Interfacially polymerized polyetheramine thin film composite membranes with PDMS inter-layer for CO₂ separation

Polyether based thin film composite (TFC) membranes were developed by interfacial polymerization (IP) on polysuylfone (PSf) ultra-filtration membrane with poly (dimethylsiloxane) (PDMS) inter-layer. Polyetheramine (PEA) and Trimesoyl Chloride (TMC) were selected as aqueous monomer and organic monomer, respectively. The thickness of the PDMS inter-layer was 550nm, while IP separation layer was only 100nm. The effects of the PDMS inter-layer and the PEA molecular weight on the TFC membrane performance were investigated. The gas permeation results show that the TFC membrane with PDMS inter-layer exhibits higher CO₂/N₂ selectivity compared to the membranes without PDMS inter-layer. PDMS inter-layer is able to eliminate the defects on the support membrane and diminish the TMC hydrolysis as well. Among the membranes prepared with three different molecular weight PEAs (ED-600, ED-900 and ED-2003), the membrane of ED-900 exhibits the best performance with an impressive CO₂ permeance of 360 GPU and CO₂/N₂ selectivity of 67.2 for a mixture CO₂/N₂ (20/80 by volume), while for a mixture of CO₂/CH₄ (10/90 by volume) it demonstrates CO₂ permeance of 275 GPU and CO₂/CH₄ selectivity of 31.6.