酿酒酵母对放射性核素铯的生物吸附

Biosorption of Cesium by Saccharomyces cerevisia

实验研究金属Cs+在酿酒酵母上的生物吸附特性,包括生物吸附动力学、吸附平衡、吸附等温线以及菌体吸附Cs+前后红外光谱的变化。实验结果表明,Cs+在酿酒酵母上的生物吸附可分为两个阶段,第一阶段为物理吸附,在20 min内达到平衡。Cs+在酵母上的吸附过程可很好地用准二级动力学方程来描述(R2=0.989),平衡吸附量qe为7.18 mg/g,动力学参数k2为3.56×10-3g/(mg.min)。Cs+在酿酒酵母上的生物吸附可用Langmuir和Freundlich方程来描述,最大吸附量qmax为10.13 mg/g。酿酒酵母吸附Cs+后,红外光谱峰形基本保持不变。可见,吸附过程未破坏吸附剂的结构,但某些吸收峰发生了漂移。

The characteristics of Cs^＋ biosorption by Saccharomyces cerevisia was investi-gated, including the biosorption kinetics, biosorption equilibrium, isotherm as well as the IR spectrum of biomass pre-and post-biosorption. The experimental results show that the process of Cs^＋ biosorption onto the biomass of Saccharomyces cerevisia can be devided into two stages, the first stage is physical sorption and the sorption equilibrium is very quickly reached （within 20 min）. The biosorpdon kinetics can be described by the pseudo second-order equation quite well （R^2=0.989）, the kinetic parameters k2 and qe are 3.56×10^-3 g/（mg.min） and 7.18 mg/g, respectively. The equilibrium isotherm data can be fitted with Langmuir and Freundlich models, with the maximum biosorptive capacity of 10.13 mg/g. Both the IR spectra of the biomass pre-and post-biosorption almost are same, and it indicates that the biosorption of Cs^＋ does not change the struc-ture of the biomass, however, some adsorptive peaks shift.