Photodegradation of tebuconazole mediated by a novel hybrid phenalenone based photosensitizer

Abstract

The aim of this work is to evaluate the use of phenalenone (PN) grafted to sand in the photodegradation of tebuconazole (TEB). PN was covalently attached to sand via click reactions between functionalized sand and PN derivatives. The photodegradation study was conducted in an annular reactor equipped with immersed UV and visible lamps. In the first step the photodegradation of TEB was studied in presence of free PN. The influence of the molar ratio = PN/TEB was investigated; a maximal effect was observed with R close to 769; beyond this value a shielding effect appeared. The use and the lifetime of the sand-bound PN were studied and the photodegradation mechanism was investigated. Covalent binding of photosensitizer to sand resulted in a 80 nm red shift of the PN absorption band in the visible region along with an important increase in degradative efficiency. PN-Sand was more stable under visible irradiation. The main mechanism was the type II with some contribution of type I.