CO2 adsorption in amine-grafted zeolite 13X

https://doi.org/10.1016/j.apsusc.2014.06.164

“Taking into account the results obtained from the characterization of the pristine and grafted adsorbents, the samples ZX, ZX0.2 and ZX10 were chosen to be assessed for CO₂ adsorption (Fig. 6). As expected, the isotherms of conventional ZX supports show a sharp increase in CO₂ uptake at low partial pressures reaching a constant plateau at higher pressures (typical of strongly favorable isotherms).”

“Fig. 6. Adsorption isotherms of CO₂ in ZX, ZX0.2 and ZX10 at 298 K (a) and 348 K (b).”

“Functionalized adsorbents show different trends regarding their CO₂ adsorption isotherms as compared to the pristine zeolite 13X, some of which had already been previously observed [4]. ZX0.2 and ZX10 presented a lower CO₂ uptake in the whole pressure range under study as compared to ZX. The reduction in textural characteristics can justify the lower CO₂ uptake. However, ZX10 presented two distinct behaviors: CO₂ uptake increases at higher temperatures (348 K) and, at high pressures, CO₂ adsorbed concentration keeps rising steadily. These features are consistent with the hypothesis of CO₂ chemisorption, as suggested in XPS and FTIR results previously shown.”