机械化学法合成小尺寸MOF填料助力高性能CO_(2)分离

Mechanochemically synthesized small sized MOF fillers assisted for highly efficient CO_(2) separation

利用金属-有机骨架UTSA-280具有特定刚性尺寸的一维孔道可以筛分CO_(2)、CH4、N2的特性,采用机械化学研磨法减小其颗粒尺寸,将UTSA-280掺入聚砜(PSf)中制备MOF基混合基质膜,用于天然气提纯和烟道气CO_(2)捕获。结果表明,在PSf中掺入UTSA-280不仅可以增加聚合物的CO_(2)渗透通量而且提高了气体分离选择性。当UTSA-280掺杂量为30%(质量)时,混合基质膜对CO_(2)/CH4、CO_(2)/N2的分离因子分别为56.39和53.17,CO_(2)的渗透通量为18.61 Barrer,相对于PSf纯膜,选择性分别提高了47.3%和63.5%,CO_(2)渗透通量提高了128.9%,打破了“trade-off”效应。该工作通过引进具有分子筛分效应的MOF填料,能够增加气体通量的同时提高混合基质膜对含CO_(2)气体的分离性能,对天然气的提纯以及烟道气的CO_(2)的捕获有重要意义。

UTSA-280 is a typical molecular sieving metal-organic framework(MOF)for separating CO_(2) from CH4 or N2,but the traditional solution-based synthesis method usually receives MOF particles with considerable size.Here an alternative mechanochemical way was used to fabricate small sized UTSA-280 particles,which was subsequently acted as filler materials in the polysulfone(PSf)based mixed matrix membranes(MMMs)for natural gas purification and CO_(2) capture in flue gases.It shows that the introduction of UTSA-280 filler in the PSf matrix not only accelerates the transmission of CO_(2) but also boosts the mixed gas separation factor of CO_(2)/CH4 and CO_(2)/N2.When the filler loading was 30%(mass)the CO_(2)/CH4 and CO_(2)/N2 separation factor were 56.39 and 53.17,respectively,and the CO_(2) permeability was 18.61 Barrer,compared with pure membrane,the CO_(2)/CH4 and CO_(2)/N2 separation factor and CO_(2) permeability showed 47.3%,63.5%and 128.9%enhancement ratio,respectively,thus breaking the"trade-off"limitation.By introducing this specific MOF with molecular sieving character,the MOF based MMMs can improve the permeability of CO_(2) as well as gas separation performance,which is of great significance to the purification of natural gas and the capture of CO_(2) in flue gas.