Electrochemical oxidation of 4-chlorophenol for wastewater treatment - Definition of normalized current efficiency (phi)

The electrochemical behavior of lead dioxide and synthetic boron-doped diam ond thin film electrodes (BDDs) has been studied in acid media containing 4 -chlorophenol (4-CP) by bulk electrolysis under different experimental cond itions. In order to quantify the electrochemical activity of a given electr ode, for the electrochemical oxidation of organic compounds (4-CP), the cur rent efficiency of the anodic oxidation has been normalized taking into con sideration mass-transport limitations. The normalized current efficiency (p hi) has been defined as the ratio between the current efficiency of the inv estigated anode to the current efficiency of an ideal anode which has a ver y fast oxidation rate, resulting in a complete combustion of organics to ca rbon dioxide. The results have shown that even if the complete combustion o f 4-chlorophenol has been achieved at both lead dioxide and boron-doped dia mond anodes, the latter give higher f. The difference in reactivity of the electrogenerated hydroxyl radicals on the anode surface, has been proposed to explain the high f values obtained using boron-doped diamond anodes. (C) 2001 The Electrochemical Society.