五乙烯六胺改性金属有机骨架材料MIL-101(Cr)对CO_2的吸附性能

采用溶剂热法合成金属有机骨架材料MIL-101(Cr),用回流法将五乙烯六胺(PEHA)负载到MIL-101(Cr)孔道中的不饱和金属位点上,使用扫描电镜、粉末X射线衍射、氮气物理吸附、元素分析和傅里叶变换红外光谱等表征手段考察材料的结构和形貌,测试氨基改性前后的MIL-101(Cr)在25℃、不同压力下对CO_2的吸附效果。结果表明,负载0.24 m L五乙烯六胺后的MIL-101(Cr)对CO_2的吸附效果最好,在25℃、常压下对CO_2的饱和吸附量可达58.944 mg/g,相比未负载五乙烯六胺的MIL-101(Cr)吸附量(CO_2饱和吸附量为44.208 mg/g)增加了33%。随着吸附压力的增加,MIL-101(Cr)和0.24PEHAM IL-101(Cr)对CO_2的饱和吸附量逐渐增加,当吸附压力为1.1 MPa时,两者的吸附量分别为1 147.59和1 256.74 mg/g,表明该类材料在高压下对CO_2有着良好的吸附效果。

Performance of pentaethylenehexamine modified MIL-101(Cr) metal-organic framework in CO2 adsorption

The metal-organic framework MIL-101(Cr) was synthesized via hydrothermal process and then modified with pentaethylenehexamine (PEHA) through refluxing in ethanol. Various measures such as SEM, XRD, N₂ sorption, Elemental analysis and FT-IR were used to characterize the structure, morphology and properties of PEHA-grafted MIL-101(Cr). Meanwhile, the performance of PEHA-grafted MIL-101(Cr) in CO₂ adsorption was investigated under 25℃. The results illustrate that the loading of PEHA in MIL-101(Cr) can conspicuously enhance the CO₂ adsorption capacity. PEHA-grafted MIL-101(Cr) with a PEHA loading of 0.24 mL exhibits the highest capacity for CO₂ adsorption; the adsorption capacity reaches 58.944 mg/g at 25℃ and atmospheric pressure, which is 33% higher than that of the unmodified MIL-101(Cr) (44.208 mg/g). In addition, the CO₂ adsorption capacities on both MIL-101(Cr) and PEHA-MIL-101(Cr) are greatly enhanced by increasing pressure, reaching 1 147.59 and 1 256.74 mg/g at 1.1 MPa, respectively. These results suggest that PEHA-modified MIL-101(Cr) could be a good candidate adsorbent for CO₂ capture at high pressure.