Catalisadores de nióbio promovidos com Fe e Cu aplicados na fotodegradação do ácido salicílico

Abstract

The inadequate treatment of domestic and industrial effluents is one of the contributing factors for the presence of emerging contaminants in surface waters, since the conventional methods used in water treatment plants are insufficient in the removal of these micropollutants. This work presents the application of Nb2O5 catalysts, promoted with copper and iron, in the heterogeneous photocatalysis method for the degradation of salicylic acid. Different calcination temperatures were used in the synthesis of the catalysts in order to evaluate their influence on the photocatalytic activity. In order to evaluate the performance of the catalyst regarding its reaction medium, different pH ranges and, subsequently, the addition of formic acid were employed in the study. The results showed that the Cu/Nb2O5 catalyst presents the best performance, reaching a degradation potential of 28% of salicylic acid at a lower calcination temperature of 400 ºC and acid medium (pH = 3,2). The addition of formic acid, however, had no positive impact on the photocatalytic activity while the natural pH of the solution was maintained. Based on the results, the degradation of salicylic acid by Nb2O5 catalysts tested in this work is not efficient enough as TiO2 catalysts under the same conditions, which show a degradation potential of 88% with only 60 min of UV radiation exposure.