Mechanistic approach of the combined (iron–TiO2) photocatalytic system for the degradation of pollutants in aqueous solution: an attempt of rationalisation

Autor: Michèle Bolte, Gilles Mailhot, Jaromír Jirkovský, Josef Krýsa, Hana Měšt’ánková
Rok vydání: 2005
Předmět:
Zdroj: Applied Catalysis B: Environmental. 57:257-265
ISSN: 0926-3373
DOI: 10.1016/j.apcatb.2004.11.003
Popis: Kinetics of oxidative photodegradation of Monuron (3-(4-chlorophenyl)-1,1-dimethylurea) in different photocatalytic systems (iron, TiO 2 and combined system iron + TiO 2 ) were investigated and compared. The influence of iron addition on TiO 2 photocatalyst and of TiO 2 on the photocatalytic cycle Fe(III)/Fe(II) were carefully studied. A very positive effect of iron addition was observed. This phenomenon was more and more pronounced when TiO 2 concentration was lower. In a suspension of TiO 2 (24 mg L −1 ) with addition of Fe(III) (3 × 10 −4 mol L −1 ) the measured rate constant was similar to that obtained in a suspension of TiO 2 with a concentration more than 20 times higher (500 mg L −1 ). The mechanistic approach carried out in this study allows us to identify the main reactions governing the combined system and a photochemical cycle was proposed. The optimisation of the photocatalytic systems was obtained when each photocatalyst plays a specific role: Fe(III) as a main OH radicals source and TiO 2 as an oxidizing agent of Fe(II).
Databáze: OpenAIRE
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