Abatement of oxalates catalyzed by Fe-silica structured surfaces via cyclic carboxylate intermediates in photo-Fenton reactions

In order to avoid excess of Fe-ions in Fenton treated wastewater, inorganic structured materials like Nafion, Nafion/silica have recently been loaded with Fe-ions to carry out immobilized Fenton photo-assisted degradation of different pollutants. In particular, novel silica/Fe structured fabrics (SiO2, B2O3, MgO, Al2O3, K2O Na2O, Fe2O3) were observed to degrade oxalates only under light irradiation showing the formation and disappearance of Fe-carboxylates and the concomitant recycling of the resulting Fe-ions back to the structured catalyst surface. In this paper, the mechanism of such an immobilized Fenton photo-assisted degradation of oxalates has been elucidated by means of advanced spectroscopic technique (i.e., infrared attenuated total reflection Fourier transform spectroscopy)