title: Fe@Fe2O3 core-shell nanowires enhanced Fenton oxidation by accelerating the Fe(III)/Fe(II) cycles.
abstract: In this study we demonstrate Fe@Fe2O3 core-shell nanowires can improve Fenton oxidation efficiency by two times with rhodamine B as a model pollutant at pH > 4. Active species trapping experiments revealed that the rhodamine B oxidation enhancement was attributed to molecular oxygen activation induced by Fe@Fe2O3 core-shell nanowires. The molecular oxygen activation process could generate superoxide radicals to assist iron core for the reduction of ferric ions to accelerate the Fe(III)/Fe(II) cycles, which favored the H2O2 decomposition to produce more hydroxyl radicals for the rhodamine B oxidation. The combination of Fe@Fe2O3 core-shell nanowires and ferrous ions (Fe@Fe2O3/Fe(2+)) offered a superior Fenton catalyst to decompose H2O2 for producing OH. We employed benzoic acid as a probe reagent to check the generation of OH and found the OH generation rate of Fe@Fe2O3/Fe(2+) was 2-4 orders of magnitude larger than those of commonly used iron based Fenton catalysts and 38 times that of Fe(2+). The reusability and the stability of Fe@Fe2O3 core-shell nanowires were studied. Total organic carbon and ion chromatography analyses revealed the mineralization of rhodamine B and the releasing of nitrate ions. Gas chromatograph-mass spectrometry was used to investigate the degradation intermediates to propose the possible rhodamine B Fenton oxidation pathway in the presence of Fe@Fe2O3 nanowires. This study not only provides a new Fenton oxidation system for pollutant control, but also widen the application of molecular oxygen activation induced by nanoscale zero valent iron.
authors.affiliation: Key Laboratory of Pesticide & Chemical Biology of Ministry of Education, Institute of Environmental Chemistry, College of Chemistry, Central China Normal University, Wuhan 430079, People's Republic of China.
authors.forename: Jingu
authors.initials: J
authors.lastname: Shi
authors.affiliation: Key Laboratory of Pesticide & Chemical Biology of Ministry of Education, Institute of Environmental Chemistry, College of Chemistry, Central China Normal University, Wuhan 430079, People's Republic of China. Electronic address: jennifer.ai@mail.ccnu.edu.cn.
authors.forename: Zhihui
authors.initials: Z
authors.lastname: Ai
authors.affiliation: Key Laboratory of Pesticide & Chemical Biology of Ministry of Education, Institute of Environmental Chemistry, College of Chemistry, Central China Normal University, Wuhan 430079, People's Republic of China. Electronic address: zhanglz@mail.ccnu.edu.cn.
authors.forename: Lizhi
authors.initials: L
authors.lastname: Zhang
mesh_terms: D005290:Ferric Compounds / Q000737:chemistry*; D015394:Molecular Structure; D053770:Nanowires / Q000737:chemistry*; D010084:Oxidation-Reduction; D012235:Rhodamines; D014874:Water Pollutants, Chemical; D018508:Water Purification / Q000379:methods*
chemical_list: D005290:Ferric Compounds; D012235:Rhodamines; D014874:Water Pollutants, Chemical; C029773:rhodamine B
keywords: Fe@Fe(2)O(3) nanowires; Fenton oxidation; Iron cycling; Molecular oxygen activation; Rhodamine B