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4257374 
Journal Article 
Electrochemical oxidation of ofloxacin using a TiO2-based SnO2-Sb/polytetrafluoroethylene resin-PbO2 electrode: Reaction kinetics and mass transfer impact 
Xie, R; Meng, X; Sun, P; Niu, J; Jiang, W; Bottomley, L; Li, Duo; Chen, Y; Crittenden, J 
2017 
Yes 
Applied Catalysis B: Environmental
ISSN: 0926-3373 
203 
515-525 
WOS:000390965000050 
Electrochemical Electrochemical oxidation has been proposed for the destruction of organic contaminants; however, this process is hampered by low oxidation efficiency and high energy cost. Accordingly, we developed a TiO2-based SnO2-Sbipolytetrafluroethylene resin (FR)-PbO2 electrode that was based on TiO2 nano tubes. We tested the performance of the electrode on an antibiotic, ofloxacin, and identified the major pathway of ofloxacin oxidation. We found growing TiO2 nanotubes on Ti material increased current efficiency, and the electrical efficiency per order (EE/O, kWhim(3)) for oxidation was decreased by 16.2%. Our electrode requires a large overpotential before electrons flow, which minimizes oxygen evolution, reduces hydrogen peroxide and ozone generation, and favors hydroxyl radicals (HO center dot) production. We found the electron efficiency (EE) during oxidation was as high as 88.45%. In other words, 88.45% of the electrons that flow out of the electrode cause oxidation. The effects of current density, initial concentration, pH value and electrolyte concentration were investigated. A differential column batch reactor (DCBR) was used to simulate the performance of continuous plug flow reactor and we found that the destruction of ofloxacin followed pseudo-first order model. We also. evaluated the impact of mass transfer on electrochemical performance. The effects of fluid velocity and electrode spacing on-oxidation rate were evaluated by determining the mass transfer coefficient and the effectiveness factor Omega (between 0 and 1). Our experiments and calculations indicated that the mass transfer reduced oxidation rate by more than 55% (Omega <0.45) for an electrode spacing of 1 cm at a fluid velocity of 0.033 mks. Unlike studies carried out using completely mixed batch reactor, the DCBR can simulate the flow conditions in pilot or full scale reactors; consequently, observed pseudo-first order rate constants in the DCBR can be used for preliminary design. (C) 2016 Elsevier B.V. All rights reserved. 
Electrochemical oxidation; Ofloxacin; Hydroxyl radicals (HO center dot); Mass transfer; Effectiveness factor Omega