High-Performance Polyamide Thin-Film Nanocomposite Membranes Containing ZIF-8/CNT Hybrid Nanofillers for Reverse Osmosis Desalination

Thin-film nanocomposite (TFN) membranes incorporating nanofillers in ultrathin and selective polyamide layers have improved desalination performance in conventional reverse osmosis (RO) membranes. However, further enhancement of RO performance in TFN membranes using only a single nanofiller remains challenging due to difficulties in optimizing permselectivity, dispersibility, and chemical stability. To circumvent this limitation, we prepared hybrids of zeolitic imidazole framework-8 (ZIF-8) and carbon nanotubes (CNTs) to exploit the advantages of both filler phases for the development of high-performance TFN RO membranes. The synthesized ZIF-8/CNT hybrids showed continuous and well-distributed ZIF-8 nanocrystals grown on one-dimensional CNT templates. TFN membranes containing ZIF-8/CNT hybrids outperformed those prepared with a single phase both in RO performance and chlorine stability, attributed to a high aspect ratio and microporosity and the radical scavenging effect of oxygen functional groups in CNT templates. The results demonstrate that MOF/carbon hybrid nanofillers can contribute to the rational design of advanced TFN membranes for RO desalination.