源自密胺基多孔聚合物的富氮微孔炭及选择性吸附CO2

摘要

以间苯二甲醛和三聚氰胺为原料,通过Schiff碱缩合反应合成了密胺基多孔聚合物(POP),经高温炭化后得到富氮微孔炭(NMC).利用N2吸脱附和傅里叶变换红外(FTIR)光谱表征了POP和炭化后产物NMC的结构和组成,与POP相比, NMC的官能团数量减少,比表面积和微孔孔容大幅增加.元素分析表明NMC含氮量高达12.5%(w).采用体积法测定了CO2、CH4和N2在NMC上的单组分吸附平衡等温线, NMC展示出良好的CO2吸附性能,298 K、100 kPa下CO2平衡吸附量可达2.34 mmol∙g-1.双位Langmuir (DSL)模型和单位Langmuir (SSL)模型分别较好地描述了CO2、CH4和N2在NMC上的吸附平衡数据,在此基础上,应用理想吸附溶液理论(IAST)预测了双组分混合气在NMC上的吸附等温线,结果表明NMC对CO2-N2和CO2-CH4有非常高的CO2吸附选择性,分别为144.9和12.8.%Nitrogen-rich microporous carbon (NMC) was prepared by the carbonization of a melamine-based porous polymer (POP), which was synthesized via a Schiff base condensation using isophthalaldehyde and melamine as starting materials. N2 adsorption-desorption and Fourier transform infrared (FTIR) spectroscopy were used to characterize the structural properties of POP and the derived NMC. NMC contains less functional groups and has a higher specific surface area and microporous volume compared to POP. NMC has a N content of up to 12.5%(w), as determined by elemental analysis. Single-component adsorption equilibrium isotherms of CO2, CH4, and N2 on NMC were obtained using a volumetric method. NMC has a good CO2 capture property and its CO2 adsorption capacity was 2.34 mmol∙g-1 at 298K and 100kPa. Dual-site Langmuir (DSL) or single-site Langmuir (SSL) models appropriately describe the adsorption equilibrium behavior of CO2, CH4, and N2 on NMC. Based on the combined fitting parameters, binary adsorption isotherms were predicted by ideal adsorbed solution theory (IAST). Very high adsorption selectivities of CO2 over N2 and CH4 were obtained and the values were 144.9 and 12.8, respectively.