Synthesis, Characterization and CO2 Adsorption of Mesoporous Composite Materials

• Main Authors: Chen, Yu-Chun, 陳俞君
• Other Authors: Chen, San-Yuan
• Format: Others
• Language: zh-TW
• Published: 2010
• Online Access: http://ndltd.ncl.edu.tw/handle/98330823884898033111

碩士 === 國立交通大學 === 材料科學與工程學系 === 98 === This work focuses on developing a series of mesoporous CaO-based adsorbents for CO2 capture at high temperature. First, mesoporous CaO/SBA-15 composites have been successfully synthesized by wet impregnation using SBA-15 and ion-exchange method with the SBA-15-COOH as the support. The composites undergo calcination at 800℃. These mesoporous CaO/SBA-15 composites have been characterized by XRD, N2 adsorption-desorptgion isotherms, TEM and CO2 adsorption capacity by TGA at 450~650°C. The mesoporous CaO/SBA-15 by impregnation show CaO in the channels and aggregation on the external surface of SBA-15. The CaO/SBA-15 by ion-exchange method have more CaO in the channels. A CO2 adsorption capacity as high as 16.32% of adsorbent was obtained for S15-CaO-3 adsorbent at 650 °C, equal to 100.74% of CaO, with a CaO/SBA-15 ratio of 1/5. The CO2 adsorption mechanism was investigated by adsorption kinetics. Second, a series of mesoporous Ca-Al mixed oxide composites with Ca/Al ratios of 3 and 7 have been synthesized through homogenous decomposition of urea under hydrothermal conditions and subsequent calcination at 600℃. These mesoporous Ca-Al mixed oxides have been characterized by XRD, N2 adsorption-desorptgion isotherms, TEM and CO2 adsorption capacity and cycles by TGA at 300~700°C. At 150℃, Ca2+ and OH- form Ca(OH)2 and CaCO3 on theγ-Al2O3 surface. The calcined samples showed that Ca2+ was introduced into the mesoporous γ-Al2O3 support to form the mesoporous Ca-Al mixed oxides. The mesoporous Ca-Al oxides revealed a high CO2 adsorption capacity and a fast CO2 adsorption rate. The mesoporous Ca-Al oxides using high base concentration have a better reversibility of adsorption/desorption cycles. The Ca-Al oxides provides a stable framework inhibiting deactivation of Ca(OH)2.