Carbon Capture from wet vapors

TL;DR

This study uses molecular dynamics to explore how mixed CO2-water vapors adsorb on graphene, revealing that moisture can enhance CO2 capture efficiency and influence water clustering, with implications for designing better carbon capture materials.

Contribution

It provides new insights into the molecular mechanisms of CO2 and water vapor adsorption on graphene, highlighting the effects of humidity on adsorption efficiency and clustering behavior.

Findings

CO2 adsorbs more strongly and rapidly than water.

Wet vapors increase CO2 uptake below 375 K.

Graphene flakes inhibit large water cluster formation.

Abstract

We present molecular dynamics simulations of the adsorption of mixed CO2-water vapors on a graphene flakes substrate, a model inspired by the microporous structure of activated carbons. Adsorption strength is quantified through a reduced energy measure that avoids ambiguities associated with defining adsorption regions. We find that CO2 adsorbs more strongly and more rapidly than water across all temperatures studied. Adsorption from wet vapors was observed to result in higher CO2 uptake compared with dry vapors at temperatures below 375 K. At intermediate temperatures, water molecules were seen to form clusters that interact with both the substrate and CO2, potentially promoting CO2 adsorption. Additionally, we observe that the GF substrate inhibits the formation of large water clusters, altering water aggregation dynamics near the surface. These findings highlight a cooperative adsorption mechanism in humid environments and suggest that graphene-flakes-based materials may perform effectively for carbon capture under realistic, moisture-containing conditions.