Fabrication and characterization of polyamide thin film nanocomposite (TFN) nanofiltration membrane impregnated with TiO2 nanoparticles

Abstract

A novel thin-film nanocomposite (TFN) nanofiltration membrane has been developed via interfacial incorporation of aminosilanized TiO2 nanoparticles. Polyethersulfone (PES) barrier coating on a porous a-Al2O3 ceramic hollow fibre membrane was employed as the substrate layer. TiO2 nanoparticles were incorporated in pure and functionalized forms into trimesoyl chloride (TMC) organic phase and m-phenylenediamine (m-PDA) aqueous phase, respectively. The surface functionalization of TiO2 nanoparticle was confirmed by XRD, FTIR and UV-vis reflectancespectral analysis. Surface properties of the fabricated composite membranes were investigated using SEM, EDX, AFM and contact angle goniometry. Heat resistibility of polyamide layers were examined using thermogravimetric analysis (TGA). Membranes intrinsic properties such as: the permeability, selectivity and pore size determination were also elucidated. The silane coupling agent containing amino-functional groups reinforced TiO2 nano fillers for the good dispersion inside the polyamide skin layer by reducing their surface energy. At ultra-low concentration (0.005 wt.%), the functionalized TiO2 nanoparticles improved the salt rejection to 54% as well as water flux to 12.3 l/m2 h. By incorporating a higher concentration of TiO2 nanoparticles, water flux was increased up to 2-fold compared with the pure polyamide membrane with negligible rejection loss. These results demonstrated competency of using functionalized inorganic nanoparticles to increase the product flux and the separation efficiency.