화학공학소재연구정보센터
Applied Catalysis B: Environmental, Vol.89, No.3-4, 432-440, 2009
Adsorption and oxidation of PCP on the surface of magnetite: Kinetic experiments and spectroscopic investigations
The oxidation of pentachlorophenol (PCP) on the Surface of magnetite used as heterogeneous catalyst has been investigated under various experimental conditions (initial substrate concentration, H2O2 dose, solid loading and temperature) at neutral pH and correlated with the adsorption behavior. The surface reactivity of magnetite Was evaluated by conducting the kinetic study of both H2O2 decomposition and PCP oxidation experiments. The occurrence of the optimum values of H2O2 and magnetite concentrations for the effective degradation of PCP could be explained by the scavenging reactions with H2O2 or iron oxide surface. The surface interactions with PCP in the absence and the presence of oxidant call be well described by Langmuir and Langmuir-Hinshelwood models, respectively. All batch experiments indicate that Fenton-like oxidation of PCP was controlled by surface mechanism reaction and the species compete with each other for adsorption on a fixed number of surface active sites. The apparent degradation rate was dominated by the rate of intrinsic chemical reactions on the oxide surface rather than the rate of mass transfer. Raman analysis suggested that the sorbed PCP was removed form magnetite surface at the first stage of oxidation reaction. The mineralization determined by TOC abatement was completed after 7 d, while total dechlorination was achieved at 4 d treatment time. The first reaction of PCP oxidation should be the dechlorination since 90% of chloride was formed at the first 30 h corresponding to the total disappearance of parent compound. All X-ray powder diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Mossbauer spectroscopy and chemical analyses showed that the magnetite catalyst exhibited low iron leaching, good structural stability and no loss of performance in second reaction cycle. (C) 2009 Elsevier B.V. All rights reserved.