Synthesis of single atom cobalt dispersed on 2D carbon nanoplate and degradation of acetaminophen by peroxymonosulfate activation

Single Co atoms dispersed on 2D carbon nanoplate catalyst (SA-Co CNP) was synthesized successfully by a facile one-step method. Its morphology and structure were characterized by SEM, TEM, HAADF-STEM, XRD and XPS. Results showed that SA-Co CNP exbibit uniform two-dimensional nanoplate structure with several micrometers. Co was single atomic dispersed in carbon skeleton with the form of CoN4 coordination. The kinetic constant of acetaminophen (APAP) degradation with 0.1% SA-Co CNP/PMS was 6.99 times and 1.24 times as great as that of conventional CoOx-CNP/PMS and Co2+/PMS process, respectively. APAP could be efficiently degraded in a wide pH range of 3 to 9. The presence of Cl− could enhance the removal of APAP, while HCO3–, HPO4− and humic acid inhibit APAP degradation. The results of cyclic test demonstrated that 0.1% SA-Co CNP owns excellent catalytic ability and stability for PMS activation in a wide pH range of 3–9. Additionally, the reaction mechanism for APAP degradation by 0.1% SA-Co CNP/PMS was explored using ESR and trapping experiments. 1O2 was proved to be the predominant ROS. Hydroquinone was detected as the intermediate by LC-MS technique and a possible pathway for APAP removal was proposed. Finally, the degradation of APAP in real water matrix were investigated. The results showed that 0.1% SA-Co CNP/PMS not only possessed good performance for APAP degradation in tap water and surface water, but also could improve the biodegradability for secondary biochemical effluent.