Preparation of a carbon-based composite electrode for the purpose of electrochemical degradation of chlorinated phenols

Abstract

In this research we report a study of the overall degradation of somechlorophenol compounds using a carbon-based composite electrode, specificallydesigned for this purpose, and make a direct comparison between the rate ofdecomposition obtained by using the prepared electrode with that obtained by using acarbon rod electrode.The performance of both electrodes for the electrochemical oxidativedegradation of chlorophenols was assessed through the analysis of the degradationproducts using High Performance Liquid Chromatography (HPLC) and GasChromatography (GC). Successful chlorophenol removal was achieved at high initialconcentrations (100 ppm), and low current densities (5, 10 and 20 mA) with the use ofa carbon rod electrode.The composite electrode was prepared using activated carbon from wasteolives stones ( I ) embedded in Araldite™ a commercial cold-setting epoxy resin. Itwas shown that the greater the surface area of the electrode, and the higher thepotential applied to it, the faster the electrochemical degradation occurred. The pHwas maintained constant through the electrochemical degradation process sincechanges in pH were found to influence the reaction.The carbon-based composite electrode was found to be effective in thetreatment of aqueous samples contaminated with chlorophenols. However the removalrate depended on several parameters such as the precise chlorophenol used as thetarget contaminant, its concentration, the composition of the electrolyte solution,(including pH). The removal rate was also related to the applied potential and theelectrode "contact area" (area that is directly involved in the electrochemical process).A carbon rod electrode with a limited surface area was specially designed toallow comparison with the carbon-based composite electrode. This modified electrodewas found to be less efficient under the same electrochemical degi:adation parameters,demonstrating a removal rate of 21 % in comparison to the 60% removal rate obtainedby using a carbon-based composite electrode.

Date of Award	2004
Original language	English
Awarding Institution	Coventry University
Supervisor	Sukhvinder Phull (Supervisor) & Timothy Mason (Supervisor)