title: Electrochemical oxidation of 2,4,5-trichlorophenoxyacetic acid by metal-oxide-coated Ti electrodes.
abstract: Electrochemical oxidation of 2,4,5-trichlorophenoxyacetic acid (2,4,5-T) over metal-oxide-coated Ti anodes, i.e., Ti/SnO2-Sb/Ce-PbO2, Ti/SnO2-Sb and Ti/RuO2, was examined. The degradation efficiency of over 90% was attained at 20 min at different initial concentrations (0.5-20 mg L(-1)) and initial pH values (3.1-11.2). The degradation efficiencies of 2,4,5-T on Ti/SnO2-Sb/Ce-PbO2, Ti/SnO2-Sb and Ti/RuO2 anodes were higher than 99.9%, 97.2% and 91.5% at 30 min, respectively, and the respective total organic carbon removal ratios were 65.7%, 54.6% and 37.2%. The electrochemical degradation of 2,4,5-T in aqueous solution followed pseudo-first-order kinetics. The compounds, i.e., 2,5-dichlorohydroquinone and 2,5-dihydroxy-p-benzoquinone, have been identified as the main aromatic intermediates by liquid chromatography-mass spectrometry. The results showed that the energy efficiencies of 2,4,5-T (20 mg L(-1)) degradation with Ti/SnO2-Sb/Ce-PbO2 anode at the optimal current densities from 2 to 16 mA cm(-2) ranged from 8.21 to 18.73 kWh m(-3).
authors.affiliation: State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing 100875, PR China.
authors.forename: Dusmant
authors.initials: D
authors.lastname: Maharana
authors.affiliation: State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing 100875, PR China.
authors.forename: Zesheng
authors.initials: Z
authors.lastname: Xu
authors.affiliation: State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing 100875, PR China. Electronic address: junfengn@bnu.edu.cn.
authors.forename: Junfeng
authors.initials: J
authors.lastname: Niu
authors.affiliation: Wastewater Technology Division, CSIR, National Environmental Engineering Research Institute, Nagpur, Maharashtra 440020, India.
authors.forename: Neti Nageswara
authors.initials: NN
authors.lastname: Rao
mesh_terms: D015085:2,4,5-Trichlorophenoxyacetic Acid / Q000737:chemistry*; D016227:Benzoquinones; D004566:Electrodes; D007700:Kinetics; D010084:Oxidation-Reduction; D010087:Oxides / Q000737:chemistry; D014025:Titanium / Q000737:chemistry*; D014865:Waste Disposal, Fluid / Q000379:methods; D014874:Water Pollutants, Chemical / Q000737:chemistry*; D018508:Water Purification / Q000379:methods
chemical_list: D016227:Benzoquinones; D010087:Oxides; D014874:Water Pollutants, Chemical; C004532:quinone; D015085:2,4,5-Trichlorophenoxyacetic Acid; D014025:Titanium
keywords: 2,4,5-Trichlorophenoxyacetic acid; Electrochemical oxidation; Energy efficiency; Ti electrodes