用于CO2/N2分离的氧化石墨烯量子点混合基质膜的制备及性能研究

将氧化石墨烯量子点(GOQDs)引入聚醚嵌段共聚酰胺(PEBA),通过溶剂挥发法制备了具有良好分散性能和界面结合性能的PEBA/GOQDs混合基质膜,研究了GOQDs添加量对混合基质膜理化性质及气体渗透性能的影响。结果表明:GOQDs可均匀分散在PEBA聚合物基质中,提高了混合基质膜的力学性能;GOQDs含有大量的羟基和羧基,亲和能力强,对CO2有强吸附作用,显著提高了混合基质膜的CO2/N2渗透性能。当GOQDs添加量为3%(质量分数)时,PEBA/GOQDs混合基质膜的CO2渗透系数为184.32Barrer,CO2/N2选择性达到了63.56,与纯PEBA膜相比分别提高了241%和253%。

模板法多孔炭的制备及CH_4/N_2/CO_2吸附分离

以糠醇为碳源,模板法两次浸渍制备多孔炭,采用XRD、SEM、FTIR、N_2吸附-脱附等方法对其进行表征,利用磁悬浮天平测量了CH_4,N_2,CO_2的吸附等温线,并对吸附等温数据进行Langmuir拟合,由Henry常数预测多孔炭对混合体系的平衡选择性。表征结果显示,多孔炭孔分布较窄,具有丰富的孔结构,在一定程度上复制了分子筛的孔道结构,且表面呈现一定的极性,有利于CH_4,N_2,CO_2的吸附和分离。实验结果表明,CH_4,N_2,CO_2的平衡吸附量大小的顺序为:CO_2>CH_4>N_2,Langmuir模型拟合相关系数均大于0.993,拟合效果较好,可用Langmuir理论解释气体在多孔炭孔结构及表面的吸附行为,制备的多孔炭适用于烟道气中CO_2的吸附与分离及煤层气等非常规天然气的提纯,但对垃圾填埋气的分离效果不显著。

以3-甲氧基苄胺改性聚乙烯基胺制备CO_2分离膜

为提高CO_2分离膜高压下的渗透选择性能,利用含苯环小分子胺3-甲氧基苄胺与聚乙烯基胺(PVAm)制备了PVAm-3-甲氧基苄胺涂膜液,并将其涂敷到聚砜(PSf)超滤膜上制备了PVAm-3-甲氧基苄胺/PSf固定载体复合膜.PVAm-3-甲氧基苄胺/PSf膜的红外谱图结果显示,3-甲氧基苄胺的伯胺基能与PVAm的伯胺基或酰胺基形成氢键交联网络.利用模拟烟道气组成的CO_2/N2混合气(体积比20/80),考察了PVAm-3-甲氧基苄胺/PSf膜和PVAm/PSf膜的渗透选择性能.结果表明,PVAm-3-甲氧基苄胺/PSf膜的CO_2渗透选择性能得到了大幅度提高,高压下更为显著.

A Research Note on the Adsorption of CO2 and N2

Experiments were made for the adsorption of CO2 and N2 on typical adsorbents to investigate the effects of porous structure and surface affinity of adsorbents as well as those of adsorption temperature and pressure that might cause the variation of adsorption mechanism. It is shown that polar surface tends to enlarge the adsorption difference between CO2 and N2, and the difference is more sensitive to temperature than the adsorbents with non-polar surface. The adsorbents with non-polar surface are not much sensitive to the effect of water vapor, though the water vapor interferes the separation remarkably. The separation coefficient linearly increases with the micro- pore volume per unit surface area of activated carbons, but no rule is shown on mesoporous silicon materials. The function of adsorption mechanism on the separation is not as much as expected.