不同有机胺修饰MCM-41的CO_2吸附性能和热稳定性

CO_2 adsorption properties and thermal stability of different amine-impregnated MCM-41 materials

将乙二胺(EDA,60 g/mol)、四乙烯五胺(TEPA,189 g/mol)和两种聚乙烯亚胺600(PEI600g/mol;PEI1800g/mol)分别负载在MCM-41上制备氨基功能化介孔材料,研究其对CO2的吸附性能和热稳定性。结果表明,除了EDA-MCM41,其他三种材料随着胺分子量增大CO2吸附性能下降,但是热稳定性却有所提高,其中,TEPA-MCM41的吸附容量最大,达到2.7 mmol/g。同时发现,乙二胺在制备过程中随溶剂挥发而难以完全负载在MCM-41上。在纯N2气氛和再生温度100℃条件下,经10次循环实验后,TEPA-MCM41的吸附能力下降了7.4%,而PEI600-MCM41和PEI1800-MCM41吸附能力保持不变,且质量变化在1%以内,表现出良好的再生稳定性。采用80%CO2/20%N2对吸附饱和的材料进行再生,四种材料的再生温度将提高到160℃以上,高分子量PEI600-MCM41和PEI1800-MCM41相比于TEPA-MCM41具有更好的热稳定性。

The adsorption properties of CO2 on MCM-41 mesoporous materials impregnated with ethylenediamine （EDA）, tetraethylenepentamine （TEPA） and two kinds of polyethylenimines （PEI600 and PEI1800）, respectively, were studied with mass spectrometry （ MS ） and thermogravimetry （TG） techniques. The sample obtained by impregnating EDA （EDA-MCM-41） showed a low CO2 adsorption capacity due to the ready volatilization of EDA, while those samples prepared by TEPA （TEPA-MCM-41）, PEI600 （PEI600- MCM-41 ） or PEI1800 （PEI1800-MCM-41） exbibit higher adsorption capacity and thermal stability although the adsorption capacity decreased with increasing molecular weight of amines. A maximum CO2 adsorption capacity of 2.7 mmol/g was achieved on the TEPA-MCM-41 with 40% TEPA. When this sample was regenerated at 100 ℃（2 under pure nitrogen atmosphere, its CO2 adsorption capacity was decreased by 7.4% after ten recycles in contrast to less than 1% for both PEI600-MCM-41 and PEI1800-MCM-41. However, when the regeneration atmosphere was changed to 80% CO2/20% N2, the regeneration temperature should be be increased to more than 160 ℃12 for all the samples despite that PEI-MCM-41 showed high thermal stability than TEPA-MCM-41.