The p and d hybridization interaction in Fe-N-C boosts peroxymonosulfate non-radical activation

Abstract

Advanced oxidation processes based on non-radicals are used to remove pollutants and have attracted attention due to their adaptability to complex water environments. In this work, we dope Fe to g-C3N4 (CN) to form an Fe-N-C electronic bond bridge. Characterization and density functional theory (DFT) calculations prove that the p and d orbital hybridization of FeCN improves metalloid properties and improves electronic activity. Due to the difference of electronegativity, the local polarization electric field of C-N-Fe on the electronic bond bridge is formed. An electronic circuit of PMS/catalyst/water or pollutants is formed, which promotes the electron transfer in the process of non-radical reactions. The reaction kinetic results showed that the degradation rate constant of bisphenol A (BPA) increased by 54 times. The normalization treatment and poisoning experiment proved the catalytic active sites of Fe. Similarly, the FeCN/PMS system can satisfactorily remove BPA in a wide pH range (3–9), in the presence of inorganic anions and natural water matrix. This work provides a method for improving the process of non-radical electron transfer and provides strong technical support for stimulating the practical application of persulfate.