Kinetic study of glyphosate degradation in wet air oxidation conditions

Abstract

Glyphosate is one of the most widely used herbicides in the world against perennial and annual weeds. It has been reported to be a micro pollutant, and its degradation in different wastewater treatment processes must be studied. For that purpose, the kinetics of wet air oxidation of glyphosate was studied in an autoclave reactor at a temperature range of 423–523 K and under a total pressure of 15 MPa. Oxidation reactions obeyed the first-order kinetics with respect to glyphosate concentration. The activation energy for glyphosate oxidation was found to be equal to 68.4 kJ mol−1. Furthermore, the possible reaction intermediates and main end products of glyphosate degradation in the wet air oxidation process were identified and quantified using UV-spectrophotometry and liquid chromatography coupled to high resolution mass spectrometry. A degradation pathway for glyphosate oxidation was proposed.