Selective adsorption and separation of Cs(I) from salt lake brine by a novel surface magnetic ion-imprinted polymer

Abstract

A new Cs(I) magnetic ion-imprinted polymer (Cs(I)-MIIP) aimed at the selective adsorption and separation of Cs(I) from salt lake brine was prepared. The Fe3O4@SiO2 was used as supporter, Cs(I) as template ion, and carboxymethyl chitosan as functional monomer. The product was characterized by Fourier transform infrared spectra, XRD, energy-dispersive spectrometry, scanning electron microcopy, thermogravimetric analysis, and vibrating sample magnetometer. The adsorption of the Cs(I)-MIIP in solution was investigated, which indicated the maximum adsorption capacity was 36.15 mg·g−1 under the optimum conditions. The pseudo-first-order kinetic model and the Freundlich isotherm model were applied to predict the adsorption process of Cs(I) onto Cs(I)-MIIP. Selectivity experiments showed that the relative selectivity coefficient (k′) were 24.995, 1.73, 1.43, 4.83, and 1.63 to Cs(I)/Li(I), Cs(I)/Na(I), Cs(I)/K(I), Cs(I)/Rb(I), and Cs(I)/Sr(II) binary solutions, higher than those of NIP, respectively. Furthermore, the Cs(I)-MIIP was successfully applied to the enrichment and separation of Cs(I) from the salt lake brine of Qinghai, with satisfactory Cs(I) recovery rates.