交联海藻酸钠固定化的腐殖酸多孔性薄膜对铀(Ⅵ)的吸附性能及机理  

Characteristics and mechanism of uranium(Ⅵ)adsorption on glutaraldehyde crosslinked humic acid-immobilized sodium alginate porous membrane

作　　者：谢水波[1,2] 段毅[1] 刘迎九[1] 王劲松[1] 刘金香[1] 

机构地区：[1]南华大学污染控制与资源化技术湖南省重点实验室,湖南衡阳421001 [2]南华大学铀矿冶生物技术国防重点学科实验室,湖南衡阳421001

出　　处：《化工学报》2013年第7期2488-2496,共9页CIESC Journal

基　　金：国家自然科学基金项目(11175081;21177053);湖南省科技计划重点项目(2011SK2015)~~

摘　　要：采用戊二醛交联海藻酸钠固定化的腐殖酸,制备得到多孔性薄膜(GA-HA/SA),用于去除含铀废水中的铀(Ⅵ)。通过静态吸附实验,研究了pH值、初始浓度、接触时间、温度对GA-HA/SA吸附U(Ⅵ)效果的影响,进行了吸附过程的热力学与动力学分析;通过红外光谱(FTIR)、扫描电镜(SEM)、X射线能谱(EDS)探讨了相关吸附机理。实验结果表明,pH值为6时吸附效果最好,吸附在60min基本达到平衡。吸附过程符合Langmuir和Dubinin-Radushkevich(D-R)等温模型;25℃时,最大吸附容量为312.5mg·g-1。吸附动力学过程符合准二级速率方程(R2>0.99),吸附速率的控速步骤为颗粒内扩散。GA-HA/SA对U(Ⅵ)的吸附是自发的吸热反应。SEM-EDS、FTIR和D-R模型分析结果表明,与U(Ⅵ)相互作用的基团主要是羧基,且GA-HA/SA吸附U(Ⅵ)的机理表现为离子交换。Glutaraldehyde crosslinked humic acid-immobilized sodium alginate was used to develop a novel porous composite membrane adsorbent（GA-HA/SA）for the removal of uranium（Ⅵ）ions from uranium-contained wastewater.The physicochemical properties of GA-HA/SA before and after adsorption were investigated by FTIR,SEM and EDX methods.To investigate the effects of experimental parameters on adsorption behavior,batch experiments were performed by changing solution pH,initial concentration of U（Ⅵ）ions,contact time and temperature.The experimental data fit the Langmuir and Dubinin-Radushkevich（D-R）isotherm models well.The adsorption process can be described by pseudo-second-order kinetic model and the correlation coefficient is more than 0.99.The adsorption rate is controlled mainly by intra-particle diffusion.The calculated thermodynamic parameters such as Gibbs free energy change,enthalpy change and entropy change indicate that the adsorption of U（Ⅵ）onto GA-HA/SA is feasible,spontaneous and endothermic in nature.FTIR and mean free energy of adsorption for D-R isotherm show that the adsorption of U（Ⅵ）ions onto GA-HA/SA involves an ion exchange process.

关 键 词：多孔性薄膜 铀(Ⅵ) 热力学 动力学 速率控制 吸附机理 

分 类 号：O647.3[理学—物理化学] TQ317[理学—化学]