Estudo da degradação de microcontaminantes em efluentes por radiação ultravioleta e processo oxidativo foto Fenton.

Abstract

The occurrence and identification of organic microcontaminants has attracted the interest of many researchers for the development and improvement in processes for the removal of these contaminants from effluents. In general, degradation of microcontaminants by conventional methods is very difficult, because of the low concentrations that they are found. Thus, the photo Fenton process and Ultraviolet Radiation (UV) has been a promising alternative for the removal of such water contamination. This study aims to perform the investigation of degradation, in effluent, of atrazine (ATZ) using the photo Fenton process and degradation of the pharmaceuticals propranolol (PRO) and metronidazole (MET) using UV radiation. In the ATZ (0,1 mg L-1) degradation study, UV-A photo Fenton process was used (H2O2= 5,0 mg L-1 e Fe2+ = 5,0 mg L-1), achieving a microcontaminant degradation of about 62 %, and the UV-C photo-Fenton process (H2O2 = 5,0 mg L-1 e Fe2+ = 5,0 mg L-1), reached about 98% of ATZ degradation. The analysis of organic matter removal during the photo Fenton treatment showed no significant change in the studied parameters. In the UV photolysis degradation study of the pharmaceuticals solutions (100 mg L-1) a degradation of 35% (PRO) and 50% (MET) was obtained after 8 hours of treatment, whereas using solar radiation a degradation of 36% (PRO) and 16% (MET) were obtained. From the kinetic constants and half-lives calculated, it was found that direct photolysis using solar radiation was so effective as the system using UV-C radiation to promote photodegradation of PRO, and for the MET results showed that the pharmaceutical has a higher degradation rate when the UV-C radiation was employed.