Co-MOF-74杂化膜的制备及其甲苯/正庚烷分离性能研究

摘要

以超支化聚合物Boltorn W3000为分离层材料,Co-MOF-74为促进传递粒子,1-甲基-2-吡咯烷酮(NMP)为溶剂,采用浸渍-热交联的方法制备Co-MOF-74/W3000杂化膜.Co-MOF-74中含有大量配位不饱和的金属位点和苯环,有助于提高膜对芳烃化合物的吸附选择性.利用粉末X射线衍射分析(PXRD)、热重分析(TGA)、电镜(SEM)和能量弥散X射线谱(EDS)对杂化膜的组成及膜的表面进行了表征,结果表明Co-MOF-74被成功添加到杂化膜中,并且Co-MOF-74的添加对膜的结构和形貌具有一定的影响.主要考察了Co-MOF-74的负载量对膜渗透汽化分离性能的影响.结果表明,掺杂Co-MOF-74可以提高W3000膜对甲苯/正庚烷混合物的分离性能.当Co-MOF-74的负载量(质量分数)为6％时,添加Co-MOF-74后的杂化膜Co-MOF-74/W3000-6.0具有最佳的分离性能:其通量为89g/(m2·h),分离因子为7.6,并且在30 h内可稳定运行.%Pervaporation membranes have been proved to have potential uses in the separation of aromatic/aliphatic mixtures.Herein,Co-MOF-74/W3000 hybrid membranes are designed and fabricated on the porous Al2O3 substrate for the recovery of toluene from its n-heptane co-mixture.The Co-MOF-74 contains rich open metal unsaturated sites and benzene rings,which not only enable them to be compatible well with the polymer but also could improve the adsorptive selectivity of the membrane towards toluene.Pervaporation results demonstrated that the incorporation of Co-MOF-74 indeed contributed to the significant improvements of these membranes for the separation performance.Particularly,the Co-MOF-74/W3000-6.0 membrane showed an optimal separation performance with the separation factor of 7.6 and the permeation flux of 89 g/(m2 · h) for the recovery of toluene from its mass fraction 50％ n-heptane mixture.Especially,the hybrid membrane could keep at a stable separation level after 30 h,which indicated that it has potential applications in industry.