Diffusive separation of propylene/propane with ZIF-8 membranes

Effect of Temperature on Synthesis of ZIF-8 Membranes for Propylene/propane Separation by Counter Diffusion Method

“…In the case of M4 and M5, no ZIF-8 particles were observed on the inner surface, and the substrate remained exposed as shown in Fig. 4(b), which is also similar to our previous observations 21), 24) . The characteristic properties of the ZIF-8 membranes, such as the loading capacities, intensity ratio, and outer-and inner-surface structures can be explained in combination with the cross-sectional SEM-EDX analyses, as shown in Fig.…”

“…Kwon and Jeong also reported the preparation and permeation properties of ZIF-8 membranes using the counter diffusion method, where a selectivity of up to 55 was achieved for an equimolar mixture of propylene/propane 19) . We have recently reported the preparation of ZIF-8 membranes with a propylene/propane ideal separation factor of 59, for which the ZIF-8 layer was prepared within the pores of an α-alumina porous substrate using the counter diffusion method 21) , subsequent to the development of the HKUST-1 membrane using the counter diffusion method 23) . Brown et al recently reported the scalable preparation of ZIF-8 membranes, where the ZIF-8 layer was formed on the inner surface of polymeric hollow fibers using interfacial microfluidic membrane processing (IMMP) based on the counter diffusion concept 20) , giving rise to a propylene/propane selectivity as high as 12.…”

“…We recently reduced the thickness of ZIF-8 membranes by increasing the zinc nitrate concentration in the inner part of the capillary substrate, which was derived from the enhanced reaction rate due to the higher solution concentration 24) . Furthermore, we reported the effect of the solution interface by using an immiscible solution pair, as well as the effect of the solution concentration on the structure and permeation properties of ZIF-8 membranes 25), 26) . In addition to the preparation conditions, the reaction temperature is also expected to exert a significant influence on the rate of reaction and diffusion in the counter diffusion method; however, this effect has not yet been reported.…”

“…ZIF-8 membranes are conventionally prepared by the in-situ growth method 6) 10) , secondary growth method 11) 18) , and the counter diffusion method 19) 21) . Pan et al first reported the effective separation of propylene/propane with ZIF-8 membranes using the secondary growth method, achieving a selectivity of up to 50 for an equimolar mixture of propylene/propane 22) .…”

Mathematical Modeling and Simulation of Propylene Absorption Using Membrane Contactors

“…Extensive research has been done on various kinds of membranes including carbon molecular sieves [8], polymers [9], zeolites [10], and facilitated transport membranes [11]. Polymeric and polymeric-composite membranes are one of the major interesting media which are studied in propylene separation from an olefin-paraffin mixture.…”