| This experimental study explore the reverse-selective potential of RTIL based membranes by lowering the solubility of the non-condensing gases like N2 and CH4. It explored reverse-selectivity by measuring the permeance of carbon dioxide, nitrogen, methane, propylene, propane, 1-butene, and butane in supported ionic liquid membranes (SILM). 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). The results showed that permeance of carbon dioxide was the highest in [emim][Tf2N], while it was the lowest in [bmim][NO3]. Moreover, permeance of the tested gases increased in the following order of anions: [Tf2N] > [TfO] > [BF4] > [SCN] > [DCA] > [NO 3]. In addition, the molar volume of the tested RTIL has a positive effect on the permeance of the tested gases. However, for the viscosity less than 30 cP, an increase in the viscosity of the tested RTILs leads to an increase in the permeance. In contrast, for the viscosity larger than 30 cP, the permeance decreases with an escaltion in the viscosity. Furthermore, the permeance of CH4 and N2 was 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 N 2, which is in agreement with results reported by Carvalho for CH 4 [1]. |
