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 α-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 reflectance spectral 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 thermo-gravimetric 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 (0.005wt.%), the functionalized TiO2 nanoparticles improved the salt rejection to 54% as well as water flux to 12.3l/m2h. 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.