Degradation of 4-chlorophenol mediated by Fe(III)-NTA in homogeneous and heterogeneous systems.

O. ABIDA; C. EMILIO; N. QUICI; R.T. GETTAR; M. LITTER; G. MAILHOT; M. BOLTE

WATER SCIENCE AND TECHNOLOGY

I W A PUBLISHING

Lugar: London; Año: 2004 vol. 49 p. 123 - 128

0273-1223

In this work, the comparison of 4-chlorophenol (4-CP) degradation by two different AOT processes has been performed: a) a homogeneous system with Fe(III)-NTA (1:1 complex), b) a TiO2/Fe(III)-NTA heterogeneous system. In both cases, NTA appears to play a positive role in the photochemical reaction. In the homogeneous system, the iron salt is the only absorbing species and is proved to be able to photoinduce 4-CP degradation ([4-CP] = 1-2 ´ 10-4 M, [Fe-NTA] = 3-9 ´ 10-4 M, pH 4, l = 365 nm). The progress of the reaction was positively affected by the Fe-NTA concentration, and the reaction kept going on even after the total disappearance of Fe-NTA. However, 4-CP complete degradation requires the presence of oxygen, otherwise the reaction stops. In the heterogeneous system ([4-CP] = 2.0 ´ 10-3 M, [Fe-NTA] = 1.0-2.0 ´ 10-3 M, [TiO2] = 0.1 and 1.0 g L-1, pH 3, l = 300-400 nm), an important effect of the complex on the degradation extent and on the initial reaction rate can be seen, which overcomes the effect of non-complexed Fe(III). This behavior is more important at the highest TiO2 concentration.