Tuning porosity of coal-derived activated carbons for CO2 adsorption

Zhipeng Qie, Lijie Wang, Fei Sun, Huan Xiang, Hua Wang, Jihui Gao, Guangbo Zhao, Xiaolei Fan

Research output: Journal PublicationArticlepeer-review

Abstract

A simple method was developed to tune the porosity of coal-derived activated carbons, which provided a model adsorbent system to investigate the volumetric CO2 adsorption performance. Specifically, the method involved the variation of the activation temperature in a K2CO3 induced chemical activation process which could yield activated carbons with defined microporous (< 2 nm, including ultra-microporous < 1 nm) and meso-microporous structures. CO2 adsorption isotherms revealed that the microporous activated carbon has the highest measured CO2 adsorption capacity (6.0 mmol·g−1 at 0 °C and 4.1 mmol·g−1 at 25 °C), whilst ultra-microporous activated carbon with a high packing density exhibited the highest normalized capacity with respect to packing volume (1.8 mmol·cm−3 at 0 °C and 1.3 mmol·cm−3 at 25 °C), which is significant. Both experimental correlation analysis and molecular dynamics simulation demonstrated that (i) volumetric CO2 adsorption capacity is directly proportional to the ultra-micropore volume, and (ii) an increase in micropore sizes is beneficial to improve the volumetric capacity, but may lead a low CO2 adsorption density and thus low pore space utilization efficiency. The adsorption experiments on the activated carbons established the criterion for designing CO2 adsorbents with high volumetric adsorption capacity. [Figure not available: see fulltext.]

Original languageEnglish
JournalFrontiers of Chemical Science and Engineering
Early online date25 Apr 2022
DOIs
Publication statusPublished Online - 25 Apr 2022
Externally publishedYes

Keywords

  • CO adsorption
  • coal-derived activated carbons
  • molecular dynamics
  • porosity

ASJC Scopus subject areas

  • Chemical Engineering (all)

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