巯基功能化膨润土吸附Pb^2＋的动力学和热力学研究  

KINETICS AND THERMODYNAMICS OF ADSORPTION OF Pb^(2+) ON THIOL-FUNCTIONALIZED BENTONITE

作　　者：熊琼仙[1] 陈文[1,2] 朱霞萍[1] 杭行[1] 赵秋香[3] 刘文华[3] 

机构地区：[1]成都理工大学材料与化学化工学院,四川省矿产资源化学高校重点实验室,成都610059 [2]电子科技大学生命科学与技术学院,成都610054 [3]广东省物料实验检测中心,广州510080

出　　处：《离子交换与吸附》2012年第5期432-441,共10页Ion Exchange and Adsorption

基　　金：广东省财政厅地质专项(No.2011208);横向委托项目(No.HP0030);横向委托项目(No.HG0103)

摘　　要：研究了自制巯基功能化膨润土(TFB)对Pb2+的吸附行为,考察了溶液的pH值、离子强度、吸附时间和温度对吸附平衡的影响,并对吸附过程进行了动力学与热力学研究。结果表明,常温下,吸附时间为60min、0.1mol/L的KNO3、pH=6.0、5.0g/L TFB对200mg/L的Pb2+的吸附率达到85.4%以上,TFB对Pb2+的吸附动力学符合准二级动力学方程;TFB对Pb2+的吸附热力学符合Langmuir等温线方程和Dubinin–Radushkevich(D-R)等温线方程,表明吸附主要发生在TFB表面的活性区域,属于单分子层吸附,其吸附平均活化能E在8~16kJ/mol范围内,表明该吸附过程为化学吸附,不同温度下的吸附热力学的吉布斯自由能以及熵变和焓变表明该吸附过程为自发放热反应。The adsorption behavior of Pb^2＋ on Thiol-functionalized bentonite （TFB） was studied using batch technique under a function of contact time, pH, ionic strength and temperature. And then the kinetics and thermodynamics of the adsorption process was studied in detail. The results showed that the removal efficiency of Pb^2＋ by TFB could reach 85.4%, when the initial concentration of Pb^2＋ was 200rag/L, the liquid/solid ratio was 5g/L, pH was 6.0, concentration of KNO3 was 0.1mol/L and adsorption time was 60min at room temperature. The adsorption of Pb^2＋ on TFB followed pseudo-second-order kinetic model well. On the other hand, the adsorption of Pbz~ on TFB followed Langmuir and Dubinin-Radushkevich （D-R） isotherm models well. Based on the fitting results of Langmuir model, the adsorption was regarded as monolayer adsorption and taken place at the functional groups/binding sites on the surface of the adsorbent. And from the D-R isotherm model, adsorption energy E was between 8kJ/mol and 16kJ/mol, which indicated that the adsorption of Pb^2＋ was chernisorption process. The thermodynamic parameters （the Gibbs free energy, entropy and enthalpy） of the adsorption were discussed at different temperatures and the results demonstrated that the adsorption process was spontaneous and exothermie.

关 键 词：巯基功能化膨润土 PB2+ 吸附 动力学 热力学 

分 类 号：TQ425.1[化学工程]