Polyamide thin-film nanofiltration membranes containing TiO2 nanoparticles

We report on novel polyamide (PA) nanocomposite membranes containing high loading of TiO2 nanoparticles synthesized via in-situ interfacial polymerization. Interfacial reaction occurred from the aqueous phase of m-phenyl diamine (MPD) and the organic phase of trimesoyl chloride (TMC) in which TiO2 nanoparticles were homogeneously dispersed. This new method provides higher loading (~5 w%) of TiO2 nanoparticles in the membranes and more robust structure of PA-TiO2 nanocomposite membranes. The in-situ polymerization and the incorporation of TiO2 nanoparticles were confirmed by field emission scanning electron microscope (FESEM), x-ray diffraction analyzer (XRD), x-ray photoelectron spectroscopy (XPS), and FT-IR spectroscopy. In addition, the effects of different preparation conditions such as curing temperature and curing time on membrane performance were investigated. The nanocomposite membrane, which was cured at 70EC for 5 min, exhibited the high and stable rejection value of more than 95% with respect to MgSO4 and the permeation flux of 9.1 L/m2h. Elemental analysis by XPS demonstrated that substantial amounts of TiO2 nanoparticles remained on the surface of the membranes after nanofiltration operation for 2 days.