Tuning the Adsorption Selectivity of ZIF‐8 by Amorphization

Abstract

Figure 3. a) Photograph and b) SEM imageo fthe self-standing a m ZIF-8 membrane. c) Single gas permeability and d) the corresponding ideal selectivities of a m ZIF-8membrane measured by time-lagpermeationt echnique.

Gas Adsorption Enhancement in Partially Amorphized Metal–Organic Frameworks

“…Also, experimental validation is encouraged, though in our results, the enhancement in porosity was observed for the low level of amorphization. Nevertheless, the degree of amorphization can be tuned by controlling the time of ball-milling , or by adjusting the compression pressure …”

“…Zhou et al 5 produced a zeolitic imidazolate framework (ZIF) glass with permanent porosity, but it still displayed a smaller surface area compared to the pristine crystalline structure. Also, a recent experimental study by Ma et al 6 showed that the mechanically amorphized ZIF-8 has less capacity for gas uptake than the parent structure; however, the amorphous structure displayed huge improvement in terms of selectivity. Purewal et al 7 revealed that the amorphized MOF-5 exhibits higher volumetric uptake for hydrogen than the parent structure.…”

“…Nevertheless, the degree of amorphization can be tuned by controlling the time of ball-milling 19,50 or by adjusting the compression pressure. 6 Finally, the process in which we identify these deformed MOFs can be crucial when it comes to evaluating which MOFs can maintain (or even increment) gas storage performances during long-term usage when inevitably, the materials might incur deformations/defects. As we have presented here, because of the enhancement in the surface area, the partially amorphized structure can outperform the perfect crystalline for gas uptake (Figure 7a,b).…”

Gas adsorption in the topologically disordered Fe-BTC framework

“…25 Recently, mechanical amorphisation of ZIF-8 [Zn(mIm) 2 ; mIm -2-methylimidazolate], to form a m ZIF-8 (a m denoting amorphisation by ball milling), was found to enhance the adsorption selectivity of C 3 H 6 over C 3 H 8 . 26,27 Despite this, investigations into disordered MOFs for applications in gas storage and separation are of comparatively low prevalence with respect to their crystalline counterparts, particularly in the area of C 3 H 6 /C 3 H 8 separation.…”

Gas Adsorption Selectivity in Topologically Disordered Metal–Organic Frameworks

“…25 Recently, mechanical amorphisation of ZIF-8 [Zn(mIm)2; mIm -2-methylimidazolate], to form amZIF-8 (am denoting amorphisation by ball milling), was found to enhance the adsorption selectivity of C3H6 over C3H8. 26,27 Despite this, investigations into disordered MOFs for applications in gas storage and separation are of comparatively low prevalence with respect to their crystalline counterparts, particularly in the area of C3H6/C3H8 separation.…”