Continuous Separation of Light Olefin/Paraffin Mixtures on ZIF-4 by Pressure Swing Adsorption and Membrane Permeation

Abstract

In this study, two zeolitic imidazolate frameworks (ZIFs) called ZIF-4 and ZIF-zni (zni is the network topology) were characterized by sorption studies regarding their paraffin/olefin separation potential. In particular, equilibrated pure and mixed gas adsorption isotherms of ethane and ethene were recorded at 293 K up to 3 MPa. ZIF-4 exhibits selectivities for ethane in the range of 1.5–3, which is promising for continuous pressure swing adsorption (PSA). ZIF-4 shows high cycle stability with promising separation potential regarding ethane, which results in purification of the more industrial desired olefin. Furthermore, both ZIF materials were implemented in Matrimid to prepare a mixed matrix membrane (MMM) and were used in the continuous separation of a propane/propene mixture. The separation performance of the neat polymer is drastically increased after embedding porous ZIF-4 crystals in the Matrimid matrix, especially at higher feed pressures (3–5 barg). Due to the smaller kinetic diameter of the olefin, the permeability is higher compared to the paraffin.

In situ Raman and FTIR spectroscopic study on the formation of the isomers MIL-68(Al) and MIL-53(Al)

“…Metal-organic frameworks (MOFs) have been the subject of intense research interest in the past two decades. 1 Their extremely high surface areas, highly-organized micropore networks, wide range of geometries, dynamic framework effects and ease of functionalization make them promising candidates for a variety of applications in the elds of gas adsorption, separation 2,3 and storage, 4,5 catalysis, 6,7 luminescence, 8 drug delivery 9,10 and sensing. 11 However, the underlying formation mechanism and effect of synthesis conditions on the resulting MOF structures are oen not well understood.…”

Alternatives to Cryogenic Distillation: Advanced Porous Materials in Adsorptive Light Olefin/Paraffin Separations

“…Hartmann et al reported that ZIF‐4 (ZIF = zeolitic imidazole framework) preferentially adsorbs paraffins over olefins with the same carbon numbers as verified by breakthrough experiments . In a subsequent study, Hovestadt et al examined the C 2 H 4 /C 2 H 6 separation performance in a commercial PSA setup loaded with ZIF‐4 powder . The adsorption‐desorption cyclic experiments of two parallel adsorption columns show that the setup can produce C 2 H 4 streams with purity up to 99.16% over 36.5 cycles and 50 h, indicating the great potential of paraffin‐selective adsorbents like ZIF‐4 in practical C 2 H 4 purification.…”

Fast, Simple and Sensitive Determination of Coumaric Acid in Fruit Juice Samples by Magnetite Nanoparticles‐zeolitic Imidazolate Framework Material

“…ZIF-4 was prepared as described literature with a slightly modifications [34]. 0.585 g of zinc nitrate hexahydrate and 9.41 g imidazole were dissolved in 5 mL and 40 mL ultrapure water separately.…”