Treatment of Synthetic Industrial Effluent Aiming at the Removal of Glyphosate by Means of Advanced Oxidation

Abstract

Objective: The purpose of this study was to assess the efficiency of an advanced oxidative process gradually applying different oxidative agents, i. e. UV, TiO2 and O3, to evaluate the removal efficiency of a commercial composition of glyphosate from an aqueous matrix.    Theoretical framework: In Brazil, approximately 150 million liters of glyphosate are consumed per year, representing 30% of the total pesticides used, which can contaminate surface water due to aerial or terrestrial spraying, erosion and runoff, improper disposal of commercial packaging and cleaning of contaminated spray tanks. Advanced oxidative processes have emerged as an alternative to the degradation of glyphosate since they have high efficiency in reducing organic contaminants to an acceptable limit with a low operating cost.    Method: Experimental consisted of a benchtop-scale system, composed of a batch reactor with a 25W UV lamp inside and a feeding pump in a recirculation reservoir. It was responsible for performing the removal of glyphosate by means of an advanced oxidative process after receiving TiO2 and O3 application.    Results and conclusion: The photolysis process obtained an efficiency of 24.69%, the photocatalytic oxidation process with TiO2 obtained 37.78%, and the photocatalytic ozonation with TiO2 obtained 45.46% efficiency in 60 minutes of reaction. The possible formation of byproducts after one hour of reaction due to the increase in concentration was also observed, since it was not possible to distinguish glyphosate from other compounds in the analysis method applied.   Implications of the research: As demonstrated by the results of the experimental assays, the advanced oxidative technique proved to be very efficient to make the removal of a commercial composition of glyphosate from an aqueous matrix.     Originality/value: It has been shown that it is possible to remove glyphosate in an efficient way, using a highly efficient fast technique.