Avaliação da degradação de benzofenona-3 por processo UV/H2O2

Abstract

Chemical photoprotectors are a group of compunds that act in the absorption of UVrays, and therefore are widely used in cosmetic formulations and personal care products. Recents studies classifies this composts as emergent pollutants due to their potential as endocrine disruptors, their persistence in the environment and bioaccumulation in aquatic organisms. The conventional effluent treatment systems do not have shown effectiveness in the removal of these composts and, therefore, it's necessary the use of alternative technologies. This project had as objective to avaliate the Advanced Oxidation Process UV/H2O2 efficiency in the degradation of a model compound of a chemical photoprotector, the benzophenone-3 (BP3). The BP3 solution 1 mg L-1 was prepared with 0.2% (v/v) of ethanol due to the low solubility of the compound in water. It's concentration was monitored by HPLC-DAD and the merit parameters of the method were evaluated. Stability tests were elaborated and evaluated on days 01, 03, 06, 07, 14, 21 and 28. Treatment trials were administered in bench reactors, using as a radiation source a high pressure 125 W mercury vapor lamp inserted into the solution by a quartz bulb, during a 5 minutes period. The initial and final amounts of the hydrogen peroxide were determined by spectrophotometric (UV-Vis) methodologies. The chromatographic method was selective, linear and with limits of detection and quantification of 0.014 mg L-1 and 0.050 mg L-1, respectively. The study solution showed a 10% reduction in BP3 concentration in the first 7 days, remaining stable in the following weeks. The UV/H2O2 process proved to be efficient in degradation of the BP3 sample, with a removal greater than 90%. For H2O2 concentrations of 75 mg L-1, the process presented a maximum degradation in the order of 95%. Two solid phase extraction methodologies (SPE) were tested for different cartridges and did not obtain satisfactory results, making it impossible to quantify the samples.