Photocatalytic performance of granite waste in the decolorization and degradation of Reactive Orange 122

Publication date: June 2019Source: Journal of Environmental Chemical Engineering, Volume 7, Issue 3Author(s): S.A.D. Ferreira, J.F. Donadia, G.R. Gonçalves, A.L. Teixeira, M.B.J. G. Freitas, A.A.R. Fernandes, M.F.F. LelisAbstractThe photocatalytic activity of granite waste (GW), an iron-rich material, was evaluated by the decolorization and degradation of Reactive Orange 122 (RO122) in the presence of H2O2 by solar photo-Fenton. X-ray powder diffraction (XRD), 57Fe Mössbauer spectroscopy, and scanning electron microscopy (SEM) confirmed the presence of magnetite (Fe3O4), hematite (α-Fe2O3), and zero-valent iron (α-Fe0) in GW. GW showed great potential in the decolorization and degradation of RO122, reaching 100.0% efficiency at pH 3.0 and 91.0% efficiency at pH 6.5 under the best experimental condition (20 mg of waste and 3.0 mL of 0.040 mol L−1 H2O2). The use of solar irradiation made the method more environmentally friendly and economic. RO122 degradation was best fitted to a first-order kinetic model (k = 0.0684 min−1 for pH 3.0 and k = 0.0467 min−1 for pH 6.5). Dye solutions were completely decolorized and effectively mineralized, achieving a 68.7% total organic carbon (TOC) removal at pH 3.0 and a 29.2% TOC removal at pH 6.5. The results show that GW is a highly efficient heterogeneous photo-Fenton catalyst.
Source: Journal of Environmental Chemical Engineering - Category: Chemistry Source Type: research