Study on Ce‐Doped Nonstoichiometric Nanosilica for Promoting Properties of Polysulfone Membranes

Abstract

AbstractUsing the sol‐gel method a series of nonstoichiometric nanosilica doped with the rare earth element Ce (CexSi1–xO2–δ, x = 0.0–0.14) were prepared in order to modify the physicochemical properties of the nanosilica surface and to enhance the strength of the Ce‐nanosilica/polysulfone composite membranes. The CexSi1–xO2–δ samples were characterized by Fourier transform infrared spectra, X‐ray diffraction and X‐ray photoelectron spectra. The observations from these characterizations suggest that most Ce atoms enter the silica framework to form a Ce‐O‐Si solid solution while the cubic CeO2 phase is segregated when x >0.08. Transmission electron microscopy images show that CexSi1–xO2–δ particles are spherical with a uniform size distribution in the range of 30–50 nm and contain some inner pores with sizes up to a few nanometers. Specifically, Ce0.08Si0.92O2–δ‐700 calcined at 700 °C shows the biggest surface area, the smallest pore size and the highest hydrophilicity, which makes the Ce0.08Si0.92O2–δ/polysulfone composite membranes (8.0 wt %) exhibit the strongest mechanical strength (3.223 MPa), which is enhanced by more than 100% in comparison with the pure polymer membrane.