DEGRADATION OF NITROBENZENE AND NITROPHENOLS BY MEANS OF ADVANCED OXIDATION PROCESSES IN A HOMOGENEOUS PHASE - PHOTOLYSIS IN THE PRESENCE OF HYDROGEN-PEROXIDE VERSUS THE FENTON REACTION

Degradation reactions of aqueous nitrobenzene (I), 2-nitrophenol (II) , and 2,4-dinitrophenol (III) by means of direct photolysis, and the photolysis in the presence of hydrogen peroxide, were investigated. The results are compared with those for 4-nitrophenol (IV) and the Fenton reaction of the compounds. I-IV, reported elsewhere. No effect was observed during direct photolysis, while photoirradiations in the presence of hydrogen peroxide resulted in a significant degradation of the pollutants. The rates of the oxidations of the compounds I-IV depend on their electronic structures in the ground and excited states. The mechanisms of the reactions as well as advantages of both processes are discussed. The Fenton reaction is suggested as a preferred method for elimination of I-IV from waters and wastewaters.