Highly ordered metal ion imprinted mesoporous silica particles exhibiting specific recognition and fast adsorption kinetics

Abstract

We prepared highly ordered metal ion imprinted mesoporous silica (IIMS) through co-condensation using a combination of molecular imprinting technology and traditional mesoporous materials. Copper ion is used as the template. Besides the periodic hexagonal structure, nano-sized wall thickness, and large surface area, it is found that the IIMS has highly specific recognition ability for the template. The imprinting factor of IIMS exhibits a maximum value of 3.7 at pH 2.5. The material shows fast binding kinetics for Cu²⁺ (complete equilibrium reach only within 5 min) and the saturation adsorption capacity reaches up to 0.39 mmol g⁻¹. Homogeneous binding sites are confirmed by the Langmuir isothermal model and the Langmuir–Freundlich isothermal model. The heterogeneity index is 0.992 with a value similar to those found for molecularly imprinted polymers prepared using covalent imprinting. The recovery of the silica stays above 90% after six extraction–stripping cycles. Furthermore, the silica has significant potential for water treatment applications.