⁺, Zn²⁺ were 66.900 6, 26.543 0, 30.371 8 mg·L^-1, respectively. In the desorption test, the desorption ratios of all Cu²⁺， Pb²⁺，Zn²⁺ initial concentration were nearly zero. Removal ratio of heavy metals from water was high after planting P.crispus. With the initial heavy metal concentration increased, removal ratio of Cu²⁺ and Pb²⁺ firstly declinced and then increased whereas removal ratio of Zn²⁺ was gradually increased. Bioaccumulation capability of different organs was distinguishing. Bioaccumulation capability was Cu²⁺＞Zn²⁺＞Pb²⁺. The same heavy metal content in different organs had marked difference. Leaf was the main heavy metal bioaccumulation organ. The initial heavy metal concentration of water may affect heavy metal bioaccumulation capability of every organ. Generally, with increasing initial heavy metal concentration, content of heavy metals in organs increased differently but bioaccumulation concentration of organs of P.crispus decreased.

Key words: Potamogeton crispus L., heavy metal, pseudo second order kinetics equation, Freundlich sorption isotherm, removal ratio, bioaccumulation