Studies on Preparation and Recognition Characteristic of Surface-Ion Imprinting Material IIP-PEI/SiO₂ of Chromate Anion

Abstract

An anion-imprinted material with high performance for recognizing chromate anions was prepared by adopting the novel surface-molecular imprinting technique put forward by our research group previously. Functional macromolecule polyethyleneimine (PEI) was first grafted on the surfaces of micron-sized silica gel particles in the manner of “grafting to,” forming the grafted particle PEI/SiO_2. Afterwards, the ion imprinting was carried out towards the macromolecule PEI grafted on the surface of the silica gel particles by using ion as a template and ethylene glycol diglycidyl ether (EGGE) as crosslinking agent, and chromate ion-surface imprinted material IIP-PEI/SiO₂ was obtained. The binding characteristic of IIP-PEI/SiO₂ for ion was studied with both static and dynamic methods. The experimental results show that IIP-PEI/SiO₂ has excellent binding affinity and high recognition selectivity for chromate anion. Before imprinting, the grafted particles PEI/SiO₂ have similar adsorption capacities for both chromate anion and phosphate anion that was used as a contrast substance. However, after imprinting, the binding capacities of IIP-PEI/SiO₂ towards phosphate anion decrease remarkably, whereas the binding capacity of IIP-PEI/SiO₂ for chromate anion still remains higher, leading to a very high selectivity coefficient (12.23) of IIP-PEI/SiO₂ for ion with respect to the ion. IIP-PEI/SiO₂ is a separation material with high performance.

Keywords:

• chromate anion
• graft polymerization
• ion recognition
• polyethyleneimine
• surface imprinting technique