Screening of Porous Materials for Toxic Gas Adsorption: Classical Density Functional Approach

A computer-aided method was developed to screen promising toxic gas adsorbents. The method was based on classical density functional theory (CDFT) with molecular models constructed using quantum density functional theory (QDFT). The accuracy of the theory was first examined by comparison to experimental data. Then, the theory was applied to the screening of 6,301 porous materials for the adsorption of eight toxic gases. At low (100 ppmv) and high (1 bar) concentrations, respectively, zeolites and MOFs appear to be the most promising adsorbents for the gases except CO. A universal correlation between the uptake and heat of adsorption exists for most systems, and the few adsorbents that fail to follow this correlation appear to be promising reusable adsorbents. The flexibility effect is considered by molecular dynamics simulations, which plays an important role in the adsorption and might lead to a significant (more than 95%) decrease in the uptake for the favorable adsorbents.