Modified goethites as catalyst for oxidation of quinoline: Evidence of heterogeneous Fenton process

A heterogeneous Fenton-like reaction occurring on the thermally modified surface of a synthetic iron oxide previously treated with a H2 stream was investigated. The quinoline decomposition, used as an organic substrate model, was monitored with electrospray ionization mass spectrometry. Quinoline was found to be oxidized through a successive hydroxylation mechanism. These results strongly suggest that highly reactive hydroxyl radicals, generated during the reaction involving H2O2 on the catalysts surface, respond for this oxidation, and confirm that the material is an efficient heterogeneous Fenton-like catalyst. Theoretical quantum mechanics calculations, by the density functional theory (DFT), were carried out in order to understand the basic molecular degradation steps for quinoline decomposition mechanism on this H2-treated goethite (αFeOOH) surface.

Graphical abstractIn the present work, the reactivity of a heterogeneous Fenton system based on thermally treated goethite, particularly focusing on the effect of surface Fe2+ sites on the iron oxide particles to degrade quinoline in aqueous medium was studied. The reactions were monitored by using an electrospray ion source with an Agilent ion trap mass spectrometer (ESI-MS). The chemical mechanism was modeled with theoretical calculations. Figure optionsDownload full-size imageDownload as PowerPoint slide