Degradation kinetics and mechanism of hazardous metribuzin herbicide using advanced oxidation processes (HC & HC+ H2O2)

Abstract

Metribuzin (C8H14N4OS) is a selective triazinone group of herbicide. In the present work, the degradation of Metribuzin has been systematically investigated in aqueous solution using Hydrodynamic Cavitation (HC) and HC combined with Hydrogen Peroxide (HC+H2O2). Initially, various experiments have been performed to investigate the effects of parameters like the pump inlet pressure (2–10 bar), initial concentration of the compound (20–100 mg/l) and operating pH (2.5–7) on the Metribuzin degradation. The percentage degradation of the Metribuzin was monitored by High Performace Liquid Chromatography (HPLC). Maximum degradation of Metribuzin obtained was around 14.50% with HC at optimized operating conditions. Significant degradation of Metribuzin was achieved to the tune of 70.92% with a combined HC+H2O2 process. TOC removal of 22% was also obtained using a combined (HC+H2O2) approach. In the present work, energy efficiency comparison of HC and HC+H2O2 treatment has also been made. The identification of Metribuzin degradation by-products was done using High Resolution-Liquid Chromatography Mass Spectrophotometer (HR-LCMS). Pseudo 1st order kinetics fitted well for the Metribuzin degradation using Advanced Oxidation Process (AOP). HC coupled with H2O2 can be efficiently employed for Metribuzin degradation.