Adsorption behavior of carbamazepine on Zn-MOFs derived nanoporous carbons: Defect enhancement, role of N doping and adsorption mechanism

Metal-organic frameworks (MOFs)-derived nanoporous carbons have attracted widespread concern as adsorbents to remove endocrine-disrupting chemicals (EDCs) in water. However, to explore MOFs-derived nanoporous carbons with high absorption performance is still one of the great challenges, and an in-depth analysis of the adsorption mechanism is insufficient. Herein, two nanoporous carbons were prepared through the pyrolysis of different Zn-MOFs, and their absorptivity was assessed using carbamazepine (CBZ) as the target pollutant. Owing to the higher specific area and the hierarchical pore structure, MOF-5-derived nanoporous carbon (MC) delivered a much higher adsorption capacity (663.7 mg/g) and faster uptake rate (634.5 mg/(g·min)) than ZIF-8-derived nanoporous carbon (ZC) and commercial powdered activated carbon (AC). Furthermore, the studies of the structure-absorptivity relationship revealed that the graphitic defect demonstrates an enhanced efficacy in the absorption performance of nanoporous carbons whereas the effect of the doped N is negligible. The hydrophobic interaction is the dominant contribution to the CBZ adsorption on MC rather than the π-π interaction, electrostatic attraction, and hydrogen bond. Profited from the unique adsorption mechanism, MC shows an excellent anti-interference capability and good reuse stability. This work provides new insight into the design of high-efficiency adsorbents derived from MOFs toward the removal of EDCs from water.