SiO2-ZrO2 nanofiltration membranes of different Si/Zr molar ratios: Stability in hot water and acid/alkaline solutions

SiO2-ZrO2 nanofiltration membranes were fabricated by coating different molar ratios of SiO2, SiO2-ZrO2 (9/1, 7/3, 5/5, 3/7), and ZrO2 sols onto α-alumina porous tubes and firing at 200 and 550 °C. The SiO2 and SiO2-ZrO2 (9/1, 7/3, 5/5) membranes fired at 200 and 550 °C showed pore diameters ranging from 0.65 to 0.80 nm, while SiO2-ZrO2 (3/7) and ZrO2 membranes fired at 550 °C showed larger pores than those fired at 200 °C due to the formation...