Efficient adsorption of bisphenol A by metal-organic frameworks-derived N-doped carbon nanoflakes: Adsorption performance and mechanism investigation

Abstract

Carbon-based materials have attracted great attentions as one of the most efficient adsorbents for wastewater treatment owing to their outstanding merits of low cost and excellent stability. In this work, we synthesized a novel N-doped carbon nanoflakes (NCF600) with high BET surface area (1609.1 m2/g) via carbonization and etching using UiO-66 as a precursor. Batch experiments demonstrated that NCF600 exhibited a high adsorption capacity for high concentrations of bisphenol A (BPA) in aqueous solutions (200 mg/g for 40 mg/L BPA) within 15 min. Furthermore, NCF600 shown good stability and reusability (the declining efficiency 3.4% after five cycles), following the pseudo-second-order model and the Freundlich adsorption model. Combined with multiple characterizations and density functional theory (DFT) calculations, we observed that pyridinic N is the main adsorption site instead of pyrrolic N and graphitic N. Considering the presence of functional groups in BPA and their interaction with NCF600, along with the influence of solution pH on the adsorption capacity of BPA, it is anticipated that the primary adsorption mechanisms will involve hydrogen bonding and π-π interactions. The present work demonstrates that NCF600 presents broad practical application prospects and provides insights for the design of N-doped carbon-based adsorbents for the effective removal of pollutants.