Polymer supported ZIF-8 membranes by conversion of sputtered zinc oxide layers

• Very thin (900 nm) ZIF-8 membranes were synthesized on polyacrylonitrile PAN support by a double-zinc-source method.
• Thin zinc oxide layer was deposited on PAN support by magnetron sputtering.
• Conversion of zinc oxide to ZIF-8 was proposed as a beneficial step during growth of ZIF-8 continuous layer.
• Prepared ZIF-8 membrane showed good performance for hydrogen-propane separation.

ZIF-8 composite membranes were synthesized at room temperature from aqueous solution by a double-zinc-source method on polyacrylonitrile (PAN) porous supports. The support was coated with zinc oxide (ZnO) by magnetron sputtering prior to ZIF-8 growth to improve the nucleation as well as the adhesion between the ZIF-8 layer and support. By this method, we were able to grow a continuous, dense, very thin (900 nm) and defect free ZIF-8 layer on a polymeric support. The developed ZIF-8 membranes had a gas permeance of 1.23 × 10−7 mol m−2 sec−1 Pa−1 for hydrogen and a selectivity of 26 for hydrogen/propane gases which is 5 times higher than the Knudsen selectivity. X-ray diffraction (XRD) and scanning electron microscopy (SEM) analysis were done to characterize the membranes.

Figure optionsDownload as PowerPoint slide