Adsorption and Diffusion of Ethyl Acetate on the Chromium-Based Metal-Organic Framework MIL-101

The adsorption equilibrium and diffusion of ethyl acetate (EA) on chromium-terphthalate-based crystals (MIL-101) are experimentally studied. The MIL-101 synthesized in this work shows an extra-high surface area of 5014 m(2).g(-1) (Langmuir). Adsorption isotherms and kinetic curves of EA on the MIL-101 are measured by a gravimetric method. Results show that the isotherms of EA can be fitted favorably by the Langmuir equation. The adsorption capacity of the MIL-101 for EA is up to 10.5 mmol.g(-1) at 288 K and 54 mbar. Diffusion coefficients of EA within the MIL-101 are in the range of (1.617 to 2.264).10(-10) cm(2).s(-1) in (288 to 318) K with a lower activation energy of 8.361 kJ.mol(-1). The isosteric heat of EA adsorption on the MIL-101 is within the range of (36.48 to 42.25) kJ.mol(-1). The isosteric adsorption heat increased slightly with the amount adsorbed of EA, implying the existence of favorable lateral interactions between EA molecules. Multiple adsorption-desorption cycles are conducted at 298 K to examine the reversibility of EA adsorption on the MIL-101. Adsorptions were performed separately at (2, 3, 5, 7, and 10) mbar, and desorptions are performed at 0.05 mbar. Experimental results show that the EA adsorption on the MIL-101 is highly reversible and the desorption efficiency of EA is up to 98.4 %.