Photocatalytically-assisted electrooxidation of herbicide fenuron using a new bifunctional electrode PbO 2 /SnO 2 -Sb 2 O 3 /Ti//Ti/TiO 2 .

The degradation of the herbicide fenuron was investigated using a new porous bifunctional electrode where the electrooxidation takes place on one side and the photocatalysis on the other side. The characterization of the synthetized bifunctional electrode (PbO2 /SnO2 -Sb2 O3 /Ti//Ti/TiO2 ) was performed by scanning electron microscopy, energy dispersive X-ray spectrometry and X-ray diffraction analysis and showed that the anodic side (Ti/SnO2 -Sb2 O3 /PbO2 ) is covered with a tetragonal β-PbO2 film and that the photocatalytic side (Ti/TiO2 ) consists of an anatase phase of TiO2 . The single application of electrooxidation achieved 87.8% fenuron degradation and 84.1% chemical oxygen demand (COD) removal while heterogeneous photocatalysis resulted in only 59.2% and 39.7% fenuron concentration decay and COD removal, respectively. On the other hand, the photocatalytically-assisted electrooxidation (photo-electrooxidation) performed on the bifunctional electrode provided higher performances of fenuron degradation (97.5%) and mineralization (97.4%). Investigation of operating parameters highlighted the positive effect of increase in current density. Conversely, an increase in fenuron concentration led to a decrease in degradation rate and COD removal. It was also found that the COD removal and mineralization efficiency are higher in a neutral medium.