Selective Adsorption of Light Alkanes on a Highly Robust Indium Based Metal–Organic Framework

Highly robust indium based InOF-1 was synthesized by the solvothermal method for the separation of C3H8/CH4 and C2H6/CH4. Its adsorption and separation performance was investigated by isotherms (CH4, C2H6, and C3H8) and breakthrough experiments. Results showed that C3H8, C2H6, and CH4 adsorption capacities of InOF-1 were 4.25, 4.14, and 0.64 mmol/g at 298 K and 100 kPa. The adsorption selectivities of C3H8/CH4 and C2H6/CH4 equimolar mixtures were up to 91 and 17 based on ideal adsorbed solution theory (IAST). Importantly, the potential of industrial separation was also confirmed by breakthrough experiments. Furthermore, we employed the configurational-biased grand canonical Monte Carlo (CB-GCMC) method to simulate their adsorption behaviors in InOF-1. It was found that the relatively higher percentages of adsorbate–adsorbate interactions in total energy and the electrostatic interactions of C2H6 and C3H8 made more efficient use of the large free space in the center pores of InOF-1 than that of CH4. Additionally, InOF-1 exhibited excellent chemical stability with retaining its framework in both acidic and alkaline solutions ranging from pH 3 to 11 for 12 h. Therefore, the research for robust InOF-1 is of great importance for industrial light alkane separation.