乙二胺硅胶功能材料对Cu^(2+)的吸附特性

Adsorption Properties of Ethylenediamine-grafted Silica Gel on Cu^(2+) Ions

以氯丙基三氯硅烷为架桥剂,将乙二胺偶合接枝到硅胶表面,合成了乙二胺硅胶功能材料(EDA/SiO2),研究了其对Cu2+的吸附热力学和动力学特性.结果表明,在研究的温度及浓度范围内,Cu2+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3.5~5.5;测定的Cu2+吸附平衡数据符合Langmuir模型,吸附过程的吸附焓、自由能和吸附熵的计算结果显示吸附为吸热过程,升温有利于吸附的进行;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.

Ethylenediamine-grafted silica gel（EDA/SiO2） was synthesized by using chloropropyltrichlorosilane（CPTCS） as anchor,ethylenediamine as modification agent,and its properties of adsorption thermodynamics and kinetics on Cu2＋ were studied.The experimental results showed that pH value of Cu2＋ solution affected adsorption capacity of EDA/SiO2 significantly,and the best pH range was pH3.5-5.5 for Cu2＋ adsorption.The adsorption equilibrium data on Cu2＋ could be fitted by Langmuir model.The results of calculating the adsorption enthalpy,free energy and adsorption entropy showed that this adsorption is endothermic process and it is conducive to adsorption with increasing temperature.Adsorption kinetic data could be fitted by the pseudo-second-order kinetic equation,and the fitting kinetic constants were related with initial solution concentration.