摘要
为了深入探讨酿酒酵母吸附贵金属离子Ag+的特性,研究了吸附时间、离子浓度、初始pH值、温度对废弃酿酒酵母吸附Ag+的影响,并分析了动力学、热力学以及等温吸附特性.结果表明,酵母吸附Ag+的过程进行得很快,当Ag+初始浓度为1mmol.L-1、细胞浓度2 g.L-1条件下,反应10 min,Ag+可以达到平衡吸附量的86%以上.随后在24 h内吸附量缓慢增加,去除率基本维持在51%~55%左右.酵母吸附Ag+的过程可以用准一级和准二级动力学方程描述,后者模拟效果更好.酵母吸附Ag+的等温吸附过程可以用Langmuir方程描述,但Freundlich方程拟合效果较差.当Ag+初始浓度为0~8 mmol.L-1、酵母浓度2g.L-1条件下,酵母吸附Ag+的Langmuir理论饱和生物吸附容量为0.385 mmol.g-1.在pH 2.0~7.2范围内,吸附量随着溶液初始pH值升高而升高.10~40℃范围内,温度对酵母吸附Ag+的影响不如pH值的影响显著,特别是在低离子浓度下尤其如此.酵母吸附Ag+的较适宜温度为20~30℃.热力学分析表明,酵母吸附Ag+具有自发性、熵增特征.
To understand the characteristics of Ag^＋ biosorption by the waste biomass of Saccharomyces cerevisiae, the effect of environmental factors on metal biosorption were studied, including sorption time, initial concentration of metal ions, temperature, initial pH value, ionic strength. The relevant kinetics, equilibrium and thermodynamics were discussed. The results showed that biosorption of Ag^＋ on the biomass were very rapid processes. Ag^＋ uptake quantity within 10 min arrived at 86% of that of the equilibrium uptake during 24 h uptake when initial concentration of Ag^＋ was 1 mmol·L^-1 and the biomass concentration was 2 g·L^-1 Ag^＋ uptake process followed the pseudo-first and the pseudo-second order kinetics. The pseudo-second order kinetic gave better fitting results than the pseudo-first order kinetic. The equilibrium data could be fitted well with the Langmnir model, better than the Freundlich model. The maximum sorption capacity obtained from the Langmuir model was 0.385mmol·L^-1 when initial Ag^＋ concentration was 0-8 mmol·L^-1 and the biomass concentration of 2 g·L^-1 . The values of the thermodynamic constants of biosorption were calculated and demonstrated that the biosorption process of Ag^＋ was spontaneous and the entropy increased. The biosorption process by the waste yeast was favorable for the removal and recovery of Ag^＋ from wastewater.
出处
《环境科学》
EI
CAS
CSCD
北大核心
2008年第11期3200-3205,共6页
Environmental Science
基金
国家自然科学基金项目(50278045)
清华大学基础研究基金项目(JC2002054)
