The role of iron-doped g-C3N4 heterogeneous catalysts in Fenton-like process investigated by experiment and theoretical simulation

• CNF presented positive effect to enhance the degradation of CBZ in Fenton-like reaction. • Adsorption of H 2 O 2 on the Fe-O site of CNF promoted the electron transfer between CNF and H 2 O 2 . • Structural deformation of adsorbed H 2 O 2 molecule was conducive to the generation of ·OH radicals. • Protein-like materials with a low humification degree were mainly produced in the degradation of CBZ. • Thirteen intermediates were identified according to LCMS analysis and DFT calculation. The Fenton-like process provides a promising method to produce reactive radicals for the degradation of refractory organic pollutants in environmental remediation. In this study, the iron-doped g-C 3 N 4 (CNF) coupled with H 2 O 2 was applied to enhance the degradation of carbamazepine (CBZ). And the role of CNF was elucidated by experiment and density functional theory (DFT) calculations. The largest CBZ removal efficiency of 99.02% was achieved in acid condition (pH = 3) with the addition of 0.5 g/L 14% CNF and 50 mM H 2 O 2 . Thirteen intermediates were identified based on high performance liquid chromatography coupled with mass spectrometer (LCMS) and DFT calculations. The degradation products of CBZ were mainly protein-like materials with a low humification degree. During the degradation process, H 2 O 2 was preferentially adsorbed on the active Fe-O site of CNF by hydrogen bonding, hence the promoted electron transfer from H 2 O 2 to Fe(III) contributed to the generation of Fe(II). Certain deformation of H 2 O 2 was observed that the O-O bond length increased to about 1.51 Å. As a result, large amounts of radical species (·OH) were generated by H 2 O 2 decomposition, which was responsible for attacking the CBZ molecules and proceeding the degradation reaction.