YU Ying, SUN Xuejiao, YAN Jian, et al. Adsorption equilibrium and mechanism of ethanol on MIL-101(Cr)[J]. CIESC Journal, 2016, (1): 300-308.
DOI:
YU Ying, SUN Xuejiao, YAN Jian, et al. Adsorption equilibrium and mechanism of ethanol on MIL-101(Cr)[J]. CIESC Journal, 2016, (1): 300-308.DOI: 10.11949/j.issn.0438-1157.20151052.
Adsorption equilibrium and mechanism of ethanol on MIL-101(Cr)
The adsorption performance and adsorption mechanism of ethanol on MIL-101(Cr) were investigated. MIL-101(Cr) was synthesized using a hydrothermal synthesis method
and characterized using N2 adsorption measurements
powder X-ray diffraction
and Fourier transform infrared spectroscopy. The adsorption isotherms of ethanol and water vapor were measured by static adsorption method at different temperatures
and ethanol adsorption mechanisms on four types of adsorptive sites in MIL-101 were discussed. The isosteric heats of ethanol and water adsorption were calculated according to these isotherms. The adsorption and desorption of ethanol on MIL-101 were evaluated. Results show that adsorption capacity of MIL-101(Cr) for ethanol is up to 20.3 mmol·g-1 at 298 K
much higher than those of some traditional adsorbents. At low pressure
the adsorption capacity of MIL-101 for ethanol is higher than that for water vapor
which could be ascribed to larger dipole moment and dynamic diameter of ethanol compared to water molecule. In addition
the isosteric heat of ethanol adsorption on MIL-101 is higher than that of water vapor adsorption. At high pressure
multilayer adsorption or cage filling occurs
so the molecule with large dynamic size will fill within MOFs with less moles than that with small dynamic size due the limitation of pore volume of MOFs. As a consequence
the adsorption capacity of MIL-101 for ethanol is lower than that for water vapor because the dynamic diameter of ethanol (0.45 nm) is larger than that of water molecule (0.268 nm). The ethanol adsorption and desorption isotherms show that ethanol adsorption on MIL-101 is highly reversible.