title: Heterogeneous electro-Fenton oxidation of azo dye methyl orange catalyzed by magnetic Fe3O4 nanoparticles.
abstract: Azo dye methyl orange (MO) degradation by heterogeneous electro-Fenton (EF) with a magnetic nano-Fe3O4 catalyst was investigated. In this study, Fe3O4 was synthesized by a coprecipitation method and characterized by X-ray diffraction and scanning electron microscopy. The influences of the main operating parameters such as current density, pH, catalyst dosage and aeration rate were studied. The results revealed that higher current density, catalyst dosage and aeration rate facilitated the degradation of MO, whereas the degradation efficiency of MO was decreased with an increase in the initial pH. After 90 min EF process, the volume of 500 mL, the initial concentration of 50 mg L(-1) MO solution could be degraded by 86.6% with the addition of 1 g L(-1) Fe3O4 under the current density of 10 mA cm(-2) and pH 3, compared with 69.5% for the electrolytic process alone. Meanwhile, a total organic carbon removal of 32% was obtained, up to 35.5 mg L(-1) accumulated H2O2 and less than 3.5 mg L(-1) Fe leaching were detected. Moreover, based on the results of natural bond orbital (at B3LYP/6-311G (d, p)) and liquid chromatograph-triple quadrupole mass spectrometer analysis, nine intermediates were identified and the proposed degradation pathways were investigated.
authors.affiliation: State Key Laboratory of Pollution Control and Resources Reuse, School of the Environment, Nanjing University, Nanjing 210046, China E-mail: sybnju@163.com.
authors.forename: Hao
authors.initials: H
authors.lastname: Jiang
authors.affiliation: State Key Laboratory of Pollution Control and Resources Reuse, School of the Environment, Nanjing University, Nanjing 210046, China E-mail: sybnju@163.com.
authors.forename: Yabing
authors.initials: Y
authors.lastname: Sun
authors.affiliation: School of Civil and Hydraulic Engineering, Hefei University of Technology, Hefei 230009, China and State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering, Hohai University, Nanjing 210098, China.
authors.forename: Jingwei
authors.initials: J
authors.lastname: Feng
authors.affiliation: State Key Laboratory of Pollution Control and Resources Reuse, School of the Environment, Nanjing University, Nanjing 210046, China E-mail: sybnju@163.com.
authors.forename: Jian
authors.initials: J
authors.lastname: Wang
mesh_terms: D001391:Azo Compounds / Q000737:chemistry*; D002384:Catalysis; D004396:Coloring Agents; D004572:Electrolysis; D052203:Ferrosoferric Oxide / Q000737:chemistry*; D006861:Hydrogen Peroxide / Q000737:chemistry*; D053768:Metal Nanoparticles / Q000737:chemistry*; D008855:Microscopy, Electron, Scanning; D010084:Oxidation-Reduction; D014874:Water Pollutants, Chemical / Q000737:chemistry*; D018508:Water Purification / Q000379:methods; D014961:X-Ray Diffraction
chemical_list: D001391:Azo Compounds; D004396:Coloring Agents; D014874:Water Pollutants, Chemical; C100258:methyl orange; D006861:Hydrogen Peroxide; D052203:Ferrosoferric Oxide