title: Magnetic nanoscaled Fe3O4/CeO2 composite as an efficient Fenton-like heterogeneous catalyst for degradation of 4-chlorophenol.
abstract: Magnetic nanoscaled Fe(3)O(4)/CeO(2) composite was prepared by the impregnation method and characterized as a heterogeneous Fenton-like catalyst for 4-chlorophenol (4-CP) degradation. The catalytic activity was evaluated in view of the effects of various processes, pH value, catalyst addition, hydrogen peroxide (H(2)O(2)) concentration, and temperature, and the pseudo-first-order kinetic constant of 0.11 min(-1) was obtained for 4-CP degradation at 30 °C and pH 3.0 with 30 mM H(2)O(2), 2.0 g L(-1) Fe(3)O(4)/CeO(2), and 0.78 mM 4-CP. The high utilization efficiency of H(2)O(2), calculated as 79.2%, showed a promising application of the catalyst in the oxidative degradation of organic pollutants. The reusability of Fe(3)O(4)/CeO(2) composite was also investigated after six successive runs. On the basis of the results of metal leaching, the effects of radical scavengers, intermediates determination, and X-ray photoelectron spectroscopic (XPS) analysis, the dissolution of Fe(3)O(4) facilitated by CeO(2) played a significant role, and 4-CP was decomposed mainly by the attack of hydroxyl radicals (•OH), including surface-bound •OH(ads) generated by the reaction of Fe(2+) and Ce(3+) species with H(2)O(2) on the catalyst surface, and •OH(free) in the bulk solution mainly attributed to the leaching of Fe.
authors.affiliation: Laboratory of Environmental Technology, INET, Tsinghua University, Beijing, People's Republic of China.
authors.forename: Lejin
authors.initials: L
authors.lastname: Xu
authors.forename: Jianlong
authors.initials: J
authors.lastname: Wang
mesh_terms: D002384:Catalysis; D002563:Cerium / Q000737:chemistry*; D002733:Chlorophenols / Q000302:isolation & purification*; D006861:Hydrogen Peroxide / Q000737:chemistry*; D007501:Iron / Q000737:chemistry*; D058185:Magnetite Nanoparticles / Q000737:chemistry*; D010084:Oxidation-Reduction; D014874:Water Pollutants, Chemical / Q000302:isolation & purification*
chemical_list: D002733:Chlorophenols; C045076:Fenton's reagent; D058185:Magnetite Nanoparticles; D014874:Water Pollutants, Chemical; D002563:Cerium; C029107:4-chlorophenol; C030583:ceric oxide; D006861:Hydrogen Peroxide; D007501:Iron