Efficient degradation of bisphenol A via peroxydisulfate activation using in-situ N-doped carbon nanoparticles: Structure-function relationship and reaction mechanism

A novel in-situ N-doped carbon nanoparticles (NCNs) was prepared through direct pyrolysis of N-rich polyaniline (PANI) without using external N-containing precursor and the as-prepared materials were employed as metal-free peroxydisulfate (PDS) activator for bisphenol A (BPA) degradation. The catalyst derived from PANI carbonization at 900 °C (NCNs-9) displayed the excellent catalytic activity to activate PDS, resulting in 96.0% BPA degradation efficiency within 20 min. The catalytic activity of NCNs was closely related to their structure-composition, and higher graphitic N content and larger BET surface area were beneficial to the generation of reactive oxygen species (ROS). The quenching tests and electron paramagnetic resonance (EPR) demonstrated that BPA degradation in PDS/NCNs system was accomplished via non-radical (1O2) and radical ( ·OH, SO4·−, and O2·−) pathways, in which O2·− was the main ROS. The origin of O2·− was the conversion of dissolved oxygen and the activation of PDS. The possible degradation pathways of BPA were also proposed. This study might provide inspirations to design in-situ N-doped carbon nanoparticles as the PDS activator for efficient degradation of persistent organic compound via advanced oxidation processes (AOPs).