# Single-Component Adsorption Equilibria of CO2, CH4, Water, and Acetone on Tapered Porous Carbon Molecular Sieves

## TL;DR

This paper studies how different gases like CO2 and CH4 stick to specially designed carbon materials, comparing them to another carbon type called BPL.

## Contribution

The study introduces tapered porous carbon molecular sieves with enhanced CO2 adsorption capacity compared to BPL carbon.

## Key findings

- Tapered CMSs showed higher CO2 adsorption than BPL carbon, especially Carboxen 1005 due to ultramicropores.
- BPL carbon had higher acetone uptake due to stronger interactions from higher oxygen content.
- Adsorption heats confirmed the order of CO2, CH4, and water adsorption on the materials.

## Abstract

Engineered carbon
molecular sieves (CMSs) with tapered
pores, high
surface area, and high total pore volume were investigated for their
CO2, CH4, water, and acetone adsorption properties
at 288.15, 298.15, 308.15 K, and pressures of <1 bar. The results
were compared with BPL carbon. The samples exhibited higher adsorption
capacity for CO2 compared to BPL carbon, with Carboxen
1005 being the highest due to the presence of ultramicropores (pores
smaller than 0.8 nm). Similar observations were made for CH4 except at 288.15 K. Although the CMSs exhibited higher hydrophobicity
than BPL carbon, the latter had the highest acetone uptake for all
investigated temperatures due to its higher oxygen content, which
facilitates stronger interactions with polar VOC molecules. Heats
of adsorption were calculated using the Clausius–Clapeyron
equation after fitting the isotherms with the dual-site Langmuir–Freundlich
model, and results largely corroborated the order of adsorption capacities
of CO2, CH4, and water on the carbon materials.