改性海泡石对重金属Pb^(2+)的吸附机理研究

Investigation on Absorption Mechanism of Pb^(2+) by Modified Sepiolite

利用盐酸和十六烷基三甲基溴化铵(CTAB)对海泡石进行了修饰改性,研究了改性修饰后的海泡石对Pb^(2+)的吸附性能,着重对其吸附Pb^(2+)的动力学和热力学进行了研究,并探讨了该过程的吸附机理。实验结果表明,改性海泡石对Pb^(2+)的吸附符合准二级动力学模型和Langmuir吸附等温方程。同时改性修饰后的海泡石对Pb^(2+)的吸附热力学数据表明过程的焓变ΔH^0=21.89 k J/mol,熵变ΔS^0=136.5 J/(mol·K),对应温度下吸附自由能ΔG0小于零。因此,该过程为自发的吸热过程,其吸附活化能E_a=5.420 k J/mol。

The sepiotite was modified by the treatment of hydrochloric acid and hexadeeyl trimethyl ammonium bromide （CTAB）, forming an efficient adsorbent for the adsorbed research of Pb^2＋ in aqueous solutions. Importantly, the kinetic and thermodynamic behaviors of the Pb^2＋ adsorption were studied. The experiment results indicated the adsorption of Pb^2＋ satisfied pseudo second order mode and the Langmuir isotherm equation. ΔH^0= 21.89 kJ/mol, ΔS^0= 136. 5 J/（mol·K）, AGO 〈0, revealed that the whole adsorption process was spontaneous endothermic reaction, and the activation energy was 5. 420 kJ/mol. Furthermore, the adsorption mechanism was also clarified.