Highly Efficient Electrochemical Oxidation of Carbamazepine Using a Novel Graphene Nanoplatelet-doped PbO₂ Electrode: Characteristics, Efficiency, and Mechanism

A novel graphene nanoplatelet (GN)-doped PbO2 electrode was fabricated and utilized to pulse electrochemical oxidize carbamazepine (CBZ) in aquesous solution. The GN-PbO2 electrode differed from a pure PbO2 electrode in that it exhibited higher surface roughness, smaller particle size, larger specific surface area, greater oxidation peak current, smaller charge transfer resistance, and higher oxygen evolution potential. After electrolysis for 90 min, 94.74% of CBZ and 45.15% of chemical oxygen demand could be removed at an initial pH of 3, pulsed frequency of 3000 Hz, current density of 20 mA cm(-2), and pulsed duty cycle of 50%. Additionally, the primary electrochemical oxidation mechanism at the GN-PbO2 anode was indirect radical oxidation and the degradation pathway of CBZ in pulsed electrochemical oxidation was investigated and clarified considering the identified intermediate products and theoretical computations. The results demonstrate that pulsed electrochemical oxidation based on GN-PbO2 electrodes is a promising approach to increasing the viability of pharmaceutical wastewater treatment by electrochemical technologies.