Comparison of the processes photo-Fenton and photocatalysis with TiO2 supported on non-woven fabric using a LED radiation in the degradation of the pharmaceutical meloxicam.

A comparison was made between homogeneous and heterogeneous advanced oxidative processes using TiO2 supported on non-woven fabric (NWF) in the degradation of the pharmaceutical meloxicam, using a LED radiation. Degradation tests were performed using homogeneous photoperoxidation, Fenton, and photo-Fenton processes. The photo-Fenton process promoted the greatest degradation. The conditions that led to the best results were then used to perform a kinetic study. After 300 min, the system stabilized, reaching 95% degradation. The experimental data followed a pseudo-first order kinetic law. The photocatalyst characterization results indicated a good reproducibility of the superposition method, indicating that the support process was efficient. Among the heterogeneous processes evaluated, the TiO2sup/LED process was selected, since the photocatalyst results did not show significant differences between the degradations achieved. In the kinetic study, the system was stabilized after 180 min, with a degradation of 94%. The experimental data also obeyed pseudo-first order kinetic law. When comparing the two processes, the degradation was similar, although photocatalysis was able to minimize the toxicity of the solution and reduce the chemical oxygen demand by 78% while the photo-Fenton only reduced 48%. Moreover, photocatalysis required 32% less energy than the photo-Fenton process under the same conditions. The photocatalysis with TiO2sup and LED radiation, therefore, proved to be effective for the degradation of meloxicam.