Estudos de degradação de fármacos em meio aquoso por processos oxidativos avançados

Abstract

The use of PET as a support material for TiO2 films in advanced oxidation processes (AOPs) for water treatment was investigated. A green, low-cost immobilization procedure was developed and the amount of deposited photocatalyst ranged from 0.036 to 0.202 mg per cm2 PET. Photocatalytic activity of the films was evidenced by degrading paracetamol solutions under UV radiation. The highest kinetic constants were observed for at least 0.09 mg TiO2 per cm2 PET. Scan Electron Microscopy (SEM) and Energy-Dispersive X-ray (EDX) analyses indicated 0.15 mg TiO2 per cm2 PET as enough to provide complete covering of the PET support. Characterization analyses were performed with a film after 30 h of use in a UV/TiO2/O3 reactor. According to SEM analyses, the photocatalyst was not detached from the PET support, while EDX and gravimetric data indicated the possibility of the TiO2 to have been contaminated by compounds present in the solution during the treatment. Further experiments were performed, concerning the study of the degradation of the pharmaceuticals paracetamol, ibuprofen, ketoprofen, and naproxen. Degradation studies were carried out in a pilot-scale reactor, by using several AOP’s, namely direct photolysis, heterogeneous photocatalysis, and ozonation, either individually or simultaneously. Special attention was given to the identification of significant factors considered, in order to contribute to the optimization of systems in which such AOPs or their combination can be used. Also, the detection and indication of degradation products is presented.