Estudo da degradação do cetoprofeno em meio aquoso por fotólise direta e peroxidação fotoassistida

Abstract

Water is a fundamental natural resource for the maintenance of life, however, uncontrolled population growth and anthropic actions have been impacting the quality of this resource due to the dumping of residues and contaminants in various aquatic matrices around the world. Among these pollutants, there are emerging pollutants such as drugs that are found in a concentration range from µg.L-1 a ng.L-1. In most cases, part of the drugs and their metabolites remain in the treated water after being subjected to conventional effluent treatment, being capable of generating adverse effects on the ecosystem. The use of advanced oxidative processes (AOP) becomes an alternative capable of removing micropollutants from contaminated aquatic environments. Faced with this problematic, the objective of this work was to study the degradation of ketoprofen by direct photolysis and photo-assisted peroxidation and to evaluate the toxicity before and after the degradation by both processes against Artemia salina. The tubular reactor used in the experiments consisted of a radiation system formed by a UV lamp with a wavelength of 254 nm, inserted concentrically to a titanium cylinder, with batch operation and recirculation of the solution. The experimental design 22 was used to evaluate the variables time (60 and 120 minutes) and flow (100 and 300 L.h-1) in ketoprofen degradation. For the toxicological test, they were performed in duplicate for each initial and final sample of the degradation experiments, inserting 15 Artemias salinas in each tube in a period of 24 hours under constant aeration. The direct photolysis method reached a maximum degradation of 30.72%, while for the photo-assisted peroxidation method it obtained 73.07%. The two processes achieved their maximum conversions in the upper limits of the experimental design with a time of 120 minutes and a flow of 300 L.h-1, however, only the time was statistically significant at a confidence level of 95%.The toxicity found for the initial samples of ketoprofen are greater than the final samples, after treatment, indicating that the products generated in its degradation are less toxic than the drug itself. Initial samples showed maximum toxicity of 46.7%. There was a decrease in the toxicity of the final samples, the highest percentage observed was 33.3% for direct photolysis and 20% for photo-assisted peroxidation.