Graphene-inspired porous polymer network for ethane/ethylene separation and methane purification

Area of Science:

• Materials Science
• Chemical Engineering
• Separation Science

Background:

• Ethylene (C2H4) and methane (CH4) are vital industrial chemicals.
• Contamination by other natural gases hinders their efficient utilization.
• Existing sorbent materials show limited performance in gas separation.

Purpose of the Study:

• To introduce PPN-20, a graphene-inspired porous polymer network (PPN).
• To evaluate PPN-20's capability for separating C2H6/C2H4 and purifying CH4 from C3H8/C2H6/CH4 mixtures.
• To investigate the mechanism behind PPN-20's high adsorption performance.

Main Methods:

• Synthesis of PPN-20 with ultra-microporosity.
• Gas adsorption and selectivity measurements at 298 K and 1 bar.
• Ideal Adsorbed Solution Theory (IAST) calculations for selectivity.
• Breakthrough experiments and robustness tests.

Main Results:

• PPN-20 demonstrates high uptake capacities: 3.93 mmol/g for C2H6 and 5.98 mmol/g for C3H8.
• Achieves record-breaking IAST selectivities: 2.2 for C2H6/C2H4, 368.2 for C2H6/CH4, 40.14 for C3H8/C2H6, and 294,336 for C3H8/CH4.
• Preferential C-H···π interactions and precisely engineered pore sizes contribute to performance.

Conclusions:

• PPN-20 offers superior performance for short-chain hydrocarbon separation and purification.
• The material's ultra-microporosity and pore size engineering are key to its effectiveness.
• This study provides a pathway for designing advanced PPNs for industrial gas purification.