CO2 selectivity in CO2:CH4 and CO2:N2 mixtures on carbon microfibers (CMFs) and carbon microspheres (CMSs)

Reyna Ojeda-López, Enrique Vilarrasa-García, Diana C. S. Azevedo, Carlos Felipe, Juan A. Cecilia, Enrique Rodríguez-Castellón

Research output: Contribution to journalArticlepeer-review

6 Scopus citations

Abstract

The CO2 selectivity in CO2:CH4 and CO2:N2 mixtures has been studied in carbon materials; carbon microspheres (CMSs) and carbon microfibers (CMFs). These materials have different morphologies and textural properties but with similar chemical composition, which was demonstrated by SEM, nitrogen adsorption, and XPS techniques. The isosteric enthalpy of adsorption shows that the interaction between the CO2 molecule and CMFs releases a higher energy than CMSs. CMSs have a higher surface area and thus superior CO2 adsorption only at pressures above 6 bar, for example, i) at 323 K and 1 bar, 1.43 mmol CO2 (CMFs) and 0.82 mmol CO2 (CMSs), and ii) at 323 K and 10 bar, 3.24 mmol CO2 (CMFs) and 3.70 mmol CO2 (CMSs). At 1 bar, CMFs is better than CMSs, improving it by 40 %. And at 10 bar, although CMSs adsorb more than CMFs, it is only 14 % more. In addition, CMFs have a higher microporosity, which allows them to exhibit better CO2 selectivity in CO2:CH4 mixtures, even at relatively high pressures (5.4 mmol CO2 / mmol CH4 at 298 K and 1 bar, 4.6 mmol CO2 / mmol CH4 at 323 K and 10 bar). These values are like those reported in the literature for carbon materials synthesized by more complex and expensive methods.

Original languageEnglish
Article number124242
JournalFuel
Volume324
DOIs
StatePublished - 15 Sep 2022

Keywords

  • CH adsorption
  • CO adsorption
  • CO selectivity
  • Carbon microfibers
  • Carbon microspheres
  • Electrospinning

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