Preparation and optimization of diatom-based cadmium ion-imprinted materials

Abstract Ion imprinting technology has attracted much attention in recent years because of its specific recognition performance. In this study, an environment-friendly and inexpensive diatom was selected as the substrate material, and a novel Cd2+ imprinted adsorption material was synthesized using surface ion imprinting technique with 3-mercaptopropyltrimethoxysilane (MPS) as the functional monomer, Cd2+ as the template ion, and epichlorohydrin (ECH) as the cross-linking agent. The synthesis factors were optimized using the response surface method with the adsorption amount as the response value. Results showed that the best adsorption effect was achieved when 1:1 ratio of MPS and ECH and a stirring time of 93 min were used. The optimized imprinted as well as non-imprinted materials were characterized using SEM, FT-IR, TG and XPS, and the results showed that MPS was successfully grafted on the diatomaceous earth surface. The competition experiments in the ternary system showed that the optimized imprinted material was significantly more selective for Cd2+ than other ions. The results of regeneration experiments showed that the imprinted material had reproducibility and structural stability. And it provides a new idea for the removal of Cd2+ in actual wastewater.