N-doped mesoporous alumina for adsorption of carbon dioxide

摘要

N-doped mesoporous alumina has been synthesized using chitosan as the biopolymer template. The adsorbent has been thoroughly investigated for the adsorption of CO_2 from a simulated flue gas stream (15% CO_2 balanced with N_2) and compared with commercially available mesoporous alumina procured from SASOL, Germany. CO_2 adsorption was studied under different conditions of pretreatment and adsorption temperature, inlet CO_2 concentration and in the presence of oxygen and moisture. The adsorption capacity was determined to be 29.4 mg CO_2/g of adsorbent at 55℃. This value was observed to be 4 times higher in comparison to that of commercial mesoporous alumina at a temperature of 55℃. Basicity of alumina surface coupled with the presence of nitrogen in template in synthesized sample is responsible for this enhanced CO_2 adsorption. Adsorption capacity for CO_2 was retained in the presence of oxygen; however moisture had a deteriorating effect on the adsorption capacity reducing it to nearly half the value.