Iron–alumina synergy in the heterogeneous Fenton-type peroxidation of phenol solutions

• Published in: Chemical engineering journal (Lausanne, Switzerland : 1996) Switzerland : 1996), 2015-05, Vol.268, p.280-289
• Main Authors: di Luca, C., Ivorra, F., Massa, P., Fenoglio, R.
• Format: Article
• Language: English
• Subjects: CWHPO; Fe–Al2O3; Heterogeneous Fenton-like systems; Mesoporous alumina; Phenol
• ISSN: 1385-8947; 1873-3212
• DOI: 10.1016/j.cej.2015.01.074

[Display omitted] •Mesoporous alumina-supported Fe catalysts were developed (0.5–4% Fe).•The systems were applied in the phenol catalytic peroxidation reaction at 70°C.•A synergistic effect between Fe–Al might improve the catalytic performance.•Catalytic activity was enhanced due to high dispersion over the alumina support.•High mineralization levels (up to 80%) and efficient H2O2 consumption were reached. Highly dispersed Fe2O3/Al2O3 catalysts (0.5–4wt% Fe) were prepared by incipient wetness impregnation of iron citrate over a mesoporous alumina host. Their structural and textural properties were determined by N2 adsorption–desorption at −196°C, XRD, TEM, SEM–EDAX, Raman and XPS. The structure of the catalytic materials resulted similar to the γ-Al2O3 support, exhibiting high dispersion levels of the iron oxide active phase with a narrow pore size distribution in the range of 2–7nm and high surface areas. The capability of these systems as efficient and active Fenton-like catalysts, were further tested for the catalytic oxidation of concentrated phenol solutions (5g/L) with H2O2 at 70°C in a batch reactor. The effects of iron concentration, catalyst concentration and the nature of the support were evaluated, under adjusted sub-stoichiometric oxidant concentration. Besides the positive impact of increasing the iron loading, a synergistic effect between Fe and Al species would be possibly responsible of the improvements observed using higher iron dispersions and/or support concentrations. The catalytic performance of these alumina-based catalysts resulted very promissory as they yielded: total phenol abatement, high mineralization levels (up to a maximum of 80%) and high oxidant consumption efficiencies (between 80% and 96%).