Poly(ionic liquid)–ionic liquid membranes with fluorosulfonyl derived anions: characterization and biohydrogen separation

Unformatted postprintClean and sustainable energy production has become a key global issue concerning the world’s energy shortage and environmental problematic. Despite the recognized potential of biohydrogen (bioH2) for sustainable development, there are still issues regarding its production and purification, such as the elimination of CO2, N2, and other impurities (H2O and H2S), so that an enriched H2 stream can be obtained for efficient energy generation. The use of poly(ionic liquid)s (PILs) and their derived composite materials incorporating ionic liquids (PIL–IL) has been considered as a highly promising strategy to design membranes with improved CO2 separation. In this study, membranes of pyrrolidinium-based PILs containing symmetric or asymmetric fluorosulfonyl derived anions, namely bis(fluorosulfonyl)amide ([FSI]–), (trifluoromethyl)sulfonyl-N-cyanoamide ([TFSAM]–) and (trifluoromethyl)sulfonyl-N-trifluoroacetamide ([TSAC]–), were prepared by the incorporation of different amounts of structurally similar ILs. The PIL–IL membranes were characterized by different techniques (TGA, DSC, FT-IR and Raman) and their CO2/H2 and H2/N2 separation performances were investigated. Higher CO2/H2 selectivities were obtained for PIL FSI–40 [C2mim][FSI] (αCO2/H2 = 9.0) and PIL TFSAM–40 [C2mim][TFSAM] (αCO2/H2 = 7.1) compared to those of PIL–IL membranes containing the conventional [TFSI]– anion at similar or even higher amounts of IL’s incorporation.Andreia S. L. Gouveia is grateful to FCT (Fundação para a Ciência e a Tecnologia) for her Doctoral (SFRH/BD/116600/2016) research grant. Liliana C. Tomé has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement No 745734. This work was supported by FCT through the project PTDC/CTM-POL/2676/2014. Centro de Química Estrutural acknowledges the financial support of Fundação para a Ciência e Tecnologia (UIDB/00100/2020). Elemental analysis and Raman spectroscopy were performed with the financial support from Ministry of Science and Higher Education of the Russian Federation using the equipment of Center for molecular composition studies of INEOS RAS

Ionic liquid-based semi-interpenetrating polymer network (sIPN) membranes for CO2 separation

This work explores the preparation of ionic liquid (IL)-based semi-interpenetrating polymer network (sIPN) membranes composed of poly(ethylene oxide) (PEO) network and linear nitrile butadiene rubber (NBR), incorporating up to 66 wt% of three ILs with a common cation ([C2mim]+) and different anions ([C(CN)3]–, [NTf2]– and [FSI]–). All sIPN/IL membranes were characterized by Fourier-transform infrared (FT-IR) spectroscopy, thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and puncture tests. Ideal CO2/N2 and CO2/H2 separation performances of the prepared sIPN/IL membranes were investigated at T = 20 ◦C and 35 ◦C, respectively, and 1 bar of feed pressure. The incorporation of both [C2mim][NTf2] and [C2mim][FSI] ILs allowed to obtain sIPN/IL membranes with higher IL contents (66 wt%) compared to previously reported PIL–IL membranes with similar IL structures (40 wt %). The membranes containing [NTf2]– and [C(CN)3]– anions showed improved thermal stability compared to the neat PEO/NBR sIPN, being thermally stable up to 300 ◦C. Although sIPN/IL membrane mechanical properties were affected by the incorporation of IL, all membranes revealed high elongation properties (elongation upon puncture = 68–170%), mainly due to the presence of NBR component in the sIPN structure. The highest CO2/N2 permselectivity was obtained for the sIPN/66 wt% [C2mim][C(CN)3] membrane, while the sIPN/66 wt% [C2mim][FSI] membrane revealed the highest CO2 and N2 permeabilities. The incorporation of 66 wt% of [C2mim][FSI] into the sIPN also showed superior CO2/H2 separation performance, with a CO2 permeability of 727 Barrer and a CO2/H2 permselectivity of 10.9info:eu-repo/semantics/publishedVersio

Processing of poly(ionic liquid)-ionic liquid membranes using femtosecond (fs) laser radiation: Effect on CO2 separation performance

Femtosecond (fs) laser micromachining on polymeric materials is a single-step, and contactless manufacturing technology. Knowing the potential of poly(ionic liquid)s (PILs) and their derived composite materials incorporating ionic liquids (PIL-IL) to design membranes with improved CO2 separation, we here explore for the first time the creation of microchannels on the surface of PIL-IL materials by laser ablation using femtosecond laser radiation. PIL-IL membranes composed of pyrrolidinium-based PILs containing the [NTf2](-) and [C(CN)(3)](-) anions and different amounts of their corresponding ILs (40 and 60 wt%) were prepared and micromachined using fs laser pulses varying the pulse repetition rate, scanning speed, and pulse energy. The morphology of the fs laser modified PIL-IL samples was investigated through scanning electron microscopy (SEM), while the influence of the fs laser processing on the membranes structure was analyzed by solid-state nuclear magnetic resonance (ssNMR), Fourier-transform infrared (FT-IR) spectroscopy, and X-ray photoelectron spectroscopy (XPS). The CO2/N-2 and CO2/H-2 separation performances of the irradiated membranes were also evaluated and compared to those of the non-irradiated. Depending on the parameters used, fs laser processing was successful in modifying the surface of PIL-IL membranes through the formation of microchannels around 55-60 mu m deep. Significant improvements in CO2, N-2 and H-2 permeabilities were achieved for the irradiated PIL-IL membranes, maintaining their CO2/N-2 and CO2/H-2 permselectivities.info:eu-repo/semantics/publishedVersio