Adsorption of CO2 with tetraethylammonium glycine ionic liquid modified alumina in the Rotating Adsorption Bed

Abstract

CO2 capture and reuse have become the crucial task for controlling severe climate changes. Based on the practical application problems related to high viscosity of the ionic liquids (ILs) in the CO2 absorption process, the new adsorbent was obtained by loading the tetraethylammonium glycine (N2222Gly) on millimeter-scale microspheres of alumina (Al2O3) with ultrasonic impregnation-filtration method in this text. The results shown that the N2222Gly was successfully and uniformly loaded on the surface and pore structure of the Al2O3 by the electrostatic interaction between glycine anion and the positively charged Al2O3 interface. The prepared adsorbent (N2222Gly-Al2O3) were filled in the Rotating Adsorption Bed (RAB), and a rapidly updated gas-solid interface area was formed when the RAB was rotating under the drive of the motor. Under the rotating dynamic environment, more active sites of N2222Gly-Al2O3 were exposed to CO2 and the mass transfer effect between gas-solid was effectively enhanced. The adsorption capacity in the RAB was equal to 15.94 mg·g−1, and was about 4.63 mg·g−1 higher than in the fixed bed. In addition, the RAB showed a seductive strengthening effect with the decrease in adsorption capacity of only 14.5% after six desorption operations (much less than the 30.5% decrease in the fixed bed). Interestingly, as a new type of adsorption device, the RAB enhanced the internal and external diffusion rates of the adsorption process, providing a new idea for the effective adsorption of CO2 at low partial pressure with presence of the N2222Gly-Al2O3.