功能化硅基介孔材料的合成及其CO_2吸附性能

Synthesis of Functionalized Mesoporous Silica and Its Performance for CO_2 Adsorption

以传统的阳离子表面活性剂十六烷基三甲基溴化铵(CTAB)和阴离子水溶性聚合物聚丙烯酸钠(NaPAA)为复合模板剂,在室温下合成了新型硅基介孔材料;选用聚乙烯亚胺(PEI)和硝酸镁(Mg(NO_3)_2·6H_2O)对其进行改性,制备了PEI和MgO改性硅基介孔材料。采用X射线衍射、N_2吸附-脱附、静态体积法和程序升温脱附手段考察了该硅基介孔吸附材料的结构和CO_2吸附性能。结果表明,该硅基介孔材料具有较大的比表面积和孔体积以及均匀的孔道结构,可以使改性剂很好地分散在其孔道内,PEI和MgO改性的硅基介孔吸附材料对CO_2的吸附能力大大增强。在298K下,PEI负载质量分数为16.7%的PEI改性硅基介孔材料对CO_2的吸附量最大,达到0.98 mmol/g;MgO改性的硅基介孔材料在MgO负载质量分数为20%时,对CO_2的吸附量最大。

Mesoporous silica was synthesized with the mixture of cationic cetyltrimethylammoium bromide （CTAB） and anionic water-soluble sodium polyacrylate （NaPAA） as template at room temperature, and was further modified with polyethyleneimine （PgI） or magnesium nitrate to get PEI-loaded or MgO-loaded mesoporous silica adsorbents for COe. The physical properties and COe adsorption capacity of as-prepared adsorbents were determined by X-ray powder diffraction （XRD）, Nz adsorption-desorption, C（）2 static adsorption and temperature programmed desorption. The results indicated that the mesoporous silica possessed high specific surface area, large pore volume and uniform pore structure. The modifiers of PEI and MgO were uniformly dispersed in the channels of the modified mesoporous silica. The adsorption capacities of the PEI-loaded and MgO- loaded mesoporous silica adsorbents for CO2 were enhanced significantly. The highest COe adsorption capacity of PEI-loaded mesoporous silica was achieved at 16.7% PEI loading, while an MgO loading of 20% gave the MgO-loaded mesoporous silica the highest CO2 adsorption capacity.