Preparation and characterization of polyvinyl butyral/zeolitic imidazolate framework‐8 nanocomposite ultrafiltration membranes to improve water flux

Abstract

AbstractAddition of porous nanoparticle zeolitic imidazolate framework‐8 (ZIF‐8) to the ultrafiltration membrane of polyvinyl butyral (PVB) improves membrane performance. In this research, first ZIF‐8 was synthesized, and its structure was investigated by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), and X‐ray diffraction (XRD) methods. The membrane was made by phase inversion process, and its morphology was investigated by SEM, atomic force microscopy (AFM), and water contact angle. The results of the SEM reveal that the amount of finger‐like structures and porosity in the nanocomposite membrane increased compared to the pure membrane. The water contact angle measurement showed that the membrane hydrophilicity is increased through addition of the ZIF‐8 nanoparticles. The increase in hydrophilicity leads to the increase in water flux and decrease in fouling. Surface roughness is reduced by addition of the ZIF‐8 nanoparticles, which causes attachment of bovine serum albumin (BSA) protein on the membrane surface more difficult. Therefore, fouling declined, and stability and durability of the membrane are increased. The results showed the increase in pure water flux and BSA rejection with increasing the ZIF‐8 loading up to 3 wt%, and then, it is slightly decreased by addition of 4 wt% ZIF‐8. The pure water flux reduction was due to the agglomeration of the nanoparticles at 4% content and blockage of pore membrane. The pure water flux of the ZIF‐8/PVB membrane at 3.0 wt% loading is increased to 107%, compared with the pure PVB membrane.