In-situ degradation of organic pollutants by bioelectrical-Fenton reaction with a metal-free polyaniline-derived nitrogen-doped carbon nanofibre electrode

Polyaniline (PANI)-derived nitrogen-doped carbon nanofibres used as cathode electrodes in situ generate and activate H2O2 to form •OH without metal catalysts. The degradation rates of ciprofloxacin hydrochloride (CIP) and methyl orange (MO) were 99.64% and 100%, respectively, and the mineralisation rates were 54.24% and 62.56% at the modified metal-free Fenton system for microbial fuel cells (MFC-Fenton) cathode. Micropores were introduced into the electrode to provide active sites such as pyridinic N and graphitic N, which improves the electron transfer rate and redox activity, as well as exhibiting excellent power generation capacity (783.48 ± 10.52 mV and 33.57 ± 0.14 W m− 3) in comparison with a single MFC process (543.14 ± 3.56 mV and 11.02 ± 1.03 W m− 3). The degradation intermediates and mechanisms of this process were studied in detail. This study provides a new understanding of MFC-Fenton systems for removing practical organic pollutants in wastewater.