Novel antifouling and photocatalytic immobilized iron-doped cerium oxide@halloysite nanotubes decorated polyethersulfone membranes

Abstract

Novel polyethersulfone (PES) ultrafiltration (UF) membranes were prepared by incorporating different contents of iron-doped cerium oxide-halloysite nanotubes (FC@NHT) nanocomposites onto the PES membranes. The properties of the prepared nanocomposite membranes were investigated using Attenuated Total Reflectance-Fourier Transform Infrared spectroscopy (ATR-FTIR), X-ray diffraction (XRD), thermo-gravimetric analyzer (TGA) and scanning electron microscope (SEM). The results showed that iron dopped cerium oxide (FC) was indeed successfully loaded on the surface of halloysite nanotubes (HNTs). SEM characterization of FC@HNT/PES membranes showed an increase in pore sizes and microvoids which resulted in an increase in both hydrophilicity and flux due to the impact of FC@HNT. Pure water flux of 2% FC@HNT/PES (M4) was increased from 55.9 L.m⁻².h⁻¹ (0% FC@HNT/PES) to 320.4 L.m⁻².h⁻¹. The membranes also showed high antifouling properties towards humic acid (HA). This was attributed to the membranes becoming more hydrophilic upon modification. Subsequently, this reduced membrane-foulant hydrophobic interactions and made it difficult for hydrophobic contaminants to be attached onto the membranes surface. Photocatalytic ability of the modified membranes was tested against imidacloprid (IMD) insecticides. The membrane (M4) showed high photocatalytic activity of about 79% in 120 mins and 85.7% in 180 mins. The immobilization of FC onto the surface of the HNTs was for the homogenous dispersion of the nanoparticles and to mitigate the issue of agglomeration. Other remarkable functionalities are also provided by this integration. The membrane’s ability to function as system for water filtration and for the degradation of imidacloprid pesticide with high antifouling propensity is by far its most intriguing aspect of this work.