Propranolol degradation through processes based on the generation of hydroxyl free radical.

Pharmaceutical substances such as propranolol (PRO) are an emerging class of aquatic contaminants that have increasingly been detected in ground and surface water. For this reason, the aim of this study was to evaluate the efficiency of advanced oxidation systems for the PRO degradation. The tests started with anodic oxidation (AO), using 0.01, 0.05, and 0.1 M Na2SO4 as the supporting electrolyte and 16, 32, 48, and 64 mA cm-2 as current density. Under the best conditions obtained in AO, the electro-Fenton (EF) process was reviewed, where the effect of Fe2+ was analyzed with 5, 10, 15, and 20 mg Fe2+ L-1. The Fenton reaction (FR) was studied using the Fe2+ concentration that promoted the highest percentage of PRO removal and initial concentration of 16 mg L-1 of H2O2, in addition to these conditions, in the photo-Fenton (PF) system, the effect of UV light with wavelengths 254 and 365 nm were evaluated. The results obtained showed that the degradation efficiency of the EF > AO > PF > FR system along with a percent removal of 94.52, 90.4, 25.97, and 4.4%, respectively. The results showed that PRO can be removed through the studied systems, with the EF system being the most efficient.

Degradation of gestodene (GES)-17α-ethinylestradiol (EE2) mixture by electrochemical oxidation.

Evidence of the negative effects of several pharmaceutical molecules, such as hormones and steroids, on the environment can be observed throughout the world. This paper presents the results of the anodic oxidation of the mixture of gestodene steroid hormones and 17 α-ethinylestradiol present in aqueous medium. The tests were conducted in an undivided cell containing a working volume of 50 mL, using a Na2SO4 solution as support electrolyte and boron-doped diamond electrodes. The experiments were adjusted to the structure of a 33 factorial design. The evaluated factors were: support electrolyte concentration (0.02, 0.05, and 0.10 M), pH of the reaction media (2, 3, and 4), and current density (16, 32, and 48 mA cm-2). Under the optimum conditions (0.02 M Na2SO4, pH 4, and current density of 32 mA cm-2), the degradation of at least 93% of the initial concentration of gestodene and 17α-ethinylestradiol was reached in a reaction time of 5 and 10 min, respectively. The complete degradation of both molecules required 15 min of reaction. Under these conditions, the degradation profile of the pharmaceutical mixture as each one of the active ingredients, followed a pseudo-first order kinetic behavior (kmix = 0.0321, kGES = 0.4206, and kEE2 = 0.3209 min-1).

Application of the Fenton process in the elimination of helminth eggs.

This study relates to a method for evaluating the degradation efficiency of Ascaris lumbricoides eggs through a Fenton reaction, using hydrogen peroxide (H2O2) at 100, 250, and 500 mg/L, ferrous sulfate (FeSO4) at 458 mg/L Fe(2+) and pH values of 3, 4.5, and 6. The experiments were conducted according to a 3(2) experimental design, with 1:1, 3:1, and 5:1 (H2O2/Fe(2+)) molar ratios. The oxidation and flocculation stages were performed at 130 rpm during 2 hours and at 25-30 rpm during 20 min, respectively. As a result of the Fenton reaction, an average of 91.2% Ascaris lumbricoides egg degradation was achieved at pH 6 using a 500 mg/L dose of H2O2 and a 3:1 (H2O2/Fe(2+)) molar ratio. Thus, this process is an alternative for eliminating parasites that are resistant to conventional disinfection processes and significantly reduces the human health hazard they represent.