Molecular simulation to analyze the influence of ultrafine particles on activated carbon adsorbing low concentration toluene

Abstract

Adsorption is an effective technology to remove the gaseous pollutants. In the actual implementation, the particulate matters (PMs) are firstly filtered to guarantee the adsorption performance of absorbent. However, the PMs cannot be completely removed based on the current state of the art, especially the ultrafine particles. Therefore, in this work, taking activated carbon as an example, the influence of ultrafine particles on its gaseous adsorption performance was detailed investigated. The nanoporous carbon model was proposed and the adsorption of toluene with/without NaCl particles was simulated based on the GCMC (Grand Canonical Monte Carlo) method and MD (Molecular Dynamics) method. The results showed that, with the existence of NaCl, the diffusion coefficient of toluene in the activated carbon was reduced by 27%, the amount of toluene absorbed was reduced by 20.8%–28.6%, and the van der Waals energy was varied in a relative wider range. The favorable adsorption sites were 4.4 Å away from the graphite slices of activated carbon, which was not affected by NaCl particles. This was also verified by the analysis of energy distribution. This study revealed the mechanism of gas-solid coupling mass transfer in the porous materials and would help master the actual adsorption performance of adsorbent.