Leveraging Surface Chemistry and Pore Shape Engineering in a Metal-Organic Framework for One-Step Olefin Purification

Purifying olefin from ternary paraffin/olefin/alkyne mixtures through a one-step adsorption process is extremely desirable. Herein, a stable zirconium(IV) metal-organic framework with a customized pore surface composed of nonpolar phenyl and slightly polar thiophene rings is reported to access the adsorption preference of paraffin and alkyne over olefin. Noteworthily, this material displays a superior ability to discriminate C-3 hydrocarbon molecules, which is principally more challenging compared with C-2 ones and rarely documented. Computational studies disclose that its featured pore shape fits well with C-3 gas molecules, enabling them to get close contact with the immobilized affinity sites. Leveraging surface chemistry and pore shape engineering synergistically gives rise to excellent C-3 adsorption capacities (>5 mmol g(-1)) and concurrently high C3H8/C3H6 (1.4) and C3H4/C3H6 (1.9) selectivities (at 298 K and 1 atm). Dynamic column breakthrough experiments demonstrate that one-step purification of C2H4 and C3H6 can be simultaneously realized on this material.

Automated summary

A stable metal-organic framework with a customized pore surface is reported to selectively adsorb paraffin and alkyne over olefin. This material exhibits excellent discrimination ability for C-3 hydrocarbon molecules and high selectivity for C3H8/C3H6 and C3H4/C3H6. Experimental results confirm its potential for simultaneous purification of ethylene and propylene.