Ion-Imprinted Polymers Based on Hollow Silica with Yeasts as Sacrificial Supports for Sr2+ Selective Adsorption

Abstract

Surface ion-imprinting technique combined with a sacrificial support process was applied to synthesize Sr2+ ion-imprinted polymers (Sr-IIPs) in which yeast cells were used as sacrificial supports. The synthesized polymers were characterized by Fourier transmission infrared spectrometry, scanning electron microscope, transmission electron microscope and nitrogen adsorption–desorption analysis. The results indicated that Sr-IIPs possessed a relatively good dispersion and large surface area. Batch mode adsorption experiments were carried out to investigate the specific adsorption equilibrium, kinetics and selective recognition properties of Sr-IIPs. Sr-IIPs exhibited a fast kinetics adsorption capacity and high selectivity for adsorption of Sr2+. Under optimal experimental conditions, the adsorption of Sr2+ onto Sr-IIPs followed the pseudo-second-order kinetics model and was well-described by the Langmuir isotherm model. The monolayer adsorption capacity at 318 K was 60.61 mg g−1 for Sr-IIPs, which is over three-times that of NIPs. Thermodynamic parameters confirmed that the adsorption of Sr2+ onto Sr-IIPs was a spontaneous and endothermic process within the studied temperature range (298–318 K).