title: Decolorization of methylene blue in layered manganese oxide suspension with H2O2.
abstract: Layered birnessite-type manganese oxides (Na-OL-1) were prepared via a redox reaction involving MnO(4)(-) and Mn(2+) under markedly alkaline conditions. According to the XRD analysis, the resulting material exhibited a well-crystallized octahedral layer (OL) structure with several different phases, including β-MnOOH, α-MnOOH and γ-Mn(3)O(4). The catalyst was highly effective for the decolorization and degradation of methylene blue (MB) in the presence of H(2)O(2) at neutral pH. The tested MB was completely decolorized in Na-OL-1 suspension by the fraction dosing of H(2)O(2) (556.5mM at the beginning and then 183.8mM at 40 min). Based on the studies of electron spin resonance and the effect of radical scavengers, the (1)O(2) and O(2)(-) were the main reactive oxygen species (ROS) in the reaction. It was found that both oxygen and ROS were generated from the decomposition of H(2)O(2) in Na-OL-1 suspension, wherein the decomposition pathways were proposed. The generation of H(2)O(2) in Na-OL-1 suspension at air atmosphere indicated that the existence of multivalent manganese oxides greatly enhanced the interfacial electron transfer, leading to the high activity of Na-OL-1.
authors.affiliation: State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.
authors.forename: Lili
authors.initials: L
authors.lastname: Zhang
authors.forename: Yulun
authors.initials: Y
authors.lastname: Nie
authors.forename: Chun
authors.initials: C
authors.lastname: Hu
authors.forename: Xuexiang
authors.initials: X
authors.lastname: Hu
mesh_terms: D002384:Catalysis; D003116:Color; D052918:Environmental Restoration and Remediation / Q000379:methods; D006861:Hydrogen Peroxide / Q000737:chemistry*; D017895:Manganese Compounds / Q000138:chemical synthesis / Q000737:chemistry*; D008751:Methylene Blue / Q000737:chemistry*; D010087:Oxides / Q000138:chemical synthesis / Q000737:chemistry*; D010100:Oxygen / Q000737:chemistry; D017382:Reactive Oxygen Species / Q000737:chemistry; D013535:Suspensions / Q000737:chemistry
chemical_list: D017895:Manganese Compounds; D010087:Oxides; D017382:Reactive Oxygen Species; D013535:Suspensions; C027424:manganese oxide; D006861:Hydrogen Peroxide; D010100:Oxygen; D008751:Methylene Blue