N-doped graphitic carbon as a nanoporous MOF-derived nanoarchitecture for the efficient sonocatalytic degradation process

Abstract Here, a nanoporous N-doped graphitic carbon (NC) obtained via the pyrolysis of the zeolitic imidazolate framework-67 (ZIF-67) in the N2 atmosphere and then etched with hydrofluoric acid (HF) to remove the cobalt particles. The carbonized imidazoles in the framework of the ZIF-67 converted to the formation of N-doped graphitic sheets. The N2 adsorption-desorption isotherms verified an arise in the surface area after etching the carbonized ZIF-67 and removing the Co nanoparticles (384 m2/g). Then, the prepared nanoporous carbon (NCZIF-67) was employed as a catalyst under the ultrasonic (US) irradiation for the degradation of the methylene blue (MB) as a model thiazine-based dye. The effects of main operational parameters including the initial pH, MB concentration, catalyst dosage, and ultrasonic power on the coupled US/NCZIF-67 process were investigated. The addition of radical scavengers and enhancers revealed the main role of reactive oxygen species in the treatment process particularly hydroxyl radicals (•OH), in which their presence is confirmed by the photoluminescence (PL) spectra. The GC–MS method was performed for recognition of the seven detectable intermediates during the MB degradation.