Pharmaceuticals are not removed by conventional processes, being determined in different aqueous matrices. Therefore, in this study the simultaneous degradation of gemfibrozil (GEM), hydrochlorothiazide (HCTZ) and naproxen (NAP) in surface water by advanced oxidation processes was evaluated. As can be seen in Table 1, high values of rate constants (k) and lower values of half-life time (t_1/2) were obtained using the photo-Fenton process (FeOx/H₂O₂/UV-A) followed by photoperoxidation (H₂O₂/UV-C) and heterogeneous photocatalysis (TiO₂/H₂O₂/UV-A). The t_1/2 for the photo-Fenton process was, on average, sixteen (GEM), six (HCTZ) and nine (NAP) times shorter than the other processes evaluated. Moreover, it presented the lowest treatment cost per m³ of contaminated water, considering the reduction of the initial concentration of each compound by an order of magnitude. Thus, the photo-Fenton process may be used as an alternative of treatment for the removal of such contaminants.

Table 1. Kinetic parameters obtained during the pharmaceuticals degradation by different advanced oxidation processes under optimized conditions. Initial conditions: [GEM] = [HCTZ] = [NAP] = 1.8 µmol L^–1; pH 6.0.