EVALUATION OF AFFINITY FOR THE REMOVAL MG 2+ AND NI 2+ IONS BY POLY(ACRYLAMIDE-CO-ORGANIC ACIDS) COPOLYMERS HYDROGELS

Abstract

By a free radical polymerization reaction poly(acrylamide-co-itaconic acid), poly(AAm-co-AI); and poly(acrylamide-co-maleic acid), poly(AAm-co-AM); copolymers hydrogels were synthesized; with the purpose of studying the effect of the chemical structure of these di-carboxylic acids on the absorbing capacity of Ni 2+ and Mg 2+ ions. The swell ability and swelling kinetics of the hydrogels were calculated with the swelling index (Hp) and the metal ion absorption capacity was measured by inductively coupled plasma optical emission spectroscopy (ICP-OES) analysis. Studies indicated that both hydrogels have higher affinity for the Ni 2+ ions. Also, when comparing the effectiveness of the acid monomers used, for the removal of the cations, it was obtained that the poly(AAm-co-AI) hydrogel is more effective, and is able to remove twice the Mg 2+ ions compared to the poly(AAm-co-AM) hydrogel. The results are explained in terms of the structural difference of the acid monomers used and the electron configuration of the ions evaluated, which is related to the polymer-ion interactions that occur during the ion absorption process.