Degradação de uma mistura dos fármacos Genfibrozila, Hidroclorotiazida e Naproxeno pelo processo foto-Fenton

Abstract

In this work, the simultaneous degradation of the pharmaceuticals Gemfibrozil - GEM (0,5 mg L-1), Hydrochlorothiazide - HCTZ (1,0 mg L-1) and Naproxen - NAP (0,9 mg L-1) by the photo-Fenton process with artificial radiation was evaluated. Firstly, the effect of Fe2+ concentration (0.25, 0.5, 1.0 and 2.0 mg L-1) on degradation of pharmaceuticals by classic photo-Fenton process in deionized water using 1.0 mg L-1 H2O2 at initial pH 2.7 was studied. Then, 1.0 mg L-1 Fe2+ was the best concentration of the catalyst. After, the influence of H2O2 concentration (1.0, 2.0 e 4.0 mg L-1) on degradation of pharmaceuticals in deionized water was evaluated, being obtained best results in the presence of 2.0 mg L-1 H2O2. In addition, the influence of the catalyst (Fe2+; Fe3+; Ferrioxalate - FeOx and Iron (III) Citrate - FeCit) at initial concentration of 18 μmol L-1 for simultaneous degradation of pharmaceuticals in deionized water, by photo-Fenton process using 2.0 mg L-1 H2O2 at pH 2.7 was verified. The FeOx catalyst allowed complete degradation of NAP, GEM and HCTZ after 6, 10 and 25 min, respectively. Moreover, new experiments of photo-Fenton process (using FeOx and FeCit) at near neutral pH (5.0 and 7.0) in deionized water were performed. The complete degradation of the pharmaceuticals was only achieved using FeOx at pH 5.0 and after 60 min of treatment. After this same treatment time, by-products with low toxicity, not exceeding 25% inhibition for Vibrio fischeri were obtained. For surface water experiments, the effect of Fe3+ concentration (1.0, 3.0 and 5.0 mg L-1) on degradation of the pharmaceuticals by modified photo-Fenton process with FeOx, using 4.0 mg L-1 H2O2 and pH 6.7 (natural of this matrix) was evaluated. The ideal concentration of Fe3+ for pharmaceuticals degradation was 3.0 mg L-1. Subsequently, the effect of C2O42- binder addition (in proportion of 1:3, 1:6, 1:9 and 1:12 relative to Fe3+/C2O42-) by modified photo-Fenton process with FeOx in surface water (stream), with 4.0 mg L-1 H2O2 concentration, 3.0 mg L-1 Fe3+ and pH 6.7 was verified. The complete degradation of the pharmaceuticals was achieved using a molar iron/organic ligand ratio of 1:9 Fe3+/ C2O42-, after 15 min of treatment. Therefore, the modified photo-Fenton process with FeOx showed good performance in degradation of the pharmaceuticals evaluated in surface waters.