Poster De Conférence Année : 2025

Nitrogen-enriched activated carbons for the capture and separation of CO2

Résumé

As carbon dioxide (CO2) is one of the main greenhouse gases, the increase in its concentration in the atmosphere leads to global warming. For this reason, numerous researches are presently focused on CO2 separation from industrial gases in the post-combustion process. In this work, nitrogen-enriched Activated Carbons (ACs) with nitrogen content up to 10 wt.% were synthesized in two successive steps in the same furnace: (i) pyrolysis (10K.min-1, 1173K, N2, 200 mL.min-1) of nitrogen-rich precursors: powder and lyophilized chitosan beads (7 wt.% N), coffee grounds (3 wt.% N) and polyacrylonitrile powder (26 wt.% N) and (ii) ammonia gasification activation at 1173K (NH3 flow: 30-36 mg.min-1, activation time: 15-120 min). The physisorption isotherms at 77K of N2 and H2 indicated that the synthesized ACs are mainly microporous, and the BET areas are in the range from 325 to 1390 m².g-1. Adsorption capacities of ACs were studied at three different temperatures 273K, 298K and 323K. The amount of CO2 physisorbed at 1 bar ranged from 1.79 to 2.98 mmol/g at 298K. The calculated isosteric adsorption heat shows stronger interactions between CO2 and the surface groups of ACs (22.07-31.18 kJ.mol-1 at 1 bar), and weak interactions between N2 and the surface groups of ACs (10.35-20.04 kJ.mol-1 at 1 bar). To assess the ability of ACs to select CO2 over N2, the CO2/N2 selectivity (15% vol. of CO2) was calculated using the pure gases’ adsorption isotherms and the Ideal Adsorbed Solution Theory (IAST) model. At 298K, CO2/N2 selectivity reaches values between 24 and 110. ACs from coffee grounds activated for 60, 90 and 120 min exhibit higher selectivity attributed to the optimal balance between textural properties and surface groups. To better understand this behavior at 298K, Principal Component Analysis (PCA) and Partial Least Squares regression (PLS regression), statistical methods were used. They showed that the ultra-micropore volume, the amount of CO2 adsorbed, and the impurities present in ACs influence the CO2/N2 selectivity at 298K. Furthermore, energy dispersive X-ray spectroscopy showed that the impurities likely to influence selectivity at T>298K could be minerals containing Mg, P, Ca, and K.

Domaines

Fichier principal
Vignette du fichier
Poster_journee_chim_durable.pdf (1.43 Mo) Télécharger le fichier
Origine Fichiers produits par l'(les) auteur(s)
Licence

Dates et versions

hal-05406062 , version 1 (09-12-2025)

Licence

Identifiants

  • HAL Id : hal-05406062 , version 1

Citer

Kouassi Fabrice N'Gole, Rafael Morales-Ospino, L Reinert, Bernard David, Nicolas Vincent, et al.. Nitrogen-enriched activated carbons for the capture and separation of CO2. 3rd SUSTAINABLE CHEMISTRY DAY, Nov 2025, Strasbourg, France. ⟨hal-05406062⟩
494 Consultations
178 Téléchargements

Partager

  • More