Ultrafast antibiotic abatement: A green sulfite process boosted by engineered CoNb3S6 nanocatalysts

The development of novel advanced oxidation systems aimed at removing low-concentration antibiotic pollutants from the environment is a crucial area of focus in water pollution control. This study explores a CoNb 3 S 6 -catalyzed sulfite system for efficient and rapid metronidazole (MNZ) residues degradation in environmental water samples. A tube furnace calcination process for synthesizing CoNb 3 S 6 was developed. Scanning electron microscope results revealed that the CoNb 3 S 6 material exhibited an irregular sheet-like morphology with a thickness ranging from 80 to 200 nm. Brunauer–Emmett–Teller analyses indicated a specific surface area of 59.10 m 2 /g for CoNb 3 S 6 . Targeting MNZ as the pollutant of interest, the influence of critical parameters including solution pH, inorganic anions, CoNb 3 S 6 dosage, sodium sulfite, and MNZ concentrations on the catalytic behavior of the CoNb 3 S 6 /sulfite system was systematically investigated. Experimental results demonstrated that the CoNb 3 S 6 /sulfite system achieved 91.2 % removal of MNZ within 40 s, with the catalytic reaction following a pseudo-second-order (PSO) kinetic model. During MNZ removal process, SO 3 •− , 1 O 2 , and h + were established as the primary active species. Density functional theory (DFT) methodology was applied to analyze the molecular structure of MNZ, leading to the proposal of two possible transformation pathways. The remarkable catalytic efficacy observed in the CoNb 3 S 6 /sulfite system may be fundamentally ascribed to the synergistic interplay of Co, Nb, and S. The established CoNb 3 S 6 /sulfite system demonstrates rapid and efficient removal capabilities, making it suitable for effectively treating low-concentration MNZ pollutants in real-world environmental water samples.