富氮多级孔炭材料的制备及其吸附分离CO2的性能

使用新型含氮聚合物席夫碱为炭源, SBA-15为模板,通过纳米铸型法原位合成微孔-中孔-大孔串联的多级孔富氮炭材料.材料的比表面积为752 m²·g^-1,孔容0.79 cm³·g^-1; X光电子能谱分析表明炭材料中的氮含量高达7.85%(w).将所制备的多孔炭材料应用于CO₂的吸附分离,发现炭材料的微孔发挥主导作用,表面氮掺杂发挥辅助作用.在两者的协同作用下, CO₂吸附量在常压、273 K下可达97 cm³·g^-1, CO₂/N₂和CO₂/CH₄的分离比(摩尔比)分别为7.0和3.2,低压亨利吸附选择性分别为23.3和4.2.采用Toth模型对单组分平衡吸附进行拟合,并根据理想溶液吸附理论(IAST)预测双组分CO₂/N₂和CO₂/CH₄混合气体的分离选择性分别为40和18.

Nitrogen-Enriched Hierarchical Porous Carbon for Carbon Dioxide Adsorption and Separation

Hierarchical nitrogen-enriched porous carbon containing micropores, mesopores, and macropores were prepared by a nanocasting pathway using a Schiff base precursor and SBA-15 as the hard template. The specific surface area and pore volume of the obtained porous carbon are 752 m²·g^-1 and 0.79 cm³·g^-1, respectively. The nitrogen content is as high as 7.85% (w). The porous carbon shows a CO₂ capacity of 97 cm³·g^-1 at ambient pressure and 273 K. The CO₂/N₂ and CO₂/CH₄ separation ratios (molar ratios) are accordingly 7.0 and 3.2, and the Henry's low pressure selectivities are 23.3 and 4.2, respectively. CO₂ adsorption tests confirmed that the micropores play a dominant role and nitrogen-containing functional groups play a synergistic role. The predicted ideal adsorbed solution theory (IAST) selectivities of the two-component mixed stream are 40 (CO₂/N₂) and 18 (CO₂/CH₄) by Toth mode simulation.