Interfacial synthesis ZIF-8@HPAN membrane for highly efficient humic acid removal

In this study, a ZIF-8 thin layer deposited on the surface of a hydrolyzed polyacrylonitrile (HPAN) membrane was used for highly efficient humic acid removal. The thin ZIF-8 layer was synthesized by using a two-step interfacial synthesis method, based on liquid–liquid interfacial coordination polymerization. The formation of a continuous ZIF-8 layers was confirmed by X-ray diffraction, Fourier-transform infrared spectroscopy, scanning electron microscopy, and atomic force microscopy. The effects of the synthesis conditions including reaction time, precursor concentration, and other operating conditions on the ZIF-8 composite membrane performance were studied using humic acid solution as organic waste. The results showed when the reaction time was extended, or when the precursor concentration was increased, the ZIF-8 layer deposited on the membrane surface became denser. Compared with the unmodified HPAN substrate, the composite membrane deposited with the ZIF-8 layer showed better processing ability for organic matters due to the strong electrostatic interaction of organic matter with the ZIF-8@HPAN membrane and the ZIF-8 particles unique structural characteristics, which shows a great application prospect for humic acid treatment compared with other membrane technologies.