La ozonización fotocatalítica como tratamiento para la eliminación de contaminantes emergentesestudio de distintas fuentes de radiación y fotocatalizadores basados en TiO₂, WO₃ y óxido de grafeno

Abstract

This research is focused on the use of photocatalytic ozonation to remove micropollutants from urban wastewaters. Specifically, it aims to overcome some limitations of this technology by using sustainable radiation sources, catalysts active under visible light and supported photocatalyst. Using primidone as probe compound, both, WO3 and TiO2 doped with graphene oxide, showed activity under visible light (solar or 420 nm LEDs). However, any of them bring any beneficial effects compared to TiO2 P25. Using the latter and UVA LEDs (365 nm), a pseudoempirical kinetic model capable to simulate primidone removal and mineralization in ultrapure water has been proposed. With the aim of stabilizing the existence of synergy between processes and their origin, the water matrix, pH and alkalinity effects on the efficiency of the different system involved in the PCOz has been determined using suspensions of TiO2 P25 and UVA LEDs. Results showed that synergies development relies on water matrix characteristics rather than oxidation systems interactions. Finally, a TiO2-P25 immobilized photocatalyst over mullite ceramic foams were synthetized and used to the elimination of a pharmaceuticals compound mixture in urban wastewaters by PCOz. Results showed a greater photoactivity of supported photocatalyst than achieved with TiO2 suspensions. These experiments also showed the importance of secondary effluent organic matter photolysis in the removal of micropollutants.