USE OF NONPOROUS POLYMERIC FLAT-SHEET GAS-SEPARATION MEMBRANES IN A MEMBRANE-LIQUID CONTACTOR - EXPERIMENTAL STUDIES

Flat-sheet non-porous asymmetric poly(vinyltrimethylsilane) (PVTMS) me mbranes and composite membranes comprising a dense layer of polydimeth ylsiloxane/polyphenylsilsesquioxane (PDMS/PPSQ) block copolymer were e valuated for low-temperature bubble-free deoxygenation of water flowin g in a two-channel countercurrent liquid-membrane contactor. A novel l arge-scale three-channel flowing-liquid-membrane module (selective mem brane valve), designed for gas separation, is also described. The syst em comprised PVTMS or PDMS/PPSQ non-porous membranes which acted as ga s-permeable barriers. A membrane system (SMV) in which pure water form ed a flowing liquid membrane was evaluated to control hydrogen transfe r rates. The liquid flowing along the turbulence-promoter spacers betw een the membranes reduced liquid-film resistance. The overall mass-tra nsfer coefficients were found to be a function of the liquid flow rate . The liquid-film resistance controlled the rate of gas transfer in su ch membrane contactors.