Non-specific degradation of chloroacetanilide herbicides by glucose oxidase supported Bio-Fenton reaction

Abstract

Bio-Fenton reaction supported by glucose oxidase (GOx) for producing H2O2 was applied to degrade persistent chloroacetanilide herbicides in the presence of Fe (III)-citrate at pH 5.5. There were pH decrease to 4.3, the production of 8 mM H2O2 and simultaneous consumption to produce center dot OH radicals which non-specifically degraded the herbicides. The degradation rates followed the order acetochlor approximate to alachlor approximate to metolachlor > propachlor approximate to butachlor with the degradation percent of 72.8%, 73.4%, 74.0%, 47.4%, and 43.8%, respectively. During the Bio-Fenton degradation, alachlor was dechlorinated and filtered into catechol via the production of intermediates formed through a series of hydrogen atom abstraction and hydrogen oxide radical addition reactions. The current Bio-Fenton reaction leading to the production of center dot OH radicals could be applied for nonspecific oxidative degradation to various persistent organic pollutants under in -situ environmental conditions, considering diverse microbial metabolic systems able to continuously supply H2O2 with ubiquitous Fe(II) and Fe (III) and citrate.