Study on C3H8/C3H6 Reverse Adsorption and Separation Performance of Metal-organic Framework MIL-126(Fe)

Purposes Propylene is an important olefin raw material, and the removal of propane impurities in it is very important in actual production. Metal-organic frameworks (MOFs) have great prospects for the separation and purification of propane/propylene. Among them, propane-selective adsorbents can be used to obtain high-purity propylene products in one step, which has extremely high industrial value. MIL-126(Fe) has great potential for preferential adsorption of alkanes becaused of the abundant low-polarity benzene rings that provide dense electronegativity binding sites. Methods MIL-126(Fe) was synthesized through solvothermal method. Findings The stability, C3H8/C3H6 adsorption, and separation properties of MIL-126(Fe) were studied. The results showed that MIL-126(Fe) had excellent stability. The adsorption capacity of C3H8 at 298 K and 1 bar was 185.37 cm3/g, which was higher than that of most propane-selective adsorption MOFs. The IAST selectivity for C3H8/C3H6 mixture was 1.44 at 0.1 bar and 1.23 at 1 bar. It is showed that MIL-126(Fe) had reverse adsorption on propane-propylene mixture, and its propylene recovery potential was 19.71 cm3/g, which was close to the highest level of domestic and international researches. Conclusions The results of gas breakthrough experiments showed that MIL-126(Fe) has great potential for industrial application in one-step production of high-purity propylene.