酿酒酵母生物吸附Cu^(2+)的动力学及吸附平衡研究

Kinetics and Equilibrium of Cu～(2+) Biosorption by Dried Biomass of Saccharomyces cerevisia

研究了重金属离子Cu2+在酿酒酵母上的生物吸附特性,内容包括生物吸附动力学、吸附等温线以及pH对生物吸附的影响.生物吸附动力学结果表明,当Cu2+初始浓度为71.6mg/L时,Cu2+在酿酒酵母上的生物吸附过程可以分为两个阶段,第一阶段为物理吸附,在10min内达到平衡,此后,随着时间的延长,有微量脱附现象发生.Cu2+在酵母上的吸附过程可以很好地用准二级动力学方程来描述(R2=0.9984),动力学参数k2为7.65×10-3g mg-1min-1,qe为9.15mg/g.吸附等温线结果表明,Cu2+在酿酒酵母上的生物吸附可以用Langmuir和Freundlich方程来描述,最大吸附量qmax为10.2mg/g·pH为5.0时Cu2+在酿酒酵母上的吸附量最大.酿酒酵母可用于处理低浓度含Cu2+的废水.

Biosorption is an alternative technology for treating heavy metal contaminant. The characteristics of Cu^2＋ biosorption by Saccharomyces cerevisia were investigated, including the biosorption kinetics, equilibrium isotherm and pH effect. The ex- perlment results showed that when the initial Cu^2＋ concentration was 71.6 mg/L, the process of Cu^2＋ biosorption by the dry hi- omass of S. cerevisia could be divided into two stages. The first stage was physical sorption and reached equilibrium very quick- ly （within 10 minutes ）, and then desorption took place. The biosorption kinetics could be well described by the pseudo second-order equation （R2 =0.998 4）. The kinetic parameters k2 and qe were 7. 65 × 10^-3 and 9. 15 mg/g, respectively. The equilibrium isotherm date could be fitted to the Langmuir and Freundlich models, with the largest biosorptive capacity of 10. 2 mg/g. The optimum pH for biosorption was 5. O. S. cerevisia can be applied in the treatment of the wastewater with low concentration of Cu^2＋.