Fabrication of polymer/fluoride-containing salts blend composite membranes for CO2 separation

Poly (N, N-dimethylaminoethyl methacrylate)-poly (ethylene glycol methyl ether methacrylate) (PDMAEMA-PEGMEMA) and cesium fluoride (CsF) were blended and used as the separation material of composite membranes. Hollow fiber composite membranes were fabricated by coating the blend on polysulfone (PSf) hollow fiber substrate. Introduction of fluorine ion improved the separation performance of the membrane. The concentration of coating solution was adjusted to obtain a membrane with high permeance. The composite membrane showed good performance with the CO2 permeance of 30.4 GPU (1 GPU = 10^-6 cm³(STP)/(cm²·s·cmHg)), and selectivities to CO2/N2, CO2/CH4, CO2/H2 and O2/N2 of 47.2, 37.6, 1.75 and 4.70, respectively. Potassium fluoride (KF), due to its low cost, was also used as a substitute of CsF to prepare composite membrane and the permeation data showed that CsF can be replaced by KF. The effect of operating temperature on the permeation properties of the composite membrane was also investigated.