Ether-functionalized ionic liquid based composite membranes for carbon dioxide separation

Abstract

The efficient separation of CO 2 from other light gases has received growing attentions due to its importance in reducing greenhouse gas emissions and applications in gas purification. In this work, we developed a series of composite membranes composed of ether-functionalized pyridinium-based ionic liquids ([E n Py][NTf 2 ]) and cellulose acetate (CA) polymer matrices to improve CO 2 separation performance. CA + [E n Py][NTf 2 ] and CA + [C n Py][NTf 2 ] composite membranes were fabricated by a casting method. The CO 2 , N 2 and CH 4 permeabilities of the CA + IL composite membranes were measured, and the CO 2 /N 2 and CO 2 /CH 4 permselectivities were further calculated. The results showed that the CA + 40 wt% [E 1 Py] [NTf 2 ] composite membrane exhibits approximately a seven-fold increase in CO 2 permeability with CO 2 / N 2 and CO 2 /CH 4 permselectivities of 32 and 24, respectively. The characterization results showed that the mechanical properties and thermal stabilities of the CA + [E 1 Py][NTf 2 ] composite membranes are affected by both plasticizing effect and affinity of the ILs for the gases, which also lead to the changes in the CO 2 /N 2 and CO 2 /CH 4 permselectivities. Compared with membranes containing the nonfunctionalized analogues [C n Py][NTf 2 ], the addition of [E n Py][NTf 2 ] improves the ideal permselectivities of CA + IL composite membranes, whereas it decreases slightly the gas permeabilities. Scheme 1 The chemical structures of (a) [E n Py][NTf 2 ], (b) [C n Py][NTf 2 ] and (c) cellulose acetate. This journal is

The Impact of Reactive Ionic Liquids Addition on the Physicochemical and Sorption Properties of Poly(Vinyl Alcohol)-Based Films

“…The RILs content growth from 9 to 23 wt % smoothens the PVA-RILs membrane surface ( Figure S2 ) what was demonstrated by diminishing R a values ( Table 3 ). Such tendency was also indicated by Deng et al [ 54 ] in the research on the cellulose acetate (CA)-based films modified with ether-functionalized pyridinium ILs ([E n Py][NTf 2 ]). The researchers pointed out the CA films surface smoothening for an IL amount higher than 20 wt % as a result of liquid nature of tested [E n Py][NTf 2 ] ionic liquid [ 54 ].…”

Nafion/IL hybrid membranes with tuned nanostructure for enhanced CO2 separation: effects of ionic liquid and water vapor

“…6 For instance, neutral polymers such as a poly(ether-b-amide) block copolymer (Pebax ® ), poly(vinylidene fluoride-co-hexafluoropropylene) P(VDF-HFP), poly(vinylidene fluoride) (PVDF), and polyimides (PIs) have been successfully used to prepare polymer/IL membranes. [7][8][9][10][11] By judiciously choosing the polymer matrix and IL additive, significant improvements in both gas permeability and selectivity can be achieved. 10,12 A non-negligible drawback, however, is that the low-molecularweight constituents of ILs gradually leach out of the membrane over time, thereby promoting a corresponding loss of separation performance.…”

Pebax-based composite membranes with high gas transport properties enhanced by ionic liquids for CO2 separation

“…Compared to the traditional methods, such as solvent absorption, pressure-and temperature-swing adsorption, and cryogenic distillation, the membrane method has become an emerging technology because of its advantages of environmentally friendliness, lower energy consumption, and ability for scale up. 3,4 Owing to the good mechanical stability and easy processability, polymeric membranes have attracted considerable attention and have been studied in the separation of biogas (CO 2 /CH 4 ), 5,6 ue gas (CO 2 /N 2 ), 7,8 syngas (CO 2 /H 2 ), 9,10 and other light gases. 11 However, there is a trade-off between permeability and selectivity known as the "Robeson upper-bound" that limits the application of polymeric membranes for gas separation.…”