Influence of chloride ion on electrochemical degradation of phenol in alkaline medium using bismuth doped and pure PbO2 anodes

Electrochemical method at laboratory scale for the treatment of biorefracto ry solutions with high phenol content-1000 ppm is described. Total degradat ion of phenol was obtained at alkaline pH when NaCl was present using Bi-do ped and pure lead dioxide electrodes. A filter press cell of 63 cm(2) geome tric area was used for this purpose. Measurements of chemical oxygen demand (COD), phenol, carbon monoxide, carbon dioxide, and volatile organic compo unds (VOCs) have been used to characterise the electrochemical process for phenol elimination. It is worth noting that in the absence of NaCl, the charge efficiency of CO D removal was independent of the current density in the range studied (50-1 00 mA cm(-2)). Moreover, when NaCl was present, the current efficiency for COD and phenol removal increase as the chloride concentration increases. Ch loroform was the only halocompound detected at the end of reaction. For bot h electrodes, Bi-doped and pure lead dioxide, the chloroform concentration at the end of the electrolysis decreases, working at low current densities and for low chloride concentrations. (C) 2001 Elsevier Science Ltd. All rig hts reserved.