Aggregation suppressed thin film nanocomposite (TFN) membranes prepared with an in situ generation of TiO2 nanoadditives

Abstract

We report a promising strategy for the preparation of nano-aggregation suppressed thin film nanocomposite (TFN) membranes via an in situ method. Tetra-butyl ortho-titanate (TBOT) was added to the organic phase to prepare the new TFN membranes (in situ TFN). The in situ addition of TBOT produced TiO₂ nanoparticles in the polyamide layer during interfacial polymerization. In comparison with TFN membranes fabricated by the conventional method (ex situ TFN preparation), the nanoparticles in the in situ synthesized TFN membranes exhibited better dispersion, and more TiO₂ nanoparticles were observed on the membrane surface. Surprisingly, at a rather low concentration of TBOT (250 mg L⁻¹), the water flux of the in situ TFN membranes was increased by more than 50% in comparison with that of a pure polyamide membrane with negligible rejection loss, which was close to the performance of the sate-of-the art TFN membranes. The surface properties of the membranes were investigated by scanning electron microscopy (SEM), X-ray diffraction (XRD) analysis, X-ray photoelectron spectroscopy (XPS), and contact angle analysis. Our results demonstrate that in situ generation of nano-additives can effectively suppress nano-agglomeration and improve the performance and surface features of TFN membranes.