Halogen-modified metal-organic frameworks for efficient separation of alkane from natural gas.

As a rich green energy source, natural gas is widely used in many fields such as the chemical industry, automobile energy, and daily life. However, it is very challenging to separate and recover CH and CH from natural gas. Metal-organic frameworks (MOFs) as an emerging type of multi-pore porous materials show huge potential in gas adsorption separation. Herein, we report pillar-layered MOFs, Ni (BDC)(DABCO) (DMOF-X), modified by halogen atoms (F, Cl, Br), and investigate their CH/CH/CH separation performance. The experimental results show that DMOF-Cl exhibited a extremely high adsorption capacity for CH and CH. Under the conditions of 298 K and 100 kPa, the adsorption capacities for CH and CH on DMOF-Cl are as high as 6.23 and 4.94 mmol g, which are superior to the values for most of the porous materials that have been reported. In addition, DMOF-Cl also shows high CH/CH (5: 85, V/V) and CH/CH (10: 85, V/V) separation selectivities, with values of 130.9 and 12.5, respectively. Finally, DMOF-Cl also demonstrated great potential as an adsorbent for separating CH/CH/CH.