灭活面包酵母菌对水溶液中镉离子的吸附特性

Biosorption of cadmium ions from solution by nonliving Saccharomyces cerevisiae

以灭活面包酵母菌(Saccharomyces cerevisiae)作为生物吸附剂,研究了初始液相pH值、吸附剂质量浓度ρa、Cd^(2+)初始质量浓度ρ0等因素对面包酵母菌吸附Cd^(2+)过程的影响,并进行吸附动力学、等温吸附和SEM/EDS分析.结果表明,较佳吸附条件:pH=4.5~7.0,ρa=4.0~6.0g/L,ρ0=112.4~224.8mg/L.吸附动力学分析表明面包酵母菌对Cd^(2+)的吸附是一个快速反应的过程,吸附过程可用准二级动力学模型来描述.等温吸附结果较好地符合Langmuir和Freundlich吸附模型.SEM/EDS分析发现,大量的Cd^(2+)被吸附在细胞表面,这说明灭活面包酵母菌对Cd^(2+)的吸附效果较好.

The nonliving Saccharomyces cerevisiae was utilized as biosorbent to remove Cd^（2＋）from aqueous solution.The effects of initial pH,amount of adsorbentρa,initial concentration of Cd^（2＋）ρ0on the adsorption efficiency of Cd^（2＋）were studied.Meanwhile,the adsorption kinetics,isotherm biosorption and SEM/EDS were investigated.The results indicated that the optimum condition for biosorption were as follows：pH=4.5~7.0,ρa=4.0~6.0g/L,ρ0=112.4~224.8mg/L.The analysis of adsorption kinetics showed that the biosorption of Cd^（2＋）by Saccharomyces cerevisiae was a rapid process.The biosorption process could be fitted with the pseudo-second-order kinetic model.The isotherm adsorption curve of Cd^（2＋）on baker＇s yeast accorded well with Langmuir and Freunlich model.Through SEM/EDS analysis,we can see that baker＇s yeast cell surface tends to absorb large amounts of Cd^（2＋）after being adsorbed for 1 440 minutes.As a consequence,nonliving Saccharomyces cerevisiae have a high biosorption efficiency for Cd^（2＋）.