Rational fabrication of ultramicroporous flexible porous carbon fabrics for efficient capture of CO2 andCO2/N2 and CO2/H2 separation

An innovative flexible nanoporous carbon fabrics were developed for selective capture of CO2 and its separation over N2 and H2 gases. The as developed flexible porous fabrics was fabricated using viscose rayon fabrics coated with various nanocoatings includes phosphorylated cellulose nanocrystals (P-CNC), polyaniline nanofibers (PANI-NFs) and graphene sheets derived from mandarin shell in conjunction with polyvinyl alcohol (PVA). Afterwards, they were carbonized and subsequently chemically activated with green potassium dihydrogen orthophosphate as an activating agent. The developed flexible porous carbon fabrics achieved superior microporosity with specific surface area and total pore volume of 753 m2 g-1 and 0.309 cm3 g-1, respectively. This is in addition to existence of ultramicropores of size 0.61 nm and rich doping with oxygen, nitrogen and phosphorus species, in conjunction with precious metals residues. Besides, their flexibility, easier processability and safe handling properties, they achieved high CO2 uptake of 5.72 and 38.7 wt.% at 1 and 30 bar and room temperature, respectively. This superior CO2 uptake at pre-and post-combustion conditions was ascribed to ultramicropores and high electron density adsorption sites which affords easier adsorption and interaction of CO2 molecules with pore walls. Moreover, the flexible porous fabric records superior removal of CO2 over N2 from flue gas recording separation selectivity of CO2/N2 of 36.5 at 30 bar and room temperature based on uptake ratio. Additionally, they achieved outstanding separation selectivity of CO2 over H2 gas achieving CO2/H2 of 280.