Carbon aerogels in the form of microspheres and their potential application in CO2 adsorption: A thermodynamic and kinetic study
Jessica Carolina Hernández-Galeano, Jarosław Serafin, Liliana Giraldo, Yesid Murillo‐Acevedo, Juan Carlos Moreno‐Piraján
Abstract
• Carbon aerogels were synthesized from resorcinol/phenol formaldehyde in the form of the microsphere , successfully. • The textural and kinetic properties of aerogels were well characterized. • The drying stage provides interesting characteristics to the material. • The best adsorption capacity of CO 2 was 29.6 mmolg −1 at 30 °C up to 50 bars. In this investigation, we conducted the synthesis and characterization of carbon aerogels in microsphere form, utilizing resorcinol, phenol , and formaldehyde in an ethanol medium. The Stöber method was employed to examine the CO 2 adsorption capabilities of these aerogels. A sol-gel polymerization reaction, catalyzed by NH 3 produced a network of crosslinked organic monomers from the initial precursors. Adjustments were made to precursor concentrations and ammonia proportions to investigate the influence of phenol and catalyst quantity on the resultant material. The characterization involved scanning electron microscopy with energy dispersive X-ray spectroscopy, N 2 and CO 2 adsorption isotherms, thermogravimetric analysis, X-ray diffraction powder, Boehm titration, and CO 2 adsorption capacity at elevated pressures up to 50 bars. The BET surface area values ranged from 532 to 775 m 2 g −1 , with the highest achieved in the SDA sample, synthesized with an 80:20 resorcinol to phenol ratio. The optimal CO 2 sorption value of 29.6 mmolg-1 at 30 °C up to 50 bars was observed in the TDA sample. The catalyst quantity influenced the size of carbonized spheres, with a larger diameter observed when phenol was included as a precursor. Adsorption studies for the best-synthesized aerogel involved two and three-parameter kinetic and thermodynamic models.