Application of mesoporous activated alumina functionalized with diethanolamine (DAAB) for selective
adsorption of carbon dioxide (CO2) from its mixture with nitrogen gas was investigated. Morphological
structure, elemental composition and the functional groups present in the DAAB were analyzed using
the scanning electron microscopy; energy dispersive X-ray technique and Fourier transform infrared
analysis. Investigation of effect of the gas mixture feed flow rate, column adsorption temperature, DAAB
bed height and concentration of CO2 in the feed stream revealed that 90 mL/min, 35 C, 3 g and 10% of
CO2, respectively were the optimum operating conditions for the highest adsorption capacity of
55.94 mg/g. The DAAB multi-cycle CO2 adsorption test revealed that it can be reused successfully for
about 13 times with high sorption capacity. The DAAB is a promising adsorbent that can be used to
capture CO2 pollutant molecules.