Photocatalytic degradation of salicylic acid employing TIO2 and ZNO in aqueous suspension / Degradação fotocatalítica do ácido salicílico empregando TIO2 e ZNO em suspensão aquosa

Abstract

The photocatalytic degradation of salicylic acid (SA) in reduced concentration (14.5 µmol L-1) was investigated using TiO2 and ZnO as photocatalysts under irradiation with UV light using UV-Vis spectrophotometry and HPLC analysis. The effect of different catalysts and catalyst loading, kinetic analysis, and dissolution of ZnO using the experimental conditions adopted were evaluated in acidic medium (pH = 3.0). Chronic ecotoxicity tests of the effluent from the reactions were conducted employing a concentration of 1 g L-1 of photocatalysts. The results showed that TiO2 and ZnO presented very similar performance for the SA degradation, whose profile followed first-order kinetics. The dissolution of ZnO observed was low using the experimental conditions adopted. Chronic ecotoxicity tests carried out showed that the use of ZnO/UV system for degradation of SA leads to a product with significant harmful effects on Ceriodaphnia dubia, even at reduced concentrations of the effluent from the reaction.