Activation of peroxymonosulfate by cobalt doped carbon nitride for gaseous VOC degradation.

[Display omitted] • Cobalt doped carbon nitride activated peroxymonosulfate effectively, achieving 97% toluene removal rate; • Doped cobalt atoms in carbon nitride significantly improved the production of reactive oxygen species; • Cobalt atoms accelerated the electron transfer during the peroxymonosulfate activation process; • Singlet oxygen was the dominant reactive oxygen species (ROS) in both the degradation and mineralization of toluene. Degradation of gaseous volatile organic compounds (VOCs) under mild conditions is a great challenge. In this work, we doped Co atoms in carbon nitride (CN) to form Co/CN (CCN) catalyst with Co-N configuration. The CCN catalyst exhibited higher toluene degradation efficiency (97 %) than that of the CN/PMS system (27 %) via peroxymonosulfate (PMS) activation, and exhibited high toluene removal efficiency (>90 %) within 7 days. Electron paramagnetic resonance (EPR) and radical quenching tests suggested that singlet oxygen (1O 2) was the dominant reactive oxygen species (ROS) in both the degradation and the mineralization of toluene. Density functional theory (DFT) study indicated that the electron transfer from Co atoms to PMS contributed to the generation of ROS. This work proposed a new perspective on the use of Co doped catalyst in liquid phase advanced oxidation processes (AOPs) for low-temperature VOCs removal technology. [ABSTRACT FROM AUTHOR]