Facile synthesis of N-rich carbon nanosheets derived from antibiotic mycelial dregs as efficient catalysts for peroxymonosulfate activation

Abstract

Nitrogen-rich carbon nanosheets using hazardous waste penicillin mycelial dregs (PMD) as the sole precursor were successfully synthesized amid molten salt-assisted pyrolysis and applied as catalysts for peroxymonosulfate (PMS) activation to degrade acid orange 7 (AO7). The structural properties and the associated catalytic performances of carbon nanosheets were precisely regulated by molten salt (NaCl/KCl) mass ratios and pyrolysis temperatures. Carbon nanosheets prepared at a molten salt ratio of 6 and a pyrolysis temperature of 800 °C possessed an optimized catalytic performance, achieving both high effective and efficient decolorization of AO7 than activated carbon catalysts. It was likely attributed to the combination of high graphitic N content and defective carbon structures from nanosheets through quantitative structure-activity relationships analysis. Both radical and non-radical pathways were recognized to be responsible for AO7 degradation, while surface-bound radicals generated from catalyst surface-PMS complexes in non-radical pathways were the main reactive oxygen species. This work offers a green and facile method to prepare high graphitic N content and defect-rich carbon nanosheets from nitrogen-rich biowastes, highlighting its promising catalytic properties for environmental remediation, synchronously expanding the means of resourceful and harmless treatment of PMD to improve the sustainability of antibiotic pharmaceutical production.