Synthesis of hydrotalcite and titanium dioxide (HT-TiO2) composite for application in heterogeneous photocatalytics processes

Abstract

The objective of the study was to synthesize a composite of hydrotalcite and titanium dioxide (HT-TiO2) for application in heterogeneous photocatalytic processes to the degradation of organic pollutants in aqueous media. The composites were characterized by X-ray diffraction and surface area, then an experimental design was carried out to evaluate the influence of pH and temperature on the adsorption capacity of pollutants against the anionic dye indigo carmine using a kinetic study. Photocatalytic tests were carried out in a chamber equipped with a UV lamp and hydrogen peroxide as an auxiliary oxidant in degradation. The adsorption results corroborated with the order of surface areas obtained, where the adsorption capacity followed the order of HT, HT-TiO2 5 %, HT-TiO2 10 %, and TiO2, respectively, obtaining removals up to 96.94 %. For the heterogeneous photocatalytic tests, the best conditions of the experimental design were used for each semiconductor, with a removal of up to 99.96 % being observed in 2 h. The use of hydrogen peroxide as an auxiliary oxidant reduced the reaction time to 45 min, demonstrating how joint effluent treatment techniques can increase the speed and efficiency of the process.