Carbon Capture Using Amine-Functionalized Metal-Organic Framework Membranes

摘要

Post-combustion carbon capture from flue gas requires selective CO₂ separation under humid conditions at low partial pressures. We report amine-functionalized MOF membranes (UiO-66-NH₂-PEI) fabricated by interfacial polymerization on porous α-alumina supports, achieving CO₂/N₂ selectivity of 68.5 and CO₂ permeance of 1,420 GPU at 55°C with 15 vol% CO₂ feed mimicking coal-fired power plant flue gas. The polyethyleneimine (PEI) grafting density was optimized at 2.8 mmol/g, balancing chemisorption capacity with diffusion kinetics. Long-term permeation tests over 500 hours show <5% decline in selectivity under 85% relative humidity, attributed to the hydrophobic Zr₆O₄(OH)₄ backbone shielding amine sites from water competition. Techno-economic analysis indicates capture costs of $42/tonne CO₂ at 90% capture rate for a 500 MW plant.