Electrochemical oxidation of phenol using boron-doped diamond electrodes
The oxidation of phenol is compared for two different boron doped diamond (BDD) electrodes; a niobium supported BDD planar electrode and a BDD coated Ti mesh. Raman spectroscopy and cyclic voltammetry were used to compare the two electrodes. Continuous oxidation of phenol utilized a flow cell configuration that circulated a fixed volume of solution, scaled to the electrode area, with an initial concentration of 10 mM phenol in 0.1M H2SO4. The conversion of phenol to CO2 was monitored by scheduled collection of aliquots and subsequent total organic carbon (TOC) analysis. The two electrodes were found to have similar conversion rates, with the total carbon decreasing from ~1% to <0.1%. Treatment of a more concentrated solution, 87 mM phenol in 0.1M H2SO4, was examined for the planar electrode and resulted in greater efficiency, which was attributed to greater localization between reactants and hydroxyl radicals in the kinetic limited regime.