Comparative Study of the Adsorption Equilibrium of CO₂on Microporous Commercial Materials at Low Pressures

Abstract

The adsorption of CO2 on several microporous materials has been measured at various temperatures (263, 273, 283, and 293 K) over a wide range of pressures. The porous materials studied were three zeolites (5A, 13A, and 13X), two metal–organic frameworks (Basolite A100 and Basolite Z1200), an activated carbon, and two pillared clays (Al-PILC and Zr-PILC). The data obtained were fitted to the Freundlich, Langmuir, and Toth isotherms. Various methods were used to calculate the Henry’s law constants. The values found for the zeolites, which ranged from 8.95 to 36.02 mmol/kPa·g at 273 K, were much higher than those for the metal–organic frameworks, activated carbon, and pillared clays, which ranged from 0.012 to 0.200 mmol/kPa·g at the same temperature. The isosteric heats of adsorption of CO2 on the materials were calculated using the Clausius–Clapeyron equation, and the adsorbent–CO2 affinity was found to increase in the order Z1200 ≈ 13X ≈ 13A < 5A < Zr-PILC < A100 ≈ AC ≈ Al-PILC at low loadings.

Nonlinear Frequency Response measurements of gas adsorption equilibrium and kinetics: New apparatus and experimental verification

“…The obtained value is in good agreement with heats of adsorption for CO 2 /zeolite 5A reported by Tlili et al (2009) (30 kJ/mol) and Garces et al (2013) (40 kJ/mol).…”

High surface area porous carbons produced by steam activation of graphene aerogels

“…It can be seen that there is an obvious increase in carbon dioxide adsorption capacity for SAGA-850 (10.8 wt%), which is comparable to other porous materials under the same conditions. 36,[62][63][64] For comparison, the carbon dioxide uptake capacity of the CGA prepared without steam activation is also given (4.1 wt%), indicating that steam activation is of great importance to the enhancement of carbon dioxide adsorption. Furthermore, carbon dioxide sorption isotherms of all these samples are almost reversible, implying that the uptake of carbon dioxide is essentially via physisorption.…”

Adsorption equilibrium of carbon dioxide on ammonia-modified activated carbon

“…However, a variation of the isosteric heats with the surface loading indicates the existence of different levels of surface energy and heterogeneity of the adsorbent surface (Ning et al, 2012). Figure 6 (Chue et al, 1995;Esteves et al, 2008;Garcés et al, 2013;Himeno et al, 2005;Van Der Vaart et al, 2000). In contrast, OXA-GAC exhibited rather high values of st Q at the low range of loading, which reflects the relatively strong chemical interactions between CO 2 and the basic nitrogen functionalities.…”

“…Because fossil fuels are likely to remain the predominant energy source all over the world, CO 2 emissions must be reduced to mitigate the unfettered release of this greenhouse gas into the atmosphere (Garcés et al, 2013;Siriwardane et al, 2001). As a result, various CO 2 separation techniques, such as liquid solvent absorption, membrane separation, cryogenic separation, and adsorption processes including pressure/vacuum swing adsorption (PSA/VSA) and temperature swing adsorption (TSA), are currently under investigation (Gomes and Yee, 2002;Xu et al, 2002).…”

“…Although reliable experimental equilibrium data for some adsorbates on carbon adsorbents are extensively available in the literature Garcés et al, 2013), as far as we know, very few data have been reported for CO 2 adsorption over ammonia-modified activated carbons under the conditions used here. Furthermore, no studies have been conducted to analyze the CO 2 adsorption isotherms over such adsorbents to fit to a proper isotherm model.…”