Comparison of Diuron degradation by direct UV photolysis and advanced oxidation processes

The rates of Diuron elimination by some advanced oxidation processes (AOPs) such as Fe(III)/UV, Ferrioxalate/UV, Fe(III)/H 2O 2/UV, Ferrioxalate/UV/H 2O 2 and Fe(III)/H 2O 2 have been compared. Experiments have been conducted at pH=2.3±0.1 with a batch reactor equipped with a low-pressure mercury lamp emitting mainly at 253.7 nm. Data obtained under the following experimental conditions ([H 2O 2] 0=10 −3 M, [Diuron] 0=5×10 −5 M and [Fe(III)] 0=10 −3 M) have shown that rates of Diuron oxidation were higher with the systems Fe(III)/H 2O 2/UV and Ferrioxalate/UV/H 2O 2 than with Fe(III)/UV and Fe(III)/H 2O 2. On the other hand, Fe(III)/UV was found to be very efficient in mineralization of Diuron solution in comparison to direct UV photolysis. The experimental results showed that radical OH is the major pathway in the process of Diuron degradation.