Photo-Fenton and Riboflavin-photosensitized Processes of the Isoxaflutole Herbicide

GATICA, EDUARDO; POSSETTO, DAVID; REYNOSO, AGUSTINA; NATERA, JOSÉ; MISKOSKI, SANDRA; DE GERÓNIMO, EDUARDO; BREGLIANI, MABEL; PAJARES, ADRIANA; MASSAD, WALTER A.

PHOTOCHEMISTRY AND PHOTOBIOLOGY

WILEY-BLACKWELL PUBLISHING, INC

Año: 2019 vol. 95 p. 901 - 908

0031-8655

The proherbicide Isoxaflutole (IXF) hydrolyzes spontaneously to diketonitrile (DKN) a phytotoxic compound with herbicidal activity. In this work, the sensitized degradation of IXF using Riboflavin (Rf), a typical environmentally friendly sensitizer, Fenton and photo-Fenton processes has been studied. The results indicate that only the photo-Fenton process produces a significant degradation of the IXF. Photolysis experiments of IXF sensitized by Riboflavin is not a meaningful process, IXF quenches the Rf excited triplet ( 3 Rf*) state with a quenching rate constant of 1.5 · 10 7  m −1  s −1 and no reaction is observed with the species O 2 ( 1 Δ g ) or O - 2 generated from 3 Rf*. The Fenton reaction produces no changes in the IXF concentration. While the photo-Fenton process of the IXF, under typical conditions, it produces a degradation of 99% and a mineralization to CO 2 and H 2 O of 88%. A rate constant value of 1.0 × 10 9  m −1  s −1 was determined for the reaction between IXF and HO˙. The photo-Fenton process degradation products were identified by UHPLC-MS/MS analysis.