Studies on preparation of ultrafiltration titania membrane by reversed micelle method

Reversed micelle method was used to prepare titania ultrafiltration membranes. Firstly, three reversed micelle of different sizes of titania particles were prepared by using tetrabutyl titanate, water and cyclohexane, and Span-80 as a surfactant, iso-pentanol as an accessory surfactant. TEM photographs show that the size of titania reversed micelle increases with the increase of [H₂O]/[Span-80] from 13.9 to 55.5 and decreases with [H₂O]/[Span-80] from 55.5 to 110.9. Pore size distributions of unsupported titania membranes agree with the TEM photographs, and show that the unsupported membrane prepared from the micelle with [H₂O]/[Span-80] of 110.9 has an average pore size of about 4.5 nm and its pore size distribution is the narrowest. Thus the micelle with [H₂O]/[Span-80] of 110.9 was used to prepare supported titania membrane. The titania membrane prepared has a most proper pore size of 16 nm by liquid-liquid displacement method and its pure water permeability is 1.57×10^-4 m³·(m²·s·MPa)^-1. The gas permeability of N₂ and H₂ are 4.3 mol·(m²·s·MPa)^-1 and 14.1 mol·(m²·s·MPa)^-1 respectively at normal temperature. The above results show that the titania membrane is defect-free.