Design and Component Contribution Study of MIL-100(Fe)-Derived Materials for Adsorption Removal of Antipyrine from Water

Abstract

The use of metal–organic framework-derived materials for removing micropollutants from water is increasing, but precise composition control remains a challenge. In this study, 14 MIL-100(Fe)-derived materials were synthesized to adsorb and remove antipyrine (ANT) from water by optimizing the heating rate, pyrolysis temperature, and activation methods. The adsorbents demonstrated excellent ANT removal performance across a pH range of 3 to 11, as well as in complex water bodies. They also exhibited easy recovery and outstanding regeneration capabilities. Under the optimized conditions (i.e., ANT content: 10 mg/L, M-600–2 dosage: 0.1 g/L, and pH: 7), M-600-10 displayed the highest adsorption capacity (23.10 mg/g for ANT) while MIL-100(Fe) had limited adsorption capability (2.56 mg/g for ANT). The adsorption process was exothermic and spontaneous, influenced by both membrane diffusion and intraparticle diffusion, and followed the Freundlich and pseudo-second-order models. Despite variations in surface areas (75.70–261.91 m²/g), total pore volumes (0.2019–0.5984 cm³/g), and average pore sizes (7.47–13.99 nm), there was no strong linear relationship with adsorption capacity (7.47–15.99 mg/g). The major components, including Fe/pyrrolic N-doped graphene (PING), Fe₃C/PING, Fe₃O₄/PING, and PING, had calculated adsorption energies of −0.94, −2.16, −0.79, and −2.24 eV, respectively, which correlated positively with Bader charge transfer numbers. The adsorbents relied on van der Waals forces for ANT adsorption, with PING exhibiting the strongest interactions and Fe₃O₄/PING exhibiting the weakest. These findings enhance the theoretical understanding of derived materials and expand their application in water purification.