Evolution of the antibacterial activity and oxidation intermediates during the electrochemical degradation of norfloxacin in a flow cell with a PTFE-doped ß-PbO^sub 2^ anode: Critical comparison to a BDD anode

The electrochemical degradation of the antibiotic norfloxacin (NOR) was investigated using an electrodeposited polytetrafluoroethylene (PTFE)-doped β-PbO2 anode; its attained performance was compared to that of a boron-doped diamond (BDD) anode to check out a literature claim of superior performance...

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Veröffentlicht in:Electrochimica acta 2018-09, Vol.284, p.260
Hauptverfasser: Sánchez-Montes, Isaac, Neto, José R Fuzer, Silva, Bianca F, Silva, Adilson J, Aquino, José M, Rocha-Filho, Romeu C
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Sprache:eng
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Zusammenfassung:The electrochemical degradation of the antibiotic norfloxacin (NOR) was investigated using an electrodeposited polytetrafluoroethylene (PTFE)-doped β-PbO2 anode; its attained performance was compared to that of a boron-doped diamond (BDD) anode to check out a literature claim of superior performance by the former anode. The PTFE content in the electrodeposition bath was optimized to lead to a significantly extended service life of the β-PbO2 anode despite its titanium substrate. The NOR degradation electrolyses (100 mg L−1 NOR in 0.1 mol L−1 Na2SO4) were carried out in a filter-press flow cell (flow rate of 420 L h−1) using the following optimized conditions: no pH control, current density of 10 mA cm−2, and 40 °C. The electrooxidation process performance under these conditions was assessed through the evolution of the attained removals of NOR, total organic carbon (TOC), and antibacterial activity against Escherichia coli; the evolution of oxidation intermediates (aromatic compounds and carboxylic acids) was also assessed. In spite of the complete oxidation of NOR, the TOC removal attained with the PTFE-doped β-PbO2 anode was relatively low (70% after 12 h, compared to 90% after only 5 h for a Si/BDD anode). As a consequence of this inferior performance comparatively to that of a BDD anode, a higher number of aromatic intermediates was detected; these intermediates seemed to still present antibacterial activity against Escherichia coli, which lasted even after all NOR was oxidized, contrary to the case of the electrooxidation with a BDD anode. The performance of the PTFE-doped β-PbO2 anode was not superior to that of a BDD anode, i.e. the doping of the β-PbO2 film with PTFE, making it hydrophobic, does not change the oxidation power of the anode despite increasing its service life.
ISSN:0013-4686
1873-3859