铀在榕树叶上的吸附行为及其机理分析  

Adsorption Behavior of Uranium and Mechanism Analysis on Banyan Leaves

作　　者：夏良树[1] 谭凯旋[1] 王晓[1] 郑伟娜[1] 

机构地区：[1]南华大学化学化工学院,湖南衡阳421001

出　　处：《原子能科学技术》2010年第3期278-284,共7页Atomic Energy Science and Technology

基　　金：国家自然科学基金资助项目(10675059);湖南省高等学校科研委托项目资助(09w025)

摘　　要：通过静态吸附实验,研究了UO22+在榕树叶上的吸附行为,从热力学和动力学方面对吸附过程进行了分析,并通过红外光谱、扫描电镜探讨了吸附机理。结果表明:UO22+在榕树叶上的吸附是吸热过程,符合Freundlich等温吸附方程,相关系数达0.99以上;表面吸附是动力学控制的主要步骤,吸附动力学过程可用准二级吸附速率方程来描述,相关系数达0.999 8;榕树叶吸附铀是自发的、吸热的吸附反应;榕树叶对铀的吸附使细胞的表面形态发生了改变,在榕树叶吸附铀的过程中,UO22+主要与细胞表面的—OH、C=O、P—O及Si=O等基团螯合,形成配合物,因此,榕树叶吸附铀的机理表现为表面络合吸附机理。The adsorption behavior of uranium on banyan leaves was studied with static experiments.The adsorption process was analyzed in terms of thermodynamics and kinetics,and the adsorption mechanism was analyzed with FTIR and SEM.In the studied condition,the equilibrium adsorption data fit to Freundlich isotherms,with a relation coefficient greater than 0.99.The adsorption of uranium on banyan leaves is an endothermic process.Kinetic analysis shows that the adsorption rate is mainly controlled by surface adsorption.The process of adsorption can be described by an equation of Pseudo 2nd-order model.The calculation data are in good agreement with the experimental data,and the relation coefficient is 0.999 8.The thermodynamic data indicate that the synergistic uranium biosorption by banyan leaves is a spontaneous and endothermal adsorption process.The adsorption of uranium on banyan leaves changes the cell＇s surface form of banyan leaves.In the adsorption process,UO2^2＋ mainly chelates with —OH,C=O,P—O and Si=O etc.on the cell＇s surface and forms the complexes.The adsorption of uranium should be of surface coordination.

关 键 词：榕树叶 铀 吸附 机理 

分 类 号：O647.3[理学—物理化学]