DEGRADATION OF 2,4-DICHLOROPHENOXYACETIC ACID BY IN-SITU PHOTOGENERATED FENTON REAGENT

The oxidation of 2,4-dichlorophenoxyacetic acid using ZnO as photocata lyst is investigated. This photodegradation process depends on the mas s of semiconductor and on the light intensity, being almost independen t of the pH of the solution, except in alkaline media and near to the point of zero charge of the semiconductor. The experimental data show that the photodegradation process follows Langmuir-Hinshelwood kinetic s. The role of Fe(II) ions in the yield of the 2,4-D photodegradation is analyzed. It is shown that the addition of a small amount of Fe(II) increases the rate of photodegradation. Also, an increase in the rate of 2,4-D dechlorination is observed, although a lower degree of miner alization is detected in presence of Fe(II) ions than in their absence .