Electrochemical oxidation of ofloxacin using a TiO2-based SnO2-Sb/polytetrafluoroethylene resin-PbO2 electrode: Reaction kinetics and mass transfer impact
| Autor: | Duo Li, Ruzhen Xie, Wenju Jiang, Junfeng Niu, Peizhe Sun, Lawrence A. Bottomley, John C. Crittenden, Yongsheng Chen, Xiaoyang Meng |
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| Rok vydání: | 2017 |
| Předmět: |
Mass transfer coefficient
Chemistry Process Chemistry and Technology Inorganic chemistry Oxygen evolution 02 engineering and technology Electrolyte 010501 environmental sciences Overpotential 021001 nanoscience & nanotechnology Electrochemistry 01 natural sciences Catalysis Mass transfer Electrode Organic chemistry 0210 nano-technology Plug flow reactor model 0105 earth and related environmental sciences General Environmental Science |
| Zdroj: | Applied Catalysis B: Environmental. 203:515-525 |
| ISSN: | 0926-3373 |
| Popis: | 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-Sb/polytetrafluroethylene resin (FR)-PbO2 electrode that was based on TiO2 nanotubes. 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, kWh/m3) 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 ) 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 Ω (between 0 and 1). Our experiments and calculations indicated that the mass transfer reduced oxidation rate by more than 55% (Ω |
| Databáze: | OpenAIRE |
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