摘要
从pH值、温度及吸附动力学等方面比较研究游离和经海藻酸固定化的微藻Synechococcus sp.细胞生物吸附剂对Cr（VI）的吸附性能. 研究结果表明： 游离细胞吸附剂在较宽的pH值（1～12）范围内稳定, 其表面电位等电点为pH=3;在等电点前（pH〈3）细胞对Cr（VI）吸附明显增强;在等电点后（pH＞3）细胞对Cr（VI）也表现出一定的吸附. 这表明Cr（VI）主要通过静电吸附到细胞上, 吸附的作用点为蛋白质表面的质子化氨基. 游离细胞经海藻酸固定化后, 其表面电位等电点移至pH=2, 但两者的吸附行为相似, 且都与在海藻酸钙上的吸附行为显著不同, 说明固定化细胞对Cr（VI）的吸附主要是游离微藻细胞的作用;Cr（VI）在游离和固定化细胞上的吸附是一个快速的过程, 在其质量浓度低于1 g/L的范围内符合Freundlich吸附等温方程, 在10～50 ℃吸附不受温度影响.
The biosorption of Cr（Ⅵ） on free and alginate-immobilized cells of cyanobacteria Synechococcus sp. was comparatively studied in different cases including the influence of pH value, temperature and the absorption kinetics as well as biosorption equation. The results show that free cells are stable in the range of pH 1 -12 and the surface potential isoelectric point is pH=3, and at pH value lower than potential isoelectric point, the cells adsorb fast Cr（Ⅵ）. At the pH value higher than potential isoelectric point, cells also can adsorb Cr（Ⅵ）, indicating the Cr（Ⅵ） is adsorbed basically by electrostatic force to the protonated amino groups on the surface of cells. The adsorption of Cr（Ⅵ） on the immobilized cells that have a potential isoelectric point of pH= 2, is very different from that of alginate but similar to that of the free cells, indicating the adsorption of the immobilized cells is basically due to the adsorption of the free microalgal cells. The absorption processes of Cr（Ⅵ） on both the free and immobilized cells are very fast and independent from the temperature in the range of 10 -50℃, and can be described well by Freundlich isotherm equation when the initial concentration of Cr（Ⅵ） is lower than 1 g/L.
出处
《中南大学学报（自然科学版）》
EI
CAS
CSCD
北大核心
2006年第2期241-246,共6页
Journal of Central South University:Science and Technology
基金
国家自然科学基金资助项目(50321402)
