坡缕石粘土对Cu^(2+)的吸附热力学  

Adsorption Thermodynamics of Copper from Aqueous Solution on Palygorskite Clay

作　　者：郝艳玲[1] 范福海[1] 刘再满[1] 

机构地区：[1]兰州交通大学化学与生物工程学院,甘肃兰州730070

出　　处：《矿物学报》2011年第1期113-117,共5页Acta Mineralogica Sinica

基　　金：甘肃省自然科学研究基金计划(0803RJZA107)

摘　　要：将坡缕石粘土分离提纯后作为吸附剂,通过对水中Cu2+的静态吸附实验,考察了时间及介质pH值对吸附效果的影响,并对吸附平衡和吸附热力学特征进行了探讨。结果表明:在实验条件下坡缕石粘土对水中的Cu2+离子具有较强的吸附作用,吸附平衡时间约为60 min,pH值对吸附效果有显著的影响,吸附量随pH值的升高而增加,当平衡溶液pH>7时吸附率超过99%;吸附平衡与Langmuir方程的符合程度优于D-R方程和Freundlich方程,由Langmuir方程拟合饱和吸附量为33.0～34.0 mg/g,由D-R方程得平均吸附能Es为13 kJ/mol,吸附过程为离子交换反应;吸附过程吸热,吸附焓为16.97 kJ/mol,吸附Gibbs函数在-27～-24 kJ/mol之间,吸附熵大于零,吸附过程可自发进行。Effects of adsorption time and pH were studied through the test of statical adsorption of Cu^2＋ ions in waters on palygorskite clay based on purification,with the discussion on the adsorption isotherms and the thermodynamic characteristics.Results showed that the equilibrium could be reached in about 60 min under the condition of experiment temperature and initial concentrations.Effect of pH on adsorption was evident;the adsorption amount increased with increasing pH,and the disposal rate could exceed 99% when pH〉7.The adsorption isotherms were better fitted to Langmuir equation than D-R equation or Freundlich equation,and the saturated adsorption capacity calculated from Langmuir isotherm was 33.0～34.0 mg/g.The magnitude of sorption energy computed from D-R equation was 13 kJ·mol^-1,implying chemical ion-exchange mechanism of the adsorption process.The adsorption were endothermic processes,with the changing adsorption enthalpy of 16.97 kJ·mol^-1,and the changing adsorption Gibbs function in the rang of-27～-24 kJ·mol^-1.The adsorption entropy changes were all positive.The adsorption processes were spontaneous.

关 键 词：坡缕石粘土 提纯 吸附 铜离子 热力学 

分 类 号：O647.3[理学—物理化学] P578.964[理学—化学]