Construction of synergistic binding sites in a robust MOF for excellent C2H4 purification and C3H6 recovery performance

Abstract

C2H4 purification and C3H6 recovery by physisorbents face a huge dilemma to combine good separation performance, easy scalability with economic feasibility, and great stability for industrial applications. Here, we proposed a strategy of building multiple affinities in a robust Ni(bdc)(dabco)0.5 for highly effective one-step C2H4 purification from C3H6/C2H4 mixture in MTO and steam cracking of naphtha products. Due to nonpolar pores edited by available O binding sites with suitable pore restriction and high BET surface area, Ni(bdc)(dabco)0.5 shows not only one of the highest C3H6 uptake (80.6 cm3(STP) g-1) at 0.1 bar and excellent C3H6 uptake (148.8 cm3(STP) g-1) at 1.0 bar but also top-level C3H6/C2H4 selectivity (10.7) and separation potential (115.3 cm3(STP) g-1) at 298 K and 1.0 bar. Meanwhile, the C3H6/C2H4 uptake ratio (10.9) exhibits a record value at 0.1 bar with a lower (26.7 kJ mol-1), breaking the trade-off of C3H6/C2H4 separation and setting a new benchmark. Theoretical simulation and in situ FT-IR unveiled that the nonpolar pore with rich O binding sites supplies stronger multiple supramolecular affinities with C3H6 over C2H4. Breakthrough tests prove its utter separation performance of the C3H6/C2H4 with good recyclability, offering one of the highest dynamic C3H6 uptake and C2H4 productivity (101.2 and 57.3 cm3(STP) g-1). The MOF is easy to synthesize on a gram-scale from cheap reagents. Ni(bdc)(dabco)0.5 fulfills a benchmark combination of good separation performance, great stability, good renewability, and easy scalability, which awards it a great prospect for industrial C2H4 purification.