Abstract
Caffeine, when identified in surface water and drinking water, is classified as a contaminant of emerging concern. The emergence of these compounds occurs due to the direct discharge of sewage into the rivers, as well as through conventional techniques currently applied in the treatment of effluents and drinking water that do not completely remove these contaminants. In this context, the removal of such substances in aqueous solution has been studied by different techniques, standing out heterogeneous photocatalysis. In the photocatalytic reaction, several factors may contribute to the photocatalytic performance of the semiconductor, such as material structure, composition, textural properties, among others. To improve these characteristics, some procedures can be adopted, such as heat treatments and addition of metals to the surface of the material. In this perspective, the objective of this work was to characterize and evaluate the pure commercial TiO2, also the commercial TiO2, with the addition of 8% by mass of Fe and Ag, in the degradation of the caffeine contained in the water. The results of the experimental tests and the characterization of the materials indicated that, under the conditions used, 8%Ag-8%Fe/TiO2 bimetallic catalyst was the material with the highest catalytic activity followed by 8%Ag/TiO2, 8%Fe/TiO2 and Pure TiO2, while pure TiO2 was similar to the photolysis test, in which there was no satisfactory caffeine degradation. These results emphasize that the composition and structure of the catalysts applied to the heterogeneous photocatalysis has great importance in the yield of the catalyst in the reaction.
