Modified diatomites for Fenton-like oxidation of phenol

Identifier:  imarina:3661915

Handle: https://hdl.handle.net/20.500.11797/imarina3661915

Authors:  Inchaurrondo, N; Ramos, CP; Zerjav, G; Font, J; Pintar, A; Haure, P

Abstract:
Raw diatomites were modified by acid or base treatments; addition of Fe or Cu species through the incipient wet impregnation method (IWI) and calcination at 700°C. Samples were characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM-EDX), ossbauer spectroscopy, point of zero charge (PZC), pyridine temperature programme desorption (TPD), themogravimetric analysis (TGA) and BET surface area determination. According to characterization results, four samples were selected: simply calcined Diatom (D), iron added (Fe-D), acid treated Fe reimpregnated (H-Fe-D) and copper added (Cu/Fe-D). Materials were tested as catalysts for the peroxidation of phenol solutions (1000 mg/L) in a batch laboratory reactor, at different operating conditions in 5 hours tests. D, Fe-D and H-Fe-D samples allowed complete phenol removal under all the operating range studied. At optimum conditions, TOC conversions of 50-55 % were obtained. Metal ions added through the IWI procedure resulted more labile than metal present originally. The acidic treatment favoured the initiation of the reaction showing a reduction of the induction period at almost neutral initial pH. The Fe-D catalyst exhibited poor performance, lower reactions rates and higher Fe leaching. Conversely, high TOC conversions (80 %) were achieved with Cu/Fe-D, however, Cu leaching was excessive (12.7 %). D and H-Fe-D samples were used in consecutive runs (up to 20 h) maintaining phenol conversion and TOC reduction. Overall, a good performance was obtained, even comparable to more sophisticated Fe catalysts.