介孔SiO_2吸附CO_2的性能研究

CO_2 capture of three-dimensional worm-hole mesoporous silica

以正硅酸乙酯(TEOS)为硅源,端氨基聚氧化丙烯醚(D2000)为模板剂,在水和乙醇的混合溶液中合成了蠕虫状介孔结构的介孔SiO_2(记为MSU-J)。采用物理浸渍的方法利用四乙烯五胺(TEPA)改性介孔MSU-J。采用红外、N_2吸附/脱附、元素分析表征改性介孔SiO_2。红外测试表明,经过物理浸渍可以将有机胺负载到介孔SiO_2上。N_2吸附/脱附试验表明,经过氨基修饰后,介孔SiO_2的介孔结构没有发生变化,但是介孔的孔容、孔径以及比表面积随着氨基浸渍量的增加而减小。在25℃和45℃,0.1 MPa下的纯CO_2吸附试验表明,氨基改性材料对CO_2吸附效果明显提高。当浸渍量为20%、吸附条件为25℃/0.1 MPa时,吸附量达到最大值138.6mg/g。当氨基含量继续增加时,吸附量反而降低。循环性试验表明,制备的吸附剂具有良好的循环性能,循环使用6次,材料的吸附量下降很少。

Using tetraethoxysilane （TEOS） as the silicone source and amino-terminated poly（propylene oxide） （D2000） as the template the mesoporous silica with three-dimensional worm-hole mesostructure （MSU-J） was prepared in the mixture of water and ethanol. Tetraethylenepentamine （TEPA） was employed to functionalize the MSU-J silica via wet impregnation method. The resultant samples were characterized by FT-IR, N2 adsorption/desorption and elemental analysis. The FI-IR analysis indicated that the organic amine was supported on the mesoprous SiO2. The results of N2 adsorption/desorption tests showed that after modification with amine the mesoporous structure did not change, but the pore volume, pore size and specific area were decreased with increasing the amine impregnation amount. The pure CO2 adsorption tests at 25℃and 45℃, 0.1 MPa revealed that the CO2 capture of amine-modified sample was obviously increased. The sample impregnated with 20%TEPA showed the highest adsorption capacity with the value of 138.6 mg/g at 25℃ and 0.1 MPa. But the capture was decreased when increasing further the amine content. The resultant adsorbent material exhibited satisfactory performance even after six adsorption–regeneration cycles.