(449au) Reverse-Selectivity of the Supported Ionic Liquid Membranes

This experimental study explores the reverse-selective potential of RTIL based membranes by lowering the solubility of the non-condensing gases like N₂ and CH₄. Particular attention was given to the reverse-selective behavior in the propane/methane and propane/nitrogen separations. For this purpose, a series of experiments were conducted in a batch gas permeance system. The permeance of the above-mentioned gases was obtained using polyvinylidene fluoride (PVDF) as the support and [emim][Tf₂N], [emim][BF₄], [emim][TfO], [emim][DCA], [emim][SCN], and [bmim][NO₃] as immobilized room temperature ionic liquid (RTIL). Furthermore, the permeance of CH₄ and N₂ were investigated in terms of hydrogen bond accepting ability of the RTIL, as an indication of the gas/ionic liquid solution nonideality. The results showed that an increase in the nonideality of the solution leads to a decrease in the permeance of CH₄ and N₂. By changing the hydrogen bond ability of the RTILs, we were able to increase reverse selectivity of the propane/methane pair from 2 to 7 and the propane/nitrogen pair from 3 to 14.