The efficient degradation of paracetamol using covalent triazine framework-derived Fe-N-C activated peroxymonosulfate via a non-radical pathway: Analysis of high-valent iron oxide, singlet oxygen and electron transfer

The abundant and environmentally friendly metal iron (Fe) is an excellent candidate to activate perox-ymonosulfate (PMS) for the oxidative decomposition of organic pollutants. However, Fe-based activators have disadvantages of high efficiency only in a narrow pH range and easily generated Fe-sludge. Therefore, developing wide pH range efficient and stable Fe-based PS activators is needed. In this study, iron-nitrogen-carbon (Fe-N-C) activators were prepared using covalent organic frameworks containing homogeneous micropores and high porosity as a precursor. The Fe-Nx-rich activator showed an outstanding activity and a high stability in the heterogeneously activated PMS system. It found that the 10 mg/L paracetamol (PCT) could be degraded completely within 5 min when adding 30 mg/L activator and 3 mM PMS. Furthermore, the system shows good performance in an extensive buffer pH range (2.6-10.67). The quenching experiments and intermediate product tests supported that the high-valent iron-oxo species is the major reactive oxygen species (ROS) in this system, and the designed experiments confirmed that Fe-N as the active site that in charge of activating PMS. This work provides insights for improving the activation efficiency and expanding the pH working range of iron-based catalysts in the field of advanced persulfate oxidation.

Automated summary

In this study, iron-nitrogen-carbon (Fe-N-C) activators were prepared using covalent organic frameworks as a precursor. The Fe-Nx-rich activator showed outstanding activity and high stability in the activated PMS system, and it could effectively degrade paracetamol within a short time and in a wide pH range.