(231c) High-Flux Thin Film Nanocomposite Reverse Osmosis Membranes Prepared by Containing Functionalized Multi-Walled Carbon Nanotubes (MWNTs)

The pristine multi-walled carbon nanotubes (MWNTs) were firstly treated by mixed acid (H2SO4/HNO3=3/1 by volume) to yield acidified MWNTs with -COOH and -OH groups, and then MWNTs-polyamide reverse osmosis nanocomposite membranes were synthesized with m-phenylenediamine (MPD) and trimesoyl chloride (TMC) by interfacial polymerization of functionalized MWNTs dispersed in polyamide thin films. The surface morphology and structure of membrane were characterized using Fourier transform infrared spectrometry (FTIR), scanning electronic microscopy (SEM), transmission electron microscopy (TEM) and contact angle. The results showed that modified MWNTs yielded some hydrophilic groups, such as -COOH and -OH, which made acidified MWNTs as an additive of high water transport, hydrophilicity and better dispersion in solution; the functionalized MWNTs in the polyamide film had a dispersive morphology, and crossed in the polyamide layer, played as the role of water channel. Compared with the pure polyamide membrane, the MWNT-polyamide thin film nanocomposite reverse osmosis membranes had more hydrophilic surface, and the water flux of MWNT-polyamide membranes dramatically improved, the water flux of thin film nanocomposite membrane with 0.1% (m/v) acidified MWNTs was almost 2.8 times that of pure polyamide membrane. These MWNTs-polyamide reverse osmosis nanocomposite membranes with excellent performance would be of great potential in desalination and separating organics from aqueous solution.