Phenol degradation was studied in a novel electrochemical system with TiO2/activated carbon fiber as anode and graphite as cathode. The removal of phenol was investigated in terms of various parameters namely: cathode and anode gap, pH, current density, initial phenol concentration and addition of Na2SO4. At the same time, percentages of phenol degradation and COD removal were observed at different electrodes. The results showed that, at the phenol concentration of 100 mg/L, cathode and anode gap of 2 cm, current density of 7.14 mA/cm2, solution pH 6.20 and 0.0750 mol/L Na2SO4, degradation of 83.26% phenol and removal of 47.03% COD after 1 h electrolysis can be achieved with TiO2/ACF–graphite as anode, while 67.72% phenol and 35.78% COD achieved with ACF/graphite as anode. Under the same conditions mentioned above, no phenol can be detected in 105 min at the initial phenol concentration of 10 mg/L with TiO2/ACF–graphite as anode. The electrochemical oxidation reaction of phenol obeyed pseudo-first order kinetic. The mass adsorbed hydroxyl radicals were generated on the TiO2/ACF electrode due to its three-dimensional space, high oxygen evolution potential and the catalysis of TiO2. With the formation of hydroxyl radicals, the phenol was oxidized to produce hydroquinone, pyrocatechol and benzoquinone during electrochemical process. The concentrations of these three aromatic compounds achieve peak values after 3 h, 2 h and 1 h, respectively. Then, they gradually diminished and were degraded to form ring-opened products such as formic and maleic acids, which were oxidized to CO2 and H2O finally.
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