Efficient activation of peracetic acid by Fe-doped g-C3N4 for selective degradation of emerging contaminants: Unraveling the role of reactive complex.

Peracetic acid (PAA)-driven advanced oxidation processes (AOPs) are increasing favored for water treatment due to their environmentally benignity and ease of activation. However, the development of low-cost and high-performance activators is still a primary challenge. In this study, Fe-doped g-C3N4 (Fe-N-C) was fabricated as an efficient peracetic acid (PAA) activator for sustainable degradation of emerging contaminants (ECs) like bisphenol A (BPA) with a removal efficiency of 97.8 %. Quite different from the reported non-radical involved catalytic studies, Fe-N-C-PAA complex (Fe(III)-OO(O)CCH3) was formed and served as the primary reactive species rather than high-valent iron-oxo species (FeV=O) and singlet oxygenation (1O2) for the oxidation of BPA on the basis of electron paramagnetic resonance (EPR) spectra, chemical quenching and probe tests, Raman spectroscopy, 18O isotope labeling tests, electrochemical analysis and density-functional theory (DFT) calculations in the Fe-N-C/PAA process. Satisfactory BPA removal efficiency can still be obtained with water matrices, in actual water, after 5 cycles of Fe-N-C, at the flow-through device with carbon felt for 120 h. BPA was successfully detoxified within 60 min and the probable degradation pathway of BPA was elucidated with the assistance of DFT calculations. The correlation between kobs and Hammett constants σ+ or half-wave potentials (φ1/2) of different organics implied that the contaminants with greater electron-donating capacity were more prone to be oxidized. This study advances the understanding of metal-PAA complex, offering novel insights into PAA activation using multiphase iron-based catalysts and their potential for practical environmental applications.