Coupled adsorption and non-radical dominated mechanisms in Co, N-doped graphite via peroxymonosulfate activation for efficiently degradation of carbamazepine

A ZIF-derived Co, N-doped graphitic carbon prepared by calcination exhibited excellent carbamazepine (CBZ) removal ability over a broad pH range for peroxymonosulfate (PMS) activation. The impact of calcining tem-perature on catalyst constitution and catalytic behavior were studied through characterization and performance experiments. Benefiting from the synergy of adsorption and catalysis, CZIF-1000/PMS (with a 1000 degrees C pyrolysis temperature) system demonstrated outstanding catalytic capability, with 96.8 % removal efficiency supported by optimum parameters (catalyst dosage, 50 mg/L, PMS dosage, 0.4 mM, CBZ concentration, 5 ppm, and initial pH, 5.8). The graphitic N, pyrrolic N, C--O group, Co3+ and Co0 were revealed to be the activation centers by X-ray photoelectron spectroscopy (XPS). Mechanisms exploration suggested that dual active pathways, including singlet oxygen-dominated non-radical pathway and sulfate radical-dominated radical pathway were involved in the reaction mechanism. Besides, a total of ten intermediates were detected and CBZ degradation pathways were derived subsequently.