Indirect electrochemical oxidation of pentachlorophenol in the presence of different halides: behavior and mechanism

AbstractIndirect electrochemical oxidation (EO) of pentachlorophenol (PCP) wastewater was carried out in the presence of different halides through the electrogeneration of active halide (AH). The EO effect and electrochemical behaviors of PCP under different conditions are present in this paper. The cyclic voltammetry (CV) curves indicated higher electrogeneration efficiency of active halogen in NaBr solution. Chronoamperometric response proved the formation of passivating polymer on anode surface. The conversion rate of PCP was distinctly different for different halides following the order Br− > Cl− > F− > I−. The proper oxidation potential of Br−to active bromine led to the optimal electrooxidation effect of Br−. With the rise of temperature the reaction rate decreased at first from 30 to 45 °C and then increased from 45 to 60 °C. The complicated variation of PCP conversion on rising temperature was depicted by the electrochemical measurements and a mathematic model.