Adsorption may be a potentially attractive alternative to capturing CO 2 from stationary sources in the context of Carbon Capture and Sequestration (CCS) technologies. Activated carbon and zeolites are state-of-art adsorbents which may be used for CO 2 adsorption, however physisorption alone tends to be insignificant at high temperatures. In the present work, commercial adsorbents have been impregnated with monoethanolamine (MEA) and triethanolamine (TEA) in order to investigate the effect of the modified surface chemistry on CO 2 adsorption, especially above room temperature. Adsorption isotherms for CO 2 , N 2 and CH 4 were measured in a gravimetrically system in the pressure range of UHV to 10 bar, at 298 and 348 K for activated carbon and zeolite 13X supports. The adsorbed concentration of CO 2 was significantly higher than those of CH 4 and N 2 for both adsorbents in the whole pressure range studied, zeolite 13X showing a remarkable affinity for CO 2 at very low pressures. However, at 348 K, the adsorbed concentration of CO 2 decreases significantly. The supports impregnated with concentrated amine solutions and dried in air suffered a detrimental effect on the textural properties, although CO 2 uptake became much less susceptible to temperature increase. Impregnations carried out with dilute solution followed by drying in inert atmosphere yielded materials with very similar textural characteristics as compared to the parent support. CO 2 isotherms in such materials showed a significant change with similar capacities at 348 K as compared to the original support at 298 K in the case of activated carbons. The impregnated zeolite showed a decrease in adsorbed phase concentration in low pressures for a given temperature, but the adsorbed amount also seemed to be less affected by temperature. These results are promising and indicate that CO 2 adsorption may be enhanced despite high process temperatures (e.g. 348 K), if convenient impregnation and drying methods are applied.

The present work presents the design, assembly and experimental validation of a microcalorimetric device coupled to a volumetric adsorption setup applied to the characterisation of adsorbents for carbon dioxide (CO2) capture. Three adsorbents were evaluated for CO2 adsorption at 273 K in the pressure range of vacuum to 101 kPa. The data for CO2 on zeolite 13X agreed well with the available data reported in the literature, thus validating the device, which also provided reproducible results with an activated carbon sample. For the amine‐modified zeolite, the differential enthalpy at lower coverage was increased by a factor of 1.7 as compared to the zeolite matrix. This points out to the potential of such technique to characterise heterogeneities introduced by amine impregnation. However, the adsorption uptake was decreased by factor of 2.7 at 101 kPa. This fact suggests that amino groups may be blocking some physisorption sites, leading to restricted chemisorption on the outer surface. Thus, the main novelty of this study is the simultaneous measurement of adsorption isotherms and respective differential enthalpy curves for amine‐impregnated adsorbents, which may be considered a fingerprint of the modified surface chemistry. This work has been carried out in the framework of a cooperation project between three South American universities and is part of the effort to develop and fully characterise adsorbent materials intended for CO2 capture. © 2012 Canadian Society for Chemical Engineering