Enhancement of pozzolanic clay ceramic membrane properties by niobium pentoxide and titanium dioxide addition: Characterization and application in oil-in-water emulsion microfiltration

Abstract

Pozzolanic clay was mixed with niobium pentoxide (Nb2O5) and titanium dioxide (TiO2) to improve the filtering properties of disk-type ceramic membranes, in 0.1 g L−1 oil-in-water emulsion. The effect of sintering temperatures of 1000 °C, 1100 °C and 1150 °C was evaluated. The newly formed hydrophilic membranes were fully characterized in terms of porosity, mechanical strength, X-ray fluorescence (XRF), X-ray diffraction (XRD), thermogravimetric analysis (TGA), water contact angle, scanning electron microscopy (SEM), atomic force microscopy (AFM), and hydraulic permeability. The applicability of the developed membranes was evaluated using crossflow microfiltration (MF) of an oil-in-water emulsion. The results demonstrated that the membranes could offer higher permeate fluxes with low permeate TOC contents that were compliant with that reported in the literature. The niobium pentoxide increased the hydraulic permeability and initial permeate flux by up to 118% and 72%, respectively, compared with the pure clay membranes. The pore blocking models were adjusted to the MF data of the membranes sintered at 1100 °C, revealing that the intermediate pore blocking was the major fouling mechanism for pure clay and niobium pentoxide enriched membranes, while complete pore blocking was best fitted to the titanium dioxide containing membrane. Overall, the results demonstrated that the mixing of pozzolanic clay and niobium pentoxide has great potential.