耐盐鲁氏酵母(Zygsoaccharomyces rouxii)CICC1379吸附水中重金属Cu^(2+)研究

Biosorption of Cu^(2+) from aqueous solution by salt-tolerant yeast Zygosaccharomyces rouxii CICC1379

为了研究耐盐鲁氏酵母(Zygosaccharomyces rouxii)CICC1379细胞冻干粉对重金属Cu2+的吸附作用及机理,对影响该酵母脱除水中Cu2+的主要因素(温度、初始pH和吸附时间等)进行了探讨,并对Cu2+的吸附动力学和吸附模型进行了研究.结果表明,温度(25～40℃)对耐盐鲁氏酵母粉吸附Cu2+的影响不大;初始pH(2～7)对Cu2+脱除率影响较大,最适pH值在4～6之间,而pH=2时的吸附效果较差.经耐盐鲁氏酵母处理后,溶液pH发生了变化,基本维持在4.00～6.99之间,且均趋向于相同质量氯化铜溶于水后的自然pH值(5.2).耐盐鲁氏酵母粉在5min内对Cu2+的吸附量可达到其最大吸附量的89.2%,30min可达到吸附平衡,其吸附动力学适合采用准二级动力学方程描述.与Langmuir方程相比,耐盐鲁氏酵母对Cu2+的吸附过程更适合采用Freundlich方程描述.

We studied the biosorption process and mechanism of Cu2＋ from aqueous solution onto lyophilized biomass of salt-tolerant Zygosaccharomyces rouxii CICC1379. The effects of temperature,initial pH and contact time on the rate of removal of Cu2＋ from aqueous solution were measured in a batch system. The biosorption kinetics and isotherm models were also studied. The results showed that temperature （25~40℃） had an insignificant effect on Cu2＋ biosorption onto the biomass,while initial pH affected the Cu2＋ removal rate significantly. The optimum initial pH for the biosorption was 4~6 and decreased as the pH dropped to 2. During the treatment process,the pH of the solution changed from an initial pH range of 4.00 to 6.99 to the natural pH of CuCl2 with the same concentration. The 89.2% of its maximum Cu2＋ biosorption capability was achieved during the first 5 min and the Cu2＋ biosorption equilibrium was attained within 30 min. The kinetics data fit well with the pseudo-second-order equation. The Freundlich isotherm model described the experimental data of the biosorption of Cu2＋ onto Z. rouxii CICC1379 biomass perfectly,followed by the Langmuir isotherm model.