铜离子在印迹壳聚糖/Al_2O_3上的吸附-脱附特性

Characteristics of Adsorption and Desorption of Copper Ion on Imprinted Chitosan/Al_2O_3

采用表面接枝和表面印迹技术,以正硅酸乙酯改性后的Al2O3粉末为载体、壳聚糖为功能单体,制备了Cu2+印迹复合材料(IIP/Al2O3),用于选择性分离Cu2+.研究了IIP/Al2O3对Cu2+的动态吸附,利用Thomas,Yoon-Nelson和Wolborska模型分析IIP/Al2O3吸附Cu2+过程,考察了动态条件下Cu2+的最佳洗脱条件.结果表明,当Cu2+浓度100mg/L、柱高37.25 mm、流速1.0 mL/min和pH=5时,IIP/Al2O3的穿透吸附容量和动态吸附容量分别为4.03和15.68 mg/g,Cu2+去除率为45.55%;Thomas和Yoon-Nelson模型能很好地拟合IIP/Al2O3对Cu2+的吸附;在柱高37.25 mm、洗脱液流速1.0 mL/min的条件下,15 mL 0.6 mol/L盐酸溶液对Cu2+的脱附率高达99.54%,脱附作用时间短,Cu2+易回收.

In order to separate selectively Cu^2＋, Cu^2＋ imprinted polymer/aluminium oxide （IIP/Al2O3） was prepared by the surface-grafting and surface imprinting techniques. Al2O3 powder modified with tetraethylorthosilicate was used as the carrier, and chitosan as the functional monomer. Dynamic adsorption of Cu2＋ on IIP/Al2O3 was studied, and Thomas, Yoon-Nelson and Wolborska models were adopted to fit to the experimental data. Further, experiments were performed to optimize the parameters of dynamic desorption. The results indicated that breakthrough capacity and dynamic adsorption capacity of the IIP/Al2O3 were 4.03 and 15.68mg/g, respectively, and removal rate of Cu^2＋ reached 45.55% at Cu^2＋ inlet concentration of 100 mg/L, IIP/Al2O3 column height of 37.25 mm, flow rate of 1.0 mL/min and pH value of 5. The Thomas and Yoon-Nelson models fit well to the experimental data of dynamic adsorption. 15 mL hydrochloric acid solution at 0.6 mol/L resulted in the desorption rate of 99.54% for Cu^2＋ at IIP/Al2O3 column height of 37.25 mm and flow rate of 1.0 mL/min. Desorption time was short, and Cu^2＋ was easily recycled.