Flexible carbon sieve based on nanoporous carbon cloth for efficient CO2/CH4 separation

Novel and efficient flexible carbon sieves for landfill gas and biogas upgrading are developed. Various carbon cloths and activated ones have been developed from different carbon precursors (cotton, viscose rayon and blend furniture textiles). In order to enhance the charring effect and nitrogen elements doping, the polypyrrole nanoparticles (PNP) were decorated on the textile fabrics before carbonization, and activation process producing a flexible double sieve. In case of the viscose rayon cloth, a chitosan layer was additionally coated and carbonized, resulting in a double carbon sieve with unique morphology and rich with nitrogen. These developed flexible porous carbons were investigated for CO2 uptake and separation in terms of the influence of textile fabric (carbon precursor) type, texture structure, composition and synthesis procedure. The highest textural properties of 1812 m2 g−1 specific surface area and 0.761 cm3 g−1 of total specific pore volume with rich nitrogen and oxygen elemental composition have been achieved. Enhanced and selective adsorption of CO2 over CH4 was exhibited by the flexible sieve developed for natural gas upgrading application, which also exhibited CO2/CH4 selectivity of 8.6 and 17.1 (50:50) at 298 K and 1 and 20 bar, respectively, which is highest among the reported activated carbon cloths and porous materials.