KMnO_4修饰面包酵母菌对Cd^(2+)的吸附研究  

Cd^(2+) adsorption by KMnO_4 modified baker's yeast

作　　者：姜友军[1] 张云松[1] 王仁国[1] 尹元江[1] 曾武[1] 肖朝萍[2] 

机构地区：[1]四川农业大学生命科学与理学院,雅安625014 [2]中国科学院成都有机化学研究所,成都610041

出　　处：《环境科学学报》2011年第7期1386-1395,共10页Acta Scientiae Circumstantiae

基　　金：四川农业大学"双支计划"基金~~

摘　　要：研究了用KMnO4修饰面包酵母菌对溶液中Cd2+的吸附作用,探讨了不同KMnO4浓度、pH、吸附时间、Cd2+初始浓度、修饰酵母菌用量等5个因素对KMnO4修饰面包酵母菌吸附Cd2+的影响.结果表明,随着修饰剂KMnO4浓度的增大,修饰面包酵母菌的吸附能力增强,KMnO4浓度达到20mmol·L-1时,吸附能力是相同条件下原菌的2倍.在pH为5.0～7.0范围内,吸附效果最好;反应30min后,吸附可达到平衡;Cd2+初始浓度为100mg·L-1时,吸附基本达到饱和;KMnO4修饰面包酵母菌的最佳用量为6g·L-1左右.KMnO4修饰面包酵母菌吸附Cd2+的过程适宜用准二级速率方程来描述,而Langmuir方程对其吸附等温线的描述效果最好.SEM、FTIR、XPS等分析结果表明,面包酵母菌主要通过表面的羟基、羧基、氨基、磷酰基等基团进行吸附.KMnO4修饰可使面包酵母菌表面变得较为粗糙,表面结构发生变化,提高菌表面吸附镉活性位点的数量.同时,KMnO4氧化面包酵母菌时在表面被还原成纳米MnO2和Mn2+,其对Cd2+吸附也起到了协同作用.The adsorption of aqueous Cd2＋ by baker＇s yeast modified by KMnO4 was explored.Several factors,including the concentration of KMnO4 used to modify the baker＇s yeast,pH,adsorption time,the initial concentration of Cd2＋,and the dosage of KMnO4 modified yeast,were investigated to evaluate the adsorption effect.The results showed that the adsorption capacity of modified baker＇s yeast was improved with the increasing KMnO4 concentration and the optimal amount of KMnO4 modified baker＇s yeast was about 6 g · L-1.When the concentration of KMnO4 was 20 mmol · L-1,the adsorption capacity was double that of untreated yeast under the same conditions.In the range of pH 5.0~7.0,the adsorption was the best;adsorption equilibrium was reached at 30 min.When the initial concentration of Cd2＋ was 100 mg · L-1,KMnO4 modified baker＇s yeast attained saturated adsorption.Kinetics studies indicated that the adsorption behavior can be described with a pseudo-second-order rate equation.The Langmuir adsorption isotherm exhibited the best fit to the experimental data.The biosorbent was characterized with SEM,FTIR and XPS,the results show that Cd2＋ was adsorbed by functional groups on the surface of the biosorbent,such as —OH,—COOH,—NH2 and —PO3-4.KMnO4 modification not only makes the surface of baker＇s yeast become rougher,but also changes the surface structure,and increases the number of active sites.Simultaneously,on the surface of baker＇s yeast,KMnO4 was reduced to nano-MnO2 and Mn2＋,which also played a role in the adsorption of Cd2＋.

关 键 词：面包酵母菌 KMNO4 化学修饰 Cd2+ 生物吸附 

分 类 号：O643.36[理学—物理化学]