乙二胺硅胶复合材料对Zn2+的吸附特性

以γ-氯丙基三氯硅烷为偶联剂，将乙二胺偶合接枝在硅胶表面，合成对锌离子具有吸附作用的乙二胺硅胶复合材料（EDA/SiO2），考察了Zn2+溶液pH值、初始浓度、吸附温度和吸附时间等因素对复合材料吸附性能的影响。 结果表明,在研究的溶液浓度及温度范围内,Zn2+溶液pH值对EDA/SiO2的吸附量影响显著，吸附的最佳pH值范围在3.0~5.5；Zn2+的吸附平衡数据符合Langmuir吸附模型，热力学数据显示，EDA/SiO2对Zn2+的吸附行为为一吸热且自发进行的过程，升高温度有利于吸附，并对此吸附行为作了解释；吸附动力学数据可用拟二级吸附动力学方程描述，得到的吸附速率常数与溶液初始浓度有关。

The Adsorption of Zn2+ Cations on Ethylenediamine-grafted Silica Gel

Ethylenediamine-grafted silica gel materials(EDA/SiO2) for the adsorption of Zn2+ were prepared with the use of γ-chloropropyltrichlorosilane as coupling reagent and ethylenediamine as a surface-modifying reagent. The adsorption behavior of EDA/SiO2 for Zn2+ and the effects of pH in Zn2+ solution, initial concentration, adsorption temperature and time were studied. The experimental results show that the pH value of Zn2+ solution affected the adsorption capacity of EDA/SiO2 significantly, and the suitable pH range was pH 3.0~5.5 for the adsorption of Zn2+. The adsorption equilibrium data for Zn2+ could be fitted according to the Langmuir model. The results of the thermodynamic parameters of the adsorption of Zn2+ on EDA/SiO2 show that this adsorption is an endothermic spontaneous process and increasing temperature is conducive to the adsorption. An interpretation was given for this, adsorption behavior of Zn2+ on EDA/SiO2. Adsorption kinetic data could be fitted by the pseudo-second-order kinetic equation, and the fitting kinetic constants were related with the initial solution concentration.