The Fate of Aniline after a Photo-Fenton Reaction in an Aqueous System Containing Iron(III), Humic Acid, and Hydrogen Peroxide

The degradation of aniline (ArNH 2 ) was facilitated by light irradiation (λ > 370 nm) of an aqueous solution, which contained Fe(III), humic acid (HA), and H 2 O 2 . The consumption of H 2 O 2 and the reduction of Fe(III) to Fe(II) was consistent with the degradation of ArNH 2 via the photo-Fenton reaction, accompanied by the generation of hydroxyl radicals (HO • ). HPLC analysis of the reaction mixture indicated the presence of p -aminophenol, p -hydroquinone, and maleic and fumaric acids and the simultaneous release of NH 4 + ion. However, the sum of the product concentrations, as determined by HPLC after the reaction, was much smaller than the ArNH 2 concentration added initially. This can be attributed to the majority of the ArNH 2 being incorporated into the polymeric structure in the HA after the reaction. The 15 N NMR and pyrolysis-GC/MS studies indicated that, after the reaction, ArNH 2 formed covalent bonds with quinone and the vinyl carbons in the HA, to form anilino-compounds, such as anilinoquinone and enaminone.