Chemical Engineering Journal, Vol.197, 306-313, 2012
Natural graphite tailings as heterogeneous Fenton catalyst for the decolorization of rhodamine B
A heterogeneous Fenton decolorization process of rhodamine B in aqueous solution promoted by graphite tailing (GT) was developed. For the first time, GT was used as an initiator for the Fenton reaction. The GT used in this study was characterized by X-ray diffraction (XRD), energy dispersive spectrometry (EDS) and Brunauer-Emmett-Teller (BET) method. The mesoporous structure of the GT made it as an absorbent and the encapsulated Fe2O3 in GT was able to initiate the Fenton reaction. The effects of the initial concentration of the dye, the initial concentration of H2O2, catalyst dosage, reaction temperature, stirring speed, particle size of catalyst and the pH value were determined. The results showed that the increase of catalyst dosage, initial concentration of H2O2, reaction temperature and stirring speed favor the increase of decolorization rate. The increase of initial concentration of the dye and the particle size of catalyst lead to the decrease of decolorization rate and the optimum pH was the original pH of rhodamine B solution. Under the optimal condition, the decolorization and TOC removal rates were 93.39% and 49.02% respectively after 240 min treatment. The release of the iron ion from GT is very little and the intermediates of rhodamine B degradation will not cause the wavelength shift of rhodamine B. The kinetic results showed that the decolorization and degradation of rhodamine B obeyed the pseudo-first order equation. (C) 2012 Elsevier B.V. All rights reserved.