A Ni-based metal-organic framework with super-high C3H8 uptake for adsorptive separation of light alkanes

Abstract

The separation of C2H6 and C3H8 from CH4 is extremely important in the petrochemical industry, but the separation technology is dominated by an energy-intensive and cost-intensive process of cryogenic distillation. With lower energy consumption and cost investment, adsorptive separation technology shows great potential for the purification of natural gas. Here, we prepared a Ni-based metal-organic framework CTGU-15 and investigated its performance for the separation of light alkanes. Results show that CTGU-15 has super-high C3H8 uptake (12.13 mmol/g) and relatively low CH4 uptake (0.40 mmol/g) at 298 K and 100 kPa. The reason why CTGU-15 shows super-high C3H8 uptake was studied by comparing the pore textural properties of CTGU-15 and other benchmark adsorbents. Additionally, computational simulations were used to explore the nature of the interaction of the C3H8 gas within CTGU-15. The adsorption selectivities of C3H8/CH4 and C2H6/CH4 on CTGU-15 are 170.7 and 5.2, respectively. Breakthrough experiments show that CTGU-15 can achieve the adsorptive separation of CH4/C2H6/C3H8 mixtures. Importantly, CTGU-15 can maintain the stability of the framework after the heat treatment at <770 K, five adsorption-desorption cycles and exposure to 58% RH for 3 days. This work indicates that CTGU-15 is a promising adsorbent for CH4/C2H6/C3H8 separation.