Sorption materials based on ethylene glycol dimethacrylate and methacrylic acid copolymers for rare earth elements extraction from aqueous solutions

Macroporous copolymers of ethylene glycol dimethacrylate and methacrylic acid containing immobilized molecules of Alizarin red S and similar polymers imprinted by gadolinium ions were synthesized by free radical bulk polymerization method. Sorption properties of two pairs of the polymers with cross-link ratio of 85.7 and 92.6% were compared. The resulting materials were characterized by scanning electron microscopy and infrared spectroscopy. Sorption performance of the polymers synthesized toward gadolinium ions was investigated. It has been found that the maximum removal of gadolinium ions from solutions is observed at pH 6. The experimental data on gadolinium ion interaction with the sorbent surface were shown to fit Langmuir adsorption theory. Maximum gadolinium sorption capacity of nonimprinted polymers with cross-link ratio of 85.7 and 92.6% is 19.4 and 14.9 mg/g, respectively. Sorbent selectivity for rare earth ions was studied. According to the obtained results, sorbents under study reveal affinity to triple-charged ions. Tetrad effect observed in rare earth distribution patterns reflects chemical nature of sorption on such polymers.