Adsorption Capacity of Carbon Dioxide on Amine Modified Mesoporous Materials with Larger Pore Sizes

Mesoporous silica SBA-15-like materials with large pores were synthesized using tri-block copolymer P123 as a structure-directing agent, tetramethoxysilane as the silicon source, and different organic solvents as swelling agents. The resulting materials were characterized by powder X-ray diffraction (XRD), N2 adsorption-desorption, scanning electron microscopy (SEM), and Fourier transform infrared (FTIR) spectroscopy. The results showed that the introduction of swelling agents effectively enlarged the pore diameter and pore volume of the SBA-15 materials, and pore swelling with isooctane was larger than that with CCl4. When modified with tetraethylenepentamine (TEPA), all of these composite materials exhibited excellent adsorption capacities for CO2. The adsorption capacity of CO2 was independent of the pore structure, if the template was removed before modification with TEPA. By contrast, the adsorption capacity increased with the pore diameter when the as-synthesized mesoporous material was modified with TEPA. The effects of temperature and pressure on the CO2 adsorption capacity were investigated using adsorption isotherms and CO2 temperature-programmed desorption (TPD). With CO2 adsorption at higher temperature, the composite materials showed different adsorption capacities with pressure variation. As a result, the adsorption and separation of CO2 on these TEPA modified mesoporous materials in ambient air flow can be realized via pressure swing adsorption. [Article] doi: 10.3866/PKU.WHXB201202071 www.whxb.pku.edu.cn 物理化学学报(Wuli Huaxue Xuebao) Acta Phys. -Chim. Sin. 2012, 28 (4), 985-992 April Received: September 1, 2011; Revised: January 9, 2012; Published on Web: February 7, 2012. ∗Corresponding author. Email: ychun@nju.edu.cn; Tel: +86-25-83686501. The project was supported by the National High-Tech Research and Development Program of China (863) (2008AA06Z327), Fundamental Research Funds for the Central Universities, China (1116020503), and Testing Fund of Nanjing University, China (0205001330). 国家高技术研究发展计划项目(863) (2008AA06Z327),中央高校基础研究基金(1116020503)及南京大学开放测试基金(0205001330)资助 C Editorial office of Acta Physico-Chimica Sinica 985 Acta Phys. -Chim. Sin. 2012 Vol.28