Abstract

In the following work, red mud (RM) and ferrosilicomanganese fines (FeSiMn) were used as clay materials in the synthesis of hybrid hydrogels. These inorganic phases are obtained as waste from production processes carried out by the Venezuelan mining industry. The research is focused on the development of new applications for these wastes, using them to improve the properties of conventional hydrogels. In this study, these inorganic phases were modified through two treatments aimed at reducing their pH. The first treatment used synthetic seawater and the second treatment was acidification with HCl. For the synthesis, acrylamide (AAm) was used as a monomer, and N,N`-methylenebisacrylamide (NMBA) as a cross-linking agent. The hydrogels were characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), and the ability to absorb Co2+ and Fe2+ ions was determined by inductively coupled plasma optical emission spectroscopy (ICP-OES). The results show that modifications decreased the water absorption capacity of the hydrogels, in the same way the micrographs obtained by SEM revealed that modification with HCl was the one that had the most effect on the surface morphology of hydrogels, increasing the population of pores with lengths less than 4 μm from 21% to 74% in the PAAm/FeSiMn hydrogels. The results are explained by new interactions between the inorganic phases and the PAAm matrix and indicate that modifications made constitute a way to control the microstructure and properties of the hybrid hydrogels.