Amino-functionalized pore-expanded SBA-15 for CO2 adsorption

作者：Olea A; Sanz Perez E S; Arencibia A; Sanz R; Calleja G^*

来源：Adsorption, 2013, 19(2-4): 589-600.

DOI：10.1007/s10450-013-9482-y

• Pore-expanded SBA-15
• Amino-functionalization
• Diethylenetriamine
• Polyethyleneimine
• Tetraethylenepentamine
• CO2 capture

The adsorption of CO2 on pore-expanded SBA-15 mesostructured silica functionalized with amino groups was studied. The synthesis of conventional SBA-15 was modified to obtain pore-expanded materials, with pore diameters from 11 to 15 nm. Post-synthesis functionalization treatments were carried out by grafting with diethylenetriamine (DT) and by impregnation with tetraethylenepentamine (TEPA) and polyethyleneimine (PEI). The adsorbents were characterized by X-ray diffraction, N-2 adsorption-desorption at 77 K, elemental analysis and Transmission Electron Microscopy. CO2 capture was studied by using a volumetric adsorption technique at 45 A degrees C. Consecutive adsorption-desorption experiments were also conducted to check the cyclic behaviour of adsorbents in CO2 capture. An improvement in CO2 adsorption capacity and efficiency of amino groups was found for pore-expanded SBA-15 impregnated materials in comparison with their counterparts prepared from conventional SBA-15 with smaller pore size. PEI and TEPA-based adsorbents reached significant CO2 uptakes at 45 A degrees C and 1 bar (138 and 164 mg CO2/g, respectively), with high amine efficiencies (0.33 and 0.37 mol CO2/mol N), due to the positive effect of the larger pore diameter in the diffusion and accessibility of organic groups. Pore-expanded SBA-15 samples grafted with DT and impregnated with PEI showed a good stability after several adsorption-desorption cycles of pure CO2. PEI-impregnated adsorbent was tested in a fixed bed reactor with a diluted gas mixture containing 15 % CO2, 5 % O-2, 80 % Ar and water (45 A degrees C, 1 bar). A noteworthy adsorption capacity of 171 mg CO2/g was obtained in these conditions, which simulate flue gas after the desulphurization step in a thermal power plant.

• 出版日期2013-4