Comparative Study of the Degradation of the Diclofenac Drug Using Photo-Peroxidation and Heterogeneous Photocatalysis with UV-C and Solar Radiation

Diclofenac has been detected in water and terrestrial matrices, causing severe changes in the environment. This is due to the fact that it is one of the most widely used nonsteroidal anti-inflammatory drugs in the world. The advanced oxidation processes (AOPs) of photo-peroxidation and heterogeneous photocatalysis were tested in this work using UV-C and solar radiation to degrade diclofenac in aqueous solutions. To monitor the efficiency of the degradation processes an ultrahigh performance liquid chromatography with ultraviolet detection at a wavelength of 285 nm was applied. Both processes were found to be efficient (> 78%) after 60 min of treatment, being possible to determine the reaction kinetics for each one of them. Intermediate formation was also observed after 60 min which were also degraded by increasing the treatment time to 120 min. For the treatments using UV-C radiation, an order of 1.0 was observed, while the treatments that applied solar radiation obtained an order of 0.2 for the photocatalysis and 0.8 for photo-peroxidation.