A high activity of Ti/SnO2-Sb electrode in the electrochemical degradation of 2,4-dichlorophenol in aqueous solution.

Electrochemical degradation of 2,4-dichlorophenol (2,4-DCP) in aqueous solution was investigated over Ti/SnO2-Sb anode. The factors influencing the degradation rate, such as applied current density (2-40 mA/cm2), pH (3-11) and initial concentration (5-200 mg/L) were evaluated. The degradation of 2,4-DCP followed apparent pseudo first-order kinetics. The degradation ratio on Ti/SnO2-Sb anode attained > 99.9% after 20 min of electrolysis at initial 5-200 mg/L concentrations at a constant current density of 30 mA/cm2 with a 10 mmol/L sodium sulphate (Na2SO4) supporting electrolyte solution. The results showed that 2,4-DCP (100 mg/L) degradation and total organic carbon (TOC) removal ratio achieved 99.9% and 92.8%, respectively, at the optimal conditions after 30 min electrolysis. Under this condition, the degradation rate constant (k) and the degradation half-life (t1/2) were 0.21 min- and (2.8 +/- 0.2) min, respectively. Mainly carboxylic acids (propanoic acid, maleic acid, propanedioic acid, acetic acid and oxalic acid) were detected as intermediates. The energy efficiencies for 2,4-DCP degradation (5-200 mg/L) with Ti/SnO2-Sb anode ranged from 0.672 to 1.602 g/kWh. The Ti/SnO2-Sb anode with a high activity to rapid organic oxidation could be employed to degrade chlorophenols, particularly 2,4-DCP in wastewater.