Advanced oxidation of commercial herbicides mixture: experimental design and phytotoxicity evaluation

Abstract

In this work, the suitability of the UV/HO process for commercial herbicides mixture degradation was studied. Glyphosate, the herbicide most widely used in the world, was mixed with other herbicides that have residual activity as 2,4-D and atrazine. Modeling of the process response related to specific operating conditions like initial pH and initial HO to total organic carbon molar ratio was assessed by the response surface methodology (RSM). Results have shown that second-order polynomial regression model could well describe and predict the system behavior within the tested experimental region. It also correctly explained the variability in the experimental data. Experimental values were in good agreement with the modeled ones confirming the significance of the model and highlighting the success of RSM for UV/HO process modeling. Phytotoxicity evolution throughout the photolytic degradation process was checked through germination tests indicating that the phytotoxicity of the herbicides mixture was significantly reduced after the treatment. The end point for the treatment at the operating conditions for maximum TOC conversion was also identified.

Technologies Employed in the Treatment of Water Contaminated with Glyphosate: A Review

“…Both studies compared the results obtained from a mathematical model with the experimental ones. Vidal et al reported 80% glyphosate remotion and 70% TOC remotion after 12 treatment hours, these results were similar to the percentage remotion reported by López et al [62].…”

“…Furthermore, formaldehyde, formic acid and nitrate, ammonium, and phosphate ions were detected as final degradation products of glyphosate [59]. Other authors as Vidal et al [61] and López et al [62] have studied the H 2 O 2 /UVC system for degradation of commercial glyphosate herbicide mixture in water. Both studies compared the results obtained from a mathematical model with the experimental ones.…”

Study and optimization of the UV/H2O2 process to treat contaminated wastewater coming from a pesticide formulation plant

“…Other authors carried out the same analysis but, unlike those mentioned above, they did it with a mixture of pesticides, also in an aqueous solution. This is the case of López et al (2018), who studied the degradation of pesticides mixture (glyphosate, 2,4-D and atrazine) through the UV/H 2 O 2 process. In this case, an improvement was observed in the conversion to intermediate pH ( 5) with a low R, while with a higher R the improvement was at a pH = 10.…”

Treatment technologies and degradation pathways of glyphosate: A critical review

“…In order to overcome the cost of photocatalyst production, the combination of hydroperoxide and UV radiation (H 2 O 2 /UV) has been reported to treat glyphosate at higher concentrations (up to 90 mg.L −1 ). This process is quite simple and convenient (López et al, 2018;Manassero et al, 2010;Vidal et al, 2015). During H 2 O 2 /UV process, the H 2 O 2 concentration is an important parameter.…”