Capturing CO₂ by a Fixed-Site-Carrier Polyvinylamine-/Matrimid-Facilitated Transport Membrane

Here, facilitated transport membranes are fabricated based on polyimide (PI, Matrimid) and polyvinyl amine (PVAm) as gas separation membranes. Matrimid is used as the continuous phase, and the dispersed phase is PVAm, which is synthesized via Hofmann’s reaction from polyacrylamide. Also, silica nanoparticles are synthesized to study the gas separation performance. The Matrimid/PVAm and Matrimid/PVAm/silica hybrid membranes are prepared. Then, the structure of composite/blend membranes is studied by employing various characterization techniques, including scanning electron microscopy, Fourier transforms infrared spectroscopy, X-ray diffraction, and tensile stress–strain analysis. The effects of PVAm and silica concentration on CO2, CH4, O2, and N2 permeance and CO2/CH4 and CO2/N2 permselectivity at 1 bar and 30 °C are reported. In dry conditions, the CO2 permeance increased and permselectivity of CO2/CH4 and CO2/N2 significantly enhanced from 21.0 to 267.3 and 15.8 to 133.6, respectively. Improvement in gas separation by adding PVAm particles may return to active carriers’ concentration as amine groups react with CO2, which is favorable for CO2 (CO2–carrier complex and uncompleted CO2)-facilitated transport. Also, the number of ions formed by the reaction increases swiftly.