Impact of adsorbent carbons and carbon surface conductivity on adsorption capacity of CO2, CH4, N2 and gas separation

Abstract

We have explored the role of pore width, specific surface area, and surface conductivity of nanoporous carbons on their adsorption capacity of CO2, CH4, and N2. Graphene sheets with a pore width of 7.35 Å (522.65 m2/g) and activated carbon (2445.38 m2/g) have been generated using a user-written code and Hybrid Reverse Monte Carlo (HRMC) algorithm. We have numerically shown that the graphene sheets enhance the gas separation properties, i.e., gas separation of CO2 and CH4 from N2 in the binary and ternary mixtures. Impacts of pre-defined charges on C–H bonds in the activated carbon and carbon surface conductivity have also been investigated using the Charge Simulation Method (CSM) algorithm implementation in a user-written parallel GCMC code. Carbon surface conductivity does not change the adsorption capacity and energy and isosteric adsorption enthalpies are very close for both adsorbents. The isosteric heats of adsorption are also compared for the graphene sheets and activated carbons with experimental data in the literature.