Degradation of simazine by photolysis of hydrogen peroxide Fenton and photo-Fenton under darkness, sunlight and UV light

Abstract

The study presents the results of the degradation of simazine at concentrations of 4 mg/L and 0.5 mg/L by means of different Advanced Oxidation Processes: photolysis of hydrogen peroxide under sunlight and UV light, Fenton and photo-Fenton under sunlight and UV light in ultrapure water at laboratory scale. The aim of the study was to optimize some of the main operating variables involved in the process: reaction time, concentrations of iron and peroxide, light sources and pH, employing D-optimal and Full-factorial design. Using contour plots from the D-optimal design, the concentrations of iron and peroxide, sunlight and UV radiation were found to be the factors that most influence the advanced oxidation processes employed in this study. Full-factorial analysis allowed us to establish the time, concentrations of iron and hydrogen peroxide and operating variables that most affect the degradation of simazine under sunlight and UV radiation. The degradation kinetics were likewise determined, establishing that the kinetic constants obey the following ascending order of effectiveness: kphotolysis under sunlight < kphoto-Fenton under sunlight < kUV < kphotofenton under UV radiation <kphotolysis under UV radiation. Finally, among the different advanced oxidation processes applied to the degradation of simazine in ultrapure water, it was determined that the H2O2/UV process provides the highest level of pesticide removal.