pH、离子强度、时间和温度对Cd(Ⅱ)在伊利石上吸附的影响

Effects of pH, Ionic Strength, Time and Temperature on the Sorption of Cd(Ⅱ) to Illite

摘要: 用批量平衡法研究了pH值、离子强度、反应时间和温度对Cd(Ⅱ)在伊利石上吸附的影响。并用Lagrange准二级动力学方程、Langmuir等温线方程、Freundlich等温线方程以及D-R等温线方程对实验数据进行拟合。结果表明：pH值和离子强度对Cd(Ⅱ)在伊利石上的吸附均有明显的影响，低pH值下Cd(Ⅱ)在伊利石上的吸附主要是通过外层络合和离子交换；而在高pH值下Cd(Ⅱ)的吸附主要是通过内层络合作用进行；Cd(Ⅱ)在伊利石上的吸附动力学符合Lagrange准二级动力学方程；热力学符合Langmuir等温线方程；升高温度有利于Cd(Ⅱ)在伊利石上的吸附。

Abstract: The sorption of Cd(Ⅱ) on illite was studied as a function of pH, ionic strength, time and temperature under ambient conditions using batch technique. The results indicate that sorption of Cd(Ⅱ) on illite is strongly dependent on pH values and ionic strength. At low pH, the sorption is dominated by outer-sphere surface complexation and ion exchange on illite surfaces, whereas inner-sphere surface complexation is the main sorption mechanism at high pH. The adsorption of Cd(Ⅱ) on illite is found to follow pseudo-second-order kinetic model well. Sorption of Cd(Ⅱ) increase with increasing temperature and fit the Langmuir isotherm well.