Investigation of CO2 Adsorption on Avocado Stone-Derived Activated Carbon Obtained through NaOH Treatment

Joanna Siemak; Rafał J Wróbel; Jakub Pęksiński; Beata Michalkiewicz

doi:10.3390/ma16124390

Investigation of CO₂ Adsorption on Avocado Stone-Derived Activated Carbon Obtained through NaOH Treatment

Materials (Basel). 2023 Jun 14;16(12):4390. doi: 10.3390/ma16124390.

Authors

Joanna Siemak¹, Rafał J Wróbel¹, Jakub Pęksiński², Beata Michalkiewicz¹

Affiliations

¹ Department of Catalytic and Sorbent Materials Engineering, Faculty of Chemical Technology and Engineering, West Pomeranian University of Technology in Szczecin, Piastów Ave. 42, 71-065 Szczecin, Poland.
² Faculty of Electrical Engineering, West Pomeranian University of Technology, 26 Kwietnia St. 10, 71-126 Szczecin, Poland.

Abstract

Activated carbons were prepared from avocado stone through NaOH activation and subsequent carbonization. The following textural parameters were achieved: specific surface area: 817-1172 m²/g, total pore volume: 0.538-0.691 cm³/g, micropore volume 0.259-0.375 cm³/g. The well-developed microporosity resulted in a good CO₂ adsorption value of 5.9 mmol/g at a temperature of 0 °C and 1 bar and selectivity over nitrogen for flue gas simulation. The activated carbons were investigated using nitrogen sorption at -196 °C, CO₂ sorption, X-ray diffraction, and SEM. It was found that the adsorption data were more in line with the Sips model. The isosteric heat of adsorption for the best sorbent was calculated. It was found that the isosteric heat of adsorption changed in the range of 25 to 40 kJ/mol depending on the surface coverage. The novelty of the work is the production of highly microporous activated carbons from avocado stones with high CO₂ adsorption. Before now, the activation of avocado stones using NaOH had never been described.

Keywords: CO2 adsorption; activated carbons; avocado stone; carbon capture; selectivity.

Grants and funding

This research received no external funding.