Photo-Fenton degradation of a herbicide with simulated solar radiation. Kinetic model using the ferrioxalate complex.

ORLANDO M. ALFANO; LEANDRO O. CONTE; AGUSTINA V. SCHENONE; ENRIQUE ALBIZZATI

Barcelona

Congreso; 22nd IOA World Congress & Exhibition; 2015

International Ozone Association

A theoretical and experimental study of the homogeneous photo-Fenton degradation of herbicide 2,4-dichlorophenoxyacetic acid (2,4-D) is presented. First, different sources of iron in water solution were studied: sulphate, oxalate and citrate complexes. The behaviour of these complexes was evaluated by means of two parameters: (i) the photonic efficiencies of degradation and mineralization; and (ii) the quantum efficiencies of degradation and mineralization. The ferrioxalate system presented the best performance for conditions at pH = 5. From these results, a kinetic model derived from a reaction sequence is proposed using the ferrioxalate complex as iron source for conditions of pH close to neutrality. Operating the system with high radiation level and the highest concentration of hydrogen peroxide (R = 50), the conversion of 2,4-D after 180 min of reaction is close to 100% over the full range of working temperatures. Also, a good agreement between the kinetic model and experimental data, for a rather wide range of the operating variables, was observed.