Flexible and mechanically-stable MIL-101(Cr)@PFs for efficient benzene vapor and CO2 adsorption

Abstract

Novel composite MIL-101(Cr)@PFs were successfully prepared by immobilizing MIL-101(Cr) crystals onto the 100% virgin pulp fibers (PFs), and then characterized by N₂ adsorption, X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR) and thermal analysis. The adsorption isotherms of CO₂ and benzene vapor on MIL-101(Cr)@PFs were measured by a volumetric method. Mechanical stability of sheet MIL-101(Cr)@PFs were tested on an oscillator with adjustable oscillation frequency of 2 and 4 Hz. Results showed that the as-synthesized MIL-101(Cr)@PFs demonstrated similar gas uptake to the parent MIL-101(Cr) as well as excellent stability. The surface area of MIL-101(Cr)@PFs increased with the loaded amount of MIL-101(Cr). The uptakes of 67MIL-101(Cr)@PF for CO₂ and benzene vapor reached 2.13 mmol g⁻¹ and 10.29 mmol g⁻¹ at 298 K, respectively, close to those of unit mass of MIL-101(Cr) loaded on the pulp fibers, suggesting high utilization efficiency of MIL-101(Cr) after casting on PFs. MIL-101(Cr)@PFs prepared in this work were flexible. 50MIL-101(Cr)@PFs can be distorted up to 360° without damage. Importantly, mass retention rate of MIL-101(Cr)@PFs maintained up to 99% after vibration of 120 minutes at 2 Hz or 4 Hz, implying that MIL-101(Cr) crystals had been anchored on pulp fibers stably. It could be expected that the sheet MIL-101(Cr)@PFs would become a promising adsorption material for gas adsorption and purification in practical applications.