Qu Qishu, Xuan Han, Zhang Kehua, Chen Xiaoming, Ding Yi, Feng Shaojie, Xu Qin
Key Laboratory of Functional Molecule Design and Interface Process, School of Materials and Chemical Engineering, Anhui Jianzhu University, Hefei 230601, China.
Key Laboratory of Functional Molecule Design and Interface Process, School of Materials and Chemical Engineering, Anhui Jianzhu University, Hefei 230601, China.
J Chromatogr A. 2017 Jul 7;1505:63-68. doi: 10.1016/j.chroma.2017.05.031. Epub 2017 May 15.
Metal-organic frameworks (MOFs) have been emerged as promising stationary phases for separations. However, the irregular shapes and wide size distribution of MOF particles have led to the high column backpressure and low column efficiency. We described here a kinetic controlling method to deposit zeolitic imidazolate framework (ZIF-8) onto the pore surface using core-shell silica spheres as support. By varying the volume ratio of N,N-dimethylformamide and methanol, the formation speed of ZIF-8 crystals were greatly suppressed, resulting in the growth of very thin layer (∼3.4nm) of ZIF-8 nanocrystals on the pore surface of the spheres instead of freedom growth of micron sized crystals in the solution. Thus prepared hybrid particles combined the merits of high selectivity of MOFs and the high separation performance of core-shell silica spheres. As a result, separation performance as high as 210000 plates/m for a mixture of xylene isomers was achieved.
金属有机框架材料（MOFs）已成为一种很有前景的分离固定相。然而，MOF颗粒形状不规则且尺寸分布较宽，导致柱背压高且柱效低。我们在此描述了一种动力学控制方法，以核壳二氧化硅球为载体，将沸石咪唑酯框架材料（ZIF-8）沉积在孔表面。通过改变N，N-二甲基甲酰胺和甲醇的体积比，ZIF-8晶体的形成速度得到极大抑制，从而在球的孔表面生长出非常薄的（约3.4纳米）ZIF-8纳米晶体层，而不是在溶液中自由生长微米级晶体。如此制备的杂化颗粒兼具MOFs的高选择性和核壳二氧化硅球的高分离性能。结果，对于二甲苯异构体混合物，实现了高达210000塔板/米的分离性能。
