Polytetrafluoroethylene (PTFE)-Sputtered Polypropylene Membranes for Carbon Dioxide Separation in Membrane Gas Absorption: Hollow Fiber Configuration

Polytetrafluoroethylene (PTFE) plasma sputtering of polypropylene (PP) membranes allows the formation of an ultrathin fluorinated hydrophobic surface that retains the microporous surface structure of the underlying membrane. The absorption results presented in this paper show that the novel PP membrane material performs well for the separation of CO2 from other gases, using an amine-based solvent. Hollow fiber membrane experiments show that the plasma-treated hollow fiber membrane has a superior CO2 mass transfer rate to untreated PP when coupled with monoethanolamine solvent flowing through the fiber lumen for at least 45 h of absorption time. The CO2 mass-transfer rate through the treated hollow fiber membrane is also comparable with that of other researchers who have absorbed CO2 into amine solvents using PTFE hollow fibers and higher than that measured using packed column technology with structured packing and amine solvents.