Degradation of humic acid via peroxymonosulfate activation by FeCo2O4 nanoparticles supported on modified coal gangue

[Display omitted] •FeCo2O4/modified coal gangue catalysts (FC-MCG) were successfully synthesized.•FC-MCG can efficiently activate PMS for HA degradation.•SO4·- and 1O2 were the major active ROS species for HA degradation.•The synthesized 20% FC-MCG had a good stability and a high reusability. Industrial solid waste can be used as nanoparticles potential supports to form heterogeneous catalysts for removing organic substances. Herein, coal gangue was modified by sulfuric acid pickling and high-temperature calcination, and FeCo2O4/modified coal gangue (FC-MCG) catalysts were synthesized via a citric acid combustion method. The crystal structures, surface morphology and elemental valence of the synthesized composites were investigated. The 20% FC-MCG possessed higher catalytic performance for HA degradation than other composites, achieving almost 85% degradation efficiency of HA (20 mg/L) in the presence of PMS. The fluorescence EEMs and FTIR spectra revealed the effective destruction of HA structure after reaction in the 20% FC-MCG/PMS system. Electron paramagnetic resonance (EPR) tests and quenching experiments showed that the SO4·-, •OH and 1O2 were produced in the PMS activation process. Additionally, the 20% FC-MCG catalyst still kept excellent catalytic performance after four times repeated use. This study was a meaningful exploration for conversion of industrial solid waste to high effective catalyst for wastewater treatment.