Gelled Graphene Oxide–Ionic Liquid Composite Membranes with Enriched Ionic Liquid Surfaces for Improved CO₂ Separation

Abstract

Blends containing ionic liquid (IL) 1-ethyl-3-methyimidazolium tetrafluoroborate [emim][BF] gelled with Pebax 1657 block copolymers were modified by adding graphene oxide (GO) and fabricated in the form of thin film composite hollow fiber membranes. Their carbon dioxide (CO) separation performance was evaluated using CO and N gas permeation and low-pressure adsorption measurements, and the morphology of films was characterized using scanning electron microscopy, atomic force microscopy, and transmission electron microscopy. Upon small addition of GO into the IL-dominated environment, the interaction between IL and GO facilitated the migration of IL to the surface while suppressing the interaction between IL and Pebax, which was confirmed using Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy. Amplified migration of IL to the surface and better dispersion of GO stacks were further achieved under alkaline conditions. With the enriched IL on the surface, the gas permeation through the films at 0.5 wt % GO and approximately 80 wt % IL loading reached 1000 GPU for CO with their CO/N selectivity (up to 44) approaching that of pure IL.

Combining Silk Sericin and Surface Micropatterns in Bacterial Cellulose Dressings to Control Fibrosis and Enhance Wound Healing

“…Chen's team also employed (emim) (BF 4 ) for fabricating membranes on PEBAX 1657 block copolymers under similar conditions. 96 The respective CO 2 permeance (1000 GPU) reached very high but the CO 2 /N 2 selectivity became poor. Ying et al 97 recently utilized AAO substrates and (bmim)(BF 4 ) for engineering GO membrane (GO-SILM) via vacuum filtration (Fig.…”

Effect of Humidity on CO2/N2 and CO2/CH4 Separation Using Novel Robust Mixed Matrix Composite Hollow Fiber Membranes: Experimental and Model Evaluation

“…The membrane modules can be seen in the photographs in Figure 2, where Figure 2a is the commercial module and Figure 2b the module where the lab-made CHF and MMCHF membranes were placed for testing. The experiments were performed at room temperature (293K) and 4.5 bar absolute feed pressure, commonly encountered conditions in the characterization of MMMs and thin-film composite (TFC) membranes for CO 2 separation reported in literature [20,[33][34][35]. The sequence of experiments conducted in the separation plant is presented in Table 1.…”

“…If the membrane is hydrophobic, water has been reported to reduce the solubility of gases through competitive effects, lower the free volume of the polymer or reduce diffusivity by blocking effects of the pores of hydrophilic pores in MMMs [19]. If the membrane were hydrophilic, the interaction with water can be strong and increasing when exposed to humid conditions, the gas permeance being due to the increased gas diffusivity [20]. This can be prevented by coating a layer of a different character on top of the composite membrane, the support, or by combining hydrophilic and hydrophobic components in the selective layer [21].…”

Ionic Liquids‐Based Membranes for Carbon Dioxide Separation

“…Ionic liquid based composite membranes may also present in the form of mixed matrix membranes (MMMs) . They have attracted much attention because MMMs combine the preeminent film forming ability of polymer and high selectivity of filler together.…”

“…Ionic liquid based composite membranes may also present in the form of mixed matrix membranes (MMMs). [41,42,43] They have attracted much attention because MMMs combine the preeminent film forming ability of polymer and high selectivity of filler together. However, poor filler-polymer compatibility, mechanical properties and filler dispersion may adversely affect the mechanical and separation performance of the final films.…”