Infrared spectroscopic study of dynamics and complexation mechanism in chemosorption of ions of metals by acrylate hydrogels

The paper presents a spectroscopic study of the complexation of ions of various metals on the surface of polyelectrolyte polymer hydrogels. The object of the study was a polyelectrolyte hydrogel based on a copolymer of acrylic acid and acrylamide, which sorbs the ions of various metals by means of chemisorption mechanism with the formation of chelate complex compounds on its surface. IR spectra are obtained for complex compounds of a polymeric hydrogel with metals in the sorption process at definite intervals of time. We study the sorption dynamics and the complexation mechanism of divalent and trivalent metals with polyelectrolyte hydrogel based on a copolymer of acrylic acid and acrylamide. It is found that the formation rate of complexes on the surface of the polymer hydrogel depends on the type of metal. It has been shown that such metals as cobalt, lead, cadmium, nickel, manganese and aluminum form mainly a carboxylate type of complexes, zinc forms an acrylamide type and copper, iron and chromium form complex compounds of mixed type. The performed researches can find application at synthesis of polymeric materials for selective sorption of certain kinds of metals. The obtained results indicate the principal possibility of hydrogel application based on acrylamide and acrylic acid copolymer as sensor materials for the detection of ions of various metals in aqueous solutions.