微囊藻对锑(V)生物吸附作用研究

以富营养化湖泊水华暴发的主要藻种-微囊藻干物质作为生物吸附剂，考察不同生物量、初始pH值、吸附时间等因素对废水中锑（V）生物去除作用的影响，探讨微囊藻对Sb（V）的生物吸附性能；通过zeta电位和红外光谱技术揭示其吸附机理，并推断其反应方程式.结果表明：在室温条件下，吸附剂用量为0.5g：20mL，pH值为2.0，时间为1h时，Sb（V）的生物吸附达到最大容量为5.84mg/g（以干重计），吸附等温线符合Langmuir等温方程（R²=0.993），生物吸附动力学过程遵循假二级动力学模型（R²=0.994）.在pH值2.0~9.0范围内，其生物吸附效率随pH值增加逐渐下降.Zeta电位和ATR-IR光谱结果表明微囊藻细胞壁表面的氨基、羧基和羟基为Sb（V）的主要吸附位点，其中质子化的氨基通过静电吸引作用结合Sb（V），羧基和羟基则通过表面络合作用与Sb（V）结合形成内源络合物.

Studies on biosorption of antimony(V) by Microcystis

The dried biomass of dominate species of algae blooms, Microcystis, was used as a biosorbent to remove Sb(V) from effluents in this study. The biosorption characteristics of Sb (V) by Microcystis were investigated under various environmental parameters, biosorbent dosage, initial pH and contact time.The possible mechanisms were speculated based on the zeta potential and ATR-IR spectra analysis. Reaction equations between anionic Sb (V) and functional groups on the cell surface of Microcystis were inferred. The maximalbiosorption capacity was determined to be 5.84mg/g(dry weight) under biomass to solution ratio of 0.5g: 20mL, pH 2.0, equilibrium time 1h and room temperature. The biosorption isotherms were fitted well with Langmuir model (R²=0.993) and the biosorption kinetics process obeyed pseudo-secondorder rate kinetics equation (R²=0.994). The biosorption capacities of Sb (V) decreased with an increase of pH from 2.0to 9.0. The results of zeta potential and ATR-IR spectra analysis suggestthe involvement of amino, carboxyl and hydroxyl groups in Sb (V) biosorption. The protonated amine groups may bind anionic Sb (V) through electrostatic attraction. The protonated carboxyl groups and hydroxyl group might form an inner complex with Sb (V) through surface complexation.