Preparation of Ion-Imprinted Polymer Based on Magnetic Attapulgite and its Adsorption Properties on Cd (II)
摘要
To address the problem of excessive Cd (II) content in selenium-rich soil and water in Enshi region, this experiment utilized ion imprinting for selective adsorption of cadmium, which made the separation of selenium and cadmium possible. A novel attapulgite-based Cd(II) ion-imprinted polymer (AF-IIP) was prepared with the surface imprinting technique, using magnetic attapulgite as the matrix and (3-mercaptopropyl) trimethoxysilane (MPS) as the functional monomer. SEM, XRD, VSM, FT-IR and EDS elemental analysis were performed to confirm the structural transformations and compositional changes of the materials during the preparation process. The optimal pH, optimal time, adsorption kinetics and adsorption isotherms during the adsorption of Cd (II) by ion-imprinted polymers were investigated. The experimental results showed that the optimum pH of the adsorption process was 6.0 and the maximum adsorption amount was 49.0 mg·g−1. In the presence of competitive ions, the adsorption capacity of AF-IIP for Cd (II) is much larger than that of Se ions, indicating that AF-IIP has good selectivity. The adsorption reaction conformed to the Langmuir isotherm model and kinetic data were more suitable to be explained by pseudo-second-order model. Furthermore, XPS analysis confirmed that Cd(II) adsorption primarily occurs via interactions with thiol (-SH) groups. In addition, regeneration tests have shown that AF-IIP was reusable and stable.