Electrochemical degradation of phenol using electrodes of Ti/RuO2-Pt and Ti/IrO2-Pt

Electrochemical degradation of phenol was evaluated at two typical anodes, Ti/RuO2-Pt and Ti/IrO2-Pt, for being a treatment method in toxic aromatic compounds. The influences of current density, dosage of NaCl, initial phenol concentration on electrochemical phenol degradation were investigated. It was found that Ti/RuO2-Pt anode had a higher oxygen evolution potential than Ti/IrO2-Pt anode, which will increase the current efficiency for electrochemical degradation, and the instantaneous current efficiency (ICE) was relatively higher at the initial time during phenol electrolysis. HOCl formed during electrolysis would play an important role on the oxidation of phenol. For the Ti/RuO2-Pt anode, phenol concentration decreased from around 8 mg/L to zero after 30 min of electrolysis with 0.3 g/L NaCl as supporting electrolyte at the current density of 10 mA/cm2. Although phenol could be completely electrochemical degraded at both Ti/RuO2-Pt and Ti/IrO2-Pt anodes, phenol degradation was slower at the Ti/IrO2-Pt anode than at the Ti/RuO2-Pt anode due to the fact that passivation was to be found at the Ti/IrO2-Pt anode.