Application of conventional polymeric membranes in CO2 separation processes are limited by the existing trade-off between permeability and selectivity represented by the renowned upper bound. Addition of porous nanofillers in polymeric membranes is a promising approach to transcend the upper bound, owing to their superior separation capabilities. Porous nanofillers entice increased attention over nonporous counterparts due to their inherent CO2 uptake capacities and secondary transport pathways when added to polymer matrices. Infinite possibilities of tuning the porous architecture of these nanofillers also facilitate simultaneous enhancement of permeability, selectivity and stability features of the membrane conveniently heading in the direction towards industrial realization. This review focuses on presenting a complete synopsis of inherent capacities of several porous nanofillers, like metal organic frameworks (MOFs), Zeolites, and porous organic frameworks (POFs) and the effects on their addition to polymeric membranes. Gas permeation performances of select hybrids with these three-dimensional (3D) fillers and porous nanosheets have been summarized and discussed with respect to each type. Consequently, the benefits and shortcomings of each class of materials have been outlined and future research directions concerning the hybrids with 3D fillers have been suggested.

Membrane technology has the potential to be an eco-friendly and energy-saving solution for the separation of CO2 from different gaseous streams due to the lower cost and the superior manufacturing features. However, the performances of membranes made of conventional polymers are limited by the trade-off between the permeability and selectivity. Improving the membrane performance through the addition of nanofillers within the polymer matrix offers a promising strategy to achieve superior separation performance. This review aims at providing a complete overview of the recent advances in nanocomposite membranes for enhanced CO2 separation. Nanofillers of various dimensions and properties are categorized and effects of nature and morphology of the 0D to 2D nanofillers in the corresponding nanocomposite membranes of different polymeric matrixes are discussed with regard to the CO2 permeation properties. Moreover, a comprehensive summary of the performance data of various nanocomposite membranes is presented. Finally, the advantages and challenges of various nanocomposite membranes are discussed and the future research and development opportunities are proposed.

Nanocellulose is a promising and sustainable bio-based nanomaterial due to its excellent mechanical properties, biocompatibility, natural abundance, and especially its high aspect ratio.Interest in applying nanocellulose as nanofillers in membrane fabrication has been growing rapidly in recent years. In the present work, nanocellulose crystals (CNC) and nanocellulose fibers (CNF) were incorporated into polyvinyl alcohol (PVA) to prepare evenly dispersed nanocomposite. The resultant nanocomposite materials containing up to 80 wt% of nanocellulose were coated as defectfree, thin-film-composite (TFC) selective layers onto hollow fiber membrane substrates via dipcoating for efficient CO 2 capture. TGA, FTIR, XRD, STEM, SEM, and humid mixed gas permeation test were used to evaluate the nanocomposite materials and the membranes. The resultant PVA/CNC nanocomposite membranes exhibit both higher CO 2 permeance and CO 2 /N 2 selectivity compared to the PVA/CNF membranes and the neat PVA membranes. The addition of CNC showed more positive effects on the CO 2 permeation compared to CNF. Under optimized conditions, CO 2 permeance of 672 GPU with a CO 2 /N 2 selectivity of 43.6 was obtained with a PVA/CNC membrane. Excellent long-term stability of the membrane was also documented within a period of up to one year. The interface between the polymer phase and the charged nanocellulose fibers is believed to form fast gas transport channels at humid state and thus enhances CO 2 permeation. industrial interests, and the materials used are sustainable, low cost and easy to process. This work may open a new window for the utilization of bio-based materials from nature for the fabrication of CO 2 separation membranes.

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A class of “green” hybrid membranes composed of nanocellulose and an ionic liquid exhibits exceptional separation properties arising from a humidity-responsive size-exclusive “gate” that allows selective CO2 permeation.