Electrochemical degradation of p-nitrophenol on carbon nanotube and Ce-modified-PbO2 electrode

Modification of PbO2 electrode was carried out by carbon nanotube (CNT) and Ce co-deposition. The surface morphology and crystal structure of CNT and Ce modified PbO2 (CNT-Ce-PbO2) electrode was characterized by scanning electronic microscopy (SEM), transmission electron microscope (TEM), X-ray diffraction (XRD) and Brunauer-Emmett-Teller (BET) specific surface area, respectively, and compared with pure PbO2, Ce-PbO2, and CNT-PbO2 electrodes. The results indicate that the CNT and Ce were both doped into PbO2 film and the CNT-Ce-PbO2 electrode had smaller grain size and higher specific surface area than those of other three kinds of electrodes. The electrochemical properties of electrodes were tested by linear sweep voltammetry and cyclic voltammetry, and the results show that the CNT-Ce-PbO2 electrode had higher electro-catalytic activity than pure PbO2, Ce-PbO2, and CNT-PbO2 electrodes. The accelerated lifetime tests demonstrate that the service life of CNT-Ce-PbO2 electrode was 4.76 times longer than that of pure PbO2 electrode. The CNT-Ce-PbO2 electrode was also used in electrochemical degradation of p-nitrophenol (p-NP) in aqueous solution. The degradation kinetics and mechanism of p-NP were discussed. Besides, the variation of biodegradability of p-NP degradation solution was also investigated, and the results obtained revealed a feasible combination between electrochemical oxidation and conventional bio-treatment for the treatment of p-NP wastewater.