A covalently integrated ZIF-8/polyamide acid mixed matrix membrane with superior gas separation performance

Zeolitic imidazolate framework-8 (ZIF-8) is a typical filler used to fabricate mixed matrix membranes (MMMs) on account of its attractive advantage of high selective permeability for gas separation. However, the performance is usually affected by filler aggregation due to strong interactions among fillers and weak interactions between the polymer and fillers, However, the performance is usually affected by filler aggregation due to strong interactions among fillers and weak interactions between the polymer and fillers, which will lead to a decrease of selectivity and the performance of gas separation will be strongly influenced. Herein, we modified ZIF-8 with 3-amino-1,2,4-triazole to obtain ZIF-8-NH 2 , Kapton polyamide acid was selected as the polymer matrix. Results showed that the ZIF-8-NH 2 /Kapton MMMs has a good compatibility interface between ZIF-8 and Kapton because of the covalent bridging, even the filler loading up to 45% (mass). The 45% (mass) of ZIF-8-NH 2 /Kapton membrane showed 297 barrer (1 barrer = 10 −10  cm 3 ·cm·cm −2 ·s –1 ·cmHg –1 , 1 cmHg = 1333.22 Pa, standard temperature and pressure) of the permeability of H 2 and 43.9 and 62.2 of selectivities for H 2 /N 2 and for H 2 /CH 4 , respectively, which are beyond the upper limit of Robeson 2008.