Hidrogéis híbridos de poliacrilamida e amido: síntese, caracterização e estudo da aplicabilidade em águas contaminadas

Abstract

Starch obtained from Tommy Atkins mango kernel was applied in the production of acrylamide hydrogels. These hybrid hydrogels were synthesized by freeradical reaction in aqueous medium and characterized by infrared, 13C NMR, SEM, XRD, rheometry and degree of swelling. The different molar proportions of acrylamide/starch and MBA used in the reaction feed led to changes in viscoelastic properties, gelling kinetics, swelling degree and surface morphology. The synthesized hydrogels were evaluated for adsorption potential of phenolic pollutants from contaminated waters, proving to be efficient in removing these residues. The equilibrium adsorption (Qeq) values ranged from 2 to 21 mg/g and were strongly dependent on acrylamide, starch and MBA concentrations in the system. The type of adsorption isotherm that best fitted was that of the Freundlich model, with R2 values between 0.95 - 0.97. Hydrogels also showed efficiency in the release of these phenolic pollutants, indicating the possibility of reuse of these materials. In addition, in a second strand of applicability in contaminated waters, hydrogels were able to incorporate silver nanoparticles in their three-dimensional networks, in order to obtain nanocomposites with potential to detect phenolic pollutants in waste water. It was possible to detect the pollutant in the order of 10-8 mol. L-1 using the surface amplified Raman spectroscopy (SERS) technique.