Degradação do herbicida Diuron por processos oxidativos avançados homogêneos utilizando um esterilizador ultravioleta comercial.

Abstract

Herbicides are extensively used in agricultural areas in Brazil and are frequently mentioned in the literature as contaminating agents in surface, groundwater and drinking water. The water treatment conventionally used in the country is often not effective in removing these contaminants, therefore highlighting the importance of new techniques capable of degrading them. In this scenario, advanced oxidative processes (AOPs) have been studied as an alternative for treating these compounds in aqueous media. In this work, the objective was to investigate the degradation of the herbicide Diuron at initial concentrations around 3 mg/L, employing different advanced oxidative processes (AOPs), including Fenton, photo-Fenton, photo-Peroxidation and direct photolysis using a commercial ultraviolet sterilizer. . For each method, the effectiveness in relation to hydrogen peroxide consumption, herbicide degradation rate and reaction kinetics was evaluated. The kinetic model chosen to fit the experimental data was the one proposed by Chan and Chu. The results revealed satisfactory degradation rates for the photo-Fenton, photolysis and photo-Peroxidation processes, reaching degradation rates of 61%, 54% and 66%, respectively. However, none of the processes managed to achieve complete degradation of the herbicides, indicating the need to optimize the methods used. The experimental kinetic data were well fitted to the proposed kinetic model, confirming a pseudo-first order kinetics for Diuron. Keywords: Herbicides. Photo-peroxidation. Reaction kinetics.