Cu^2+印迹壳聚糖/聚乙烯醇膜的制备及其吸附性能研究

Preparation of Cu^(2+) Imprinted Chitosan/Polyvinyl Alcohol Membrane and Its Adsorption Properties

基于壳聚糖对金属离子的螯合机理,同时采用离子印迹法和共混法改性壳聚糖膜,制备了Cu^(2+)印迹壳聚糖/聚乙烯醇膜(CS(Cu^(2+))/PVA),并研究了其对Cu^(2+)的吸附性能。利用SEM、 FT-IR对其进行表征,并探讨了各因素对吸附效果的影响,结果表明:当PVA添加量为7.5%, Cu~(^(2+))初始浓度为100 mg·L-1,吸附剂添加量为0.01 g, pH=5.00时, CS(Cu^(2+))/PVA对Cu^(2+)的吸附量最大,为182.1 mg·g-1,是壳聚糖膜(CS)吸附量的1.9倍。吸附在90 min内达到平衡,吸附等温线既符合Langmuir模型,也符合Freundlich模型。吸附动力学符合拟二阶动力学模型。3次循环使用后,吸附量仍可达到102.7 mg·g^(-1)。在有Pb^(2+)存在的混合溶液中,其对Cu^(2+)的吸附量为150.39 mg·g-1,是对Pb^(2+)吸附量(22.14 mg·g-1)的7倍,表现出优异的吸附选择性。

Based on the chelating mechanism of chitosan on metal ions, chitosan/polyvinyl alcohol membranes containing Cu^2＋template（CS（Cu^2＋））/PVA） were prepared by ion-imprinting and blending. Its adsorption properties for Cu^2＋were studied. The membrane was characterized using SEM and FT-IR. The influence of various factors on the adsorption effect was discussed. The experimental results showed that CS（Cu^2＋）/PVA had the maximum adsorption capacity of Cu2 ＋, and the largest adsorption amount was 182.1 mg·g^-1, which was 1.9 times of chitosan membrane under following conditions： the PVA content was 7.5%; the initial concentration of Cu^2＋was 100 mg·L-1; the amount of adsorbent was 0.01 g; and the pH was 5. The adsorption reached equilibrium within 90 min. The adsorption isotherm conformed to both the Langmuir model and the Freundlich model. The adsorption kinetics conformed to a pseudo second-order kinetic model. After three cycles, the adsorption capacity still remained at 102.7 mg·g^-1. In the mixed solution containing Pb^2＋, its adsorption capacity for Cu^2＋was 150.39 mg·g^-1, which was 7 times higher than that of Pb^2＋（22.14 mg·g^-1）, showing an excellent adsorption selectivity.