Study of the Photoassisted Sonoelectrochemical Process for Degradation of the Pesticides Ametryn, Diuron and Hexazinone

Water contamination from pesticides in industrial and agricultural effluents has significant environmental impacts, necessitating the development of effective treatment technologies. This article discusses the use of a combined electrochemical, photochemical, and sonochemical approach to degrade pesticides like ametryn, diuron, and hexazinone. A bench-scale electrochemical flow reactor with a Ti/Ru0.3Ti0.7O2 anode, Ti counter-electrode, and NaCl as the electrolyte was utilized. Process optimization involved varying electric current and NaCl concentration, with free chlorine species (FCS) production as the response variable. Optimal conditions were achieved at 0.88 mol L–1 [NaCl] and 0.78 A current. This photoassisted sonoelectrochemical process effectively degraded the pesticides, achieving total organic carbon (TOC) removal rates of 91, 94, and 77% for ametryn, diuron, and hexazinone, respectively. High-performance liquid chromatography (HPLC) analysis showed near-total removal for ametryn and diuron and 80.7% for hexazinone. Kinetic studies indicated that the degradation followed a pseudo-first-order model, with rate constants increasing approximately 1.8-2.5 times under the combined process compared to the electrochemical method. Additionally, this triple-combined approach enhanced current efficiency, reduced energy use, and improved overall system energy efficiency, proving to be an effective and promising treatment method.