Facilitated transport membrane with functionalized ionic liquid carriers for CO₂/N₂, CO₂/O₂, and CO₂/air separations

Abstract

CO2 separations from cabin air and the atmospheric air are challenged by the very low partial pressures of CO2. In this study, a facilitated transport membrane (FTM) is developed to...

Transport and Energetics of Carbon Dioxide in Ionic Liquids at Aqueous Interfaces

“…Despite being investigated primarily in pure phases, ILs have also been integrated into gas-selective membranes. − Pioneering work by Richard Noble’s group demonstrated the potential of supported IL membranes, achieving CO 2 /N 2 selectivity as high as 61 and permeability/selectivity exceeding that of existing polymer membranes. , The exceptional performance of supported IL membranes can be attributed to the enhanced solubility and transport of CO 2 when confined within a membrane structure. , However, optimizing selectivity and permeability simultaneously remains challenging due to the inherent trade-off between the two parameters . Nonetheless, Fu et al successfully mitigated this trade-off by incorporating several innovative strategies, resulting in a CO 2 separation membrane with an unprecedentedly high CO 2 flux (2600 GPU) and a CO 2 /N 2 selectivity of 788 .…”

Process Operability Analysis of Membrane-Based Direct Air Capture for Low-Purity CO2 Production

“…The upper bound for selectivity exceeds literature values; however, as facilitated transport membranes such as the PIL-IL/GO membranes continue to be developed, attaining such high selectivities in the near future is not unreasonable to expect. In all cases, the CO 2 /O 2 selectivity was maintained to be 0.25 × CO 2 /N 2 selectivity, to closely model the behavior of the reported facilitated transport membrane by Lee et al In future work, the variation of the CO 2 /O 2 selectivity with the CO 2 permeance must be considered to match more realistic scenarios.…”

“…This work describes a hollow-fiber membrane-based process design that extracts CO 2 from ambient air and concentrates it to an ≈5% permeate CO 2 level. The base case of this simulation work assumes the hollow fiber properties to be equivalent to those of the PIL-IL/GO-facilitated transport membrane described by Lee et al, i.e., CO 2 permeance nominal value of 2100 GPU (7.0350 × 10 –7 kmol·m –2 ·s –1 ·kPa –1 ) and CO 2 /N 2 and CO 2 /O 2 selectivities of 1100 and 265, respectively, for the first membrane module and CO 2 permeance of 128 GPU (4.288 × 10 –8 kmol·m –2 ·s –1 ·kPa –1 ) and CO 2 /O 2 and CO 2 /N 2 selectivities of 17 and 68, respectively, for the second module. Using the information from the base case, a process operability analysis is performed to assess the impact of the effects of input parameters (membrane properties, module surface areas, and feed flow rate) on the final CO 2 purity, CO 2 recovery, and energy consumption.…”

“…However, one could consider different geometries for different stages, but such optimizations are beyond the scope of this paper. The membrane intrinsic properties (e.g., permeance and selectivity) in Table are assumed to be the same as reported by Lee et al It must be noted that this facilitated transport membrane was developed as a flat sheet and has not been reported to be configured into hollow fibers. Therefore, one of the key assumptions in this study is that a thin selective layer of PIL-IL/GO can be coated on a porous support, as reported elsewhere, and the resulting high-performing material can be formatted into hollow fibers.…”

“…Hollow fiber configurations provide high surface area-tovolume ratios and millions of such fibers can be easily packed into modules, thus enabling high-productivity separation devices. The membrane properties noted by Lee et al 17 are used in the base case scenario of this hollow fiber membrane simulation. The analysis of the proposed process is then performed by employing a process operability framework.…”