科研之友
微信
新浪微博
Facebook
分享链接
摘要
The oxidation of pentachlorophenol (PCP) on the Surface of magnetite used as heterogeneous catalyst has been investigated under various experimental conditions (initial substrate concentration, H(2)O(2) 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 H(2)O(2) decomposition and PCP oxidation experiments. The occurrence of the optimum values of H(2)O(2) and magnetite concentrations for the effective degradation of PCP could be explained by the scavenging reactions with H(2)O(2) 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.
- 出版日期2009-7-15
- 单位武汉大学
