Primary mechanism in the degradation of 4-octylphenol photoinduced by Fe(III) in water-acetonitrile solution

The degradation of 4-octylphenol (4-OP), a toxic and persistent product in the environment, photoinduced by Fe(III) has been investigated in water/acetonitrile solution (95/5 by volume). The initial rate of 4-OP degradation depends on the irradiation wavelength and on the initial concentration of Fe(OH)(2+), the monomeric species present in our experimental conditions. Several photoproducts have been identified among them 4-(1,1,3,3-tetramethylbutyl)pyrocatechol. The formation of octylphenoxyl radical was observed by fast kinetics as a result of the quenching reaction between Fe(III) species in the excited state and 4-OP. For longer irradiation times, regeneration of the monomeric species, Fe(OH)(2+), was suggested due to Fe(II) reoxidation by radicals. (C) 2000 Elsevier Science S.A. All rights reserved.