氨基改性MIL-101(Cr)用于CH4/CO2吸附分离的研究

摘要

Amine-functionalized MIL-101 (Cr) adsorbents were prepared by impregnation method and their crystal structure and properties were characterized by XRD, N2 adsorption and desorption, FT-IR and TG. The adsorption capacities of CO2 and CH4 on amine-functionalized MIL-101 (Cr) adsorbents were measured under 298K and 101.3kPa. The results showed that the interaction strength of amine-functionalized MIL-101 (Cr) with carbon dioxide was greatly increased, which improved the adsorption capability of CO2 and separation performance for CO2/CH4, and for the amine-functionalized adsorbent MIL-101-PEI-70 with a mass ratio of PEI to MIL-101 (Cr), the adsorption capacity of carbon dioxide was improved by 76%, from 50.55cm3/g to 89.43cm3/g, while the adsorption capacity of methane decreased by 44%, from 10.62cm3/g to 5.91cm3/g. The ideal adsorbed solution theory (IAST) model was used to predict the adsorption separation of CO2 over CH4, and the resulted indicated the adsorption selectivity for CO2 increased from 11 of unmodified MIL-101(Cr) to 255 of MIL-101-PEI-70. The adsorbents could be regenerated under mild conditions of 80℃and vacuum.%采用浸渍法合成氨基改性金属有机骨架材料MIL-101(Cr)，并用XRD、N2吸附和脱附、FT-IR和TG等表征手段考察材料的结构和性能，测试氨基改性MIL-101(Cr)吸附剂在101.3kPa、25℃下的CO2、CH4吸附量。结果表明，氨基改性后的MIL-101(Cr)与CO2作用力显著增强，提高了CO2吸附量和CO2/CH4分离性能。 PEI/MIL-101(Cr)质量比为70的MIL-101-PEI-70吸附剂的CO2吸附量由50.55cm3/g增加到89.43cm3/g，提升76%，而CH4吸附量由10.62cm3/g下降为5.91cm3/g，降低44%，用理想吸附溶液理论预测其CH4/CO2吸附选择性由11增加到255。吸附CO2后的吸附剂可在80℃、真空下再生，脱附条件温和。