改性蒙脱石吸附亚甲蓝的研究

STUDY ON ADSORPTION OF MODIFIED MONTMORILLONITE FOR METHYLENE BLUE

取钠型蒙脱石和钙型蒙脱石 ,经铜离子交换反应使其改性。研究改性前后蒙脱石吸附亚甲蓝的能力及其受温度、介质pH值和离子强度的影响 ,并就吸附等温线和相关热力学参数进行分析。结果表明 :不论是钠型还是钙型蒙脱石 ,经铜离子处理后 ,二者吸附亚甲蓝的能力均有所下降 ,但改性钠型蒙脱石下降的幅度要大于改性钙型蒙脱石 ;介质pH值和离子强度对蒙脱石和改性蒙脱石吸附性能的影响有差异 ,而吸附温度对各吸附剂吸附性能的影响程度则相近 ;改性蒙脱石和蒙脱石吸附亚甲蓝的等温线均能较好的符合BET和Langmuir等温方程 ,在 2 98.15K下 。

Both Na-montmorillonite and Ca-montmorillonite were modified by using the method of ion exchange reaction with Cu2+. Methylene blue (MB) was used as a probe molecule for investigating the adsorptive properties of parent and modified montmorillonites, and the effects of temperature, pH value and ionic strength of medium on this adsorption. At the same time, adsorption isotherms and thermodynamic parameters about MB adsorption on the respective adsorbents were analyzed. The results show that treatment with Cu2+ reduces the ability of both Na-and Ca-montmorillonite to adsorb MB molecule, but the reductive degree for modified Na-montmorillonite is relatively great as compared to modified Ca-montmorillonite. There are different effects of pH value and ionic strength of medium on the adsorptive capacities of parent and modified montmorillonite, but adsorptive temperature exhibits a similar influence on the interaction between the respective adsorbent and MB. The data obtained from MB adsorption on the tested adsorbents fit in with the BET and Langmuir equations. Also, the adsorption processes are spontaneous in thermodynamics at 298.15 K.