A metal-doped flexible porous carbon cloth for enhanced CO2/CH4 separation

Abstract

From a practical perspective, carbon adsorbents are mostly prepared to form functional components from carbon powder by using binders or hot pressing, which results in the degradation of its textural properties. Thus, the flexible activated porous carbon cloths have attracted increasing interest in recent years because these are easier to handle than powder and granular materials when constructing more conformable and efficient membrane device designs. In this work, a metal-doped flexible porous carbon cloth with outstanding CO2/CH4 selectivity was developed. Carbon cloth deposited with spherical porous carbon nanoparticles and doped with nitrogen was prepared from viscose rayon cloth decorated with polypyrrole nanoparticles. Then, this flexible carbon cloth was doped with nickel. Two samples with moderate Ni content (7 and 10 wt%) were used to investigate the fundamental magnetic properties and CO2/CH4 separation performance. These two samples have both antiferromagnetic and ferromagnetic properties, and it is originated from the different ratios of NiO and pure Ni. The Ni (O) contents in the flexible carbon cloth influenced the CO2 and CH4 sorption properties and separation performance as well. Based on the ideal adsorbed solution theory (IAST) model, the developed metal-decorated flexible activated carbon cloth shows 13 times better separation performance than Ni-free sample and achieved CO2/CH4 (1:1) selectivity of 369.5 and 70.7 at 20 and 1 bar, respectively, at 298 K, which is among the highest selectivity values reported for porous carbon materials so far.