Reactivity of novel Ceria-Perovskite composites CeO2-LaMO3 (MCu, Fe) in the catalytic wet peroxidative oxidation of the new emergent pollutant 'Bisphenol F': Characterization, kinetic and mechanism studies

In the present study, ceria, pristine perovskites LaMO3 (Cu, Fe) and novel ceria-perovskite composites CeO2-LaMO3 were successfully prepared and applied as heterogeneous Fenton like-catalysts for the degradation and mineralization of a new emergent compound-bisphenol F (BPF) in aqueous solution. The catalysts were characterized by X-ray diffraction spectrometer (XRD), BET surface area determination, scanning electron microscopy (SEM), Energy Dispersive X-ray (EDS) and X-ray photoelectron spectroscopy (XPS) techniques. Catalytic bisphenol F behavior shows that the activity of pristine perovskites was improved due to the introduction of cerium. Catalytic activity in terms of TOC removal followed the order of CeO2-LaCuO3 > CeO2-LaFeO3 > LaCuO3 > LaFeO3 > CeO2 with about 83, 79, 68, 64 and 28% respectively. Only the novel composite oxide CeO2-LaCuO3 was found to be effective for Bisphenol F degradation at neutral conditions. EPR analyses and scavenging experiments revealed that BPF was mainly decomposed by the attack of (OH)-O-center dot, especially the surface-bounded (OH)-O-center dot. BPF decay followed pseudo-first-order reaction kinetics. The absolute rate constant for BPF oxidation by (OH)-O-center dot was found to 2.0910(9) M-1 s(-1), as determined by the competition kinetic method. Six stable organics intermediates were observed and five of them were identified p-benzoquinone, hydroquinone, 4-hydroxybenzaldehyde and Bis (4-hyroxyphenyl) methanol. Subsequent attack of these intermediates by (OH)-O-center dot radicals led to the formation of short chain acids: malonic, succinic, acetic, formic and oxalic acids. On the basis of the analytical results for the intermediate products and the assumption that hydroxyls radicals are the major reactive species, a plausible pathway of BPF mineralization during the heterogeneous Fenton process was proposed. Furthermore, the CeO2-LaCuO3 composite exhibited excellent long-term stability in the heterogeneous Fenton-like process. These results suggested that the novel ceria perovskite material would be a promising candidate for practical wastewater treatment. (C) 2017 Elsevier B.V. All rights reserved.