One-step propylene purification from a quaternary mixture by a single physisorbent

Area of Science:

• Materials Science
• Chemical Engineering
• Adsorption Science

Background:

• Adsorptive separation is crucial for high-purity product generation.
• Current porous materials struggle to capture multiple impurities simultaneously.
• Efficient propylene (C3H6) purification from C3 mixtures remains a significant challenge.

Purpose of the Study:

• To design novel metal-organic frameworks (MOFs) for selective multi-impurity capture.
• To demonstrate a MOF capable of one-step purification of C3H6 from a quaternary mixture.
• To develop an energy-efficient alternative for C3H6 production.

Main Methods:

• Design and synthesis of a series of MOFs (ZU-921 to ZU-924) featuring cooperative binding sites.
• Utilizing ligand engineering to fine-tune the density of electronegative sites for selective adsorption.
• Conducting breakthrough experiments using a scaled-up column to evaluate C3H6 purification performance.

Main Results:

• ZU-921 demonstrated selective adsorption of alkynes, allenes, and alkanes over alkenes.
• Ultra-high purity C3H6 (99.99%) was achieved in a single step from a C3 quaternary mixture.
• High productivity (17.27 L/kg) was obtained in a 10-times scaled-up column.

Conclusions:

• The designed MOFs offer a viable strategy for advanced adsorbent design for multi-impurity capture.
• ZU-921 provides an effective and energy-efficient solution for C3H6 purification.
• This work advances the field of selective adsorptive separation for industrial applications.