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

被引:46
作者
Mest'ánková, H
Mailhot, G [1 ]
Jirkovsky, J
Krysa, J
Bolte, M
机构
[1] Univ Clermont Ferrand, Lab Photochim Mol & Macromol, F-63177 Clermont Ferrand, France
[2] Inst Chem Technol, Dept Inorgan Technol, Prague 16626 6, Czech Republic
[3] Acad Sci Czech Republ, Inst Phys Chem, Prague 12823 8, Czech Republic
关键词
iron; TiO2; monuron; photodegradation;
D O I
10.1016/j.apcatb.2004.11.003
中图分类号
O64 [物理化学(理论化学)、化学物理学];
学科分类号
070304 ; 081704 ;
摘要
Kinetics of oxidative photodegradation of Monuron (3-(4-chlorophenyl)-1,1-dimethylurea) in different photocatalytic systems (iron, TiO2 and combined system iron + TiO2) were investigated and compared. The influence of iron addition on TiO2 photocatalyst and of TiO2 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 TiO2 concentration was lower. In a suspension of TiO2 (24 mg L-1) with addition of Fe(III) (3 x 10(-4) mol L-1) the measured rate constant was similar to that obtained in a suspension of TiO2 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)-O-center dot radicals source and TiO2 as an oxidizing agent of Fe(II). (c) 2004 Elsevier B.V. All rights reserved.
引用
收藏
页码:257 / 265
页数:9
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