Electrochemical fabrication of polyaniline films deposited on graphene-loaded electrodes for •OH production and perfluorooctanoic acid degradation

Abstract

The present study describes the coating of modified graphite felt (GF) with graphene (GE) and polyaniline (PANI). GF was doped with nitrogen atoms by a series of modification and electrolyticdeposition. Tests of different types of N content and cathodic catalytic oxidation performance confirmed that the graphite N introduction promoted the production of H2O2 in the 2e- process. Pyridine N catalyzed the H2O2 decomposition to produce •OH. The amount of H2O2 produced by GF, GF-GE, and GF-GE@PANI system was 11 mg L-1, 70 mg L-1, and 180 mg L-1, respectively. The doping of graphene increased H2O2 yield, and the electrolyticdeposition of PANI converted H2O2 to •OH rapidly. It was proved that the N atom provided by graphene was graphite N, which was the active catalytic site for the production of H2O2. The perfluorooctanoic acid (PFOA) removal at 180 min was 24.1% and 49.8% in the GF and GF-GE systems, respectively. The GF-GE@PANI system achieved 100% PFOA removal within 160 min. It was demonstrated that the enrichment of PANI with pyridine N provided many active sites for improving the conversion of H2O2 to •OH and in-situ degrading organic pollutants, offering an alternative for wastewater treatment.