Performance of carbon black-slurry electrodes for 4-chlorophenol oxidation

The degradation of 4-chlorophenol (4-CP) by electrochemical oxidation in the presence of carbon black (CB) was studied in a laboratory reactor. This reactor consisted of a stack of Ti/Pt electrodes. After the mixing of the solution to be treated with CB, the slurry electrode thus obtained flows through the electrode grids. The reaction pathways and kinetics were studied by means of high performance liquid chromatography coupled with a UV detection, ionic chromatography coupled with a conductimetric detection and gaseous chromatography coupled with mass spectrometry. The reaction pathways were thus determined: after the C-Cl bond breaking, phenol and chloride ions were detected in the solution. The formation of 2-chlorophenol was also detected. The influence of the amount of CB used on the degradation yield of 4-CP was also studied. The full mineralisation of 4-CP could be reached if CB was present in a sufficient amount and, in this case, no chlorine was detected. (C) 1998 Elsevier Science Ltd. All rights reserved.