Optimizing Glyphosate Removal from Water Using a Peracetic Acid-Assisted Advanced Oxidation Process: A Response Surface Methodology Approach

Glyphosate (GLY), one of the most used pesticides in the world, has been frequently detected in water, posing chronic and remote hazards to human health and the environment. Consequently, it has become necessary to develop efficient and sustainable treatment processes able to remove GLY from the polluted aquatic environments. In this context, the use of advanced oxidation processes is of great interest, as it allows for a significant reduction in concentrations of recalcitrant pollutants. In this study, peracetic acid (PAA) was used for the first time to remove GLY from water. In particular, the process parameters (oxidant dose, activation by UV radiation, GLY concentration, process time) were optimized using central composite design (CCD) and response surface methodology (RSM). The degradation of the pollutant, i.e., GLY, was monitored by ion chromatography, optimizing the instrumental parameters. During the process, residual oxidant concentrations were also constantly monitored using reference methods (i.e., UV-visible spectroscopy). Based on the results obtained, the best GLY removals (over 90%) were achieved under the following conditions: a PAA/GLY molar ratio of 3 (concentration of 3.0 mg/L for GLY and 4.0 mg/L for PAA), UV irradiation, and a process time of 45 min. The possibility of achieving total glyphosate removal by using small amounts of oxidant increases the environmental sustainability of the proposed aquatic pollution mitigation strategy.