Robust synthesis and performance of a titania-based ultrafiltration membrane with photocatalytic properties

Direct coupling of separation and photocatalytic degradation by using photocatalytic membrane is an
attractive way to solve problems like membrane fouling by adsorbed organic macromolecules or elimination of small organic molecules which cannot be efficiently stopped by a membrane.
A simple and robust synthesis route to a photocatalytically active titania membrane is here developed from a commercial titania hydrosol and commercial alumina supports. Reproducible defect-free layers with a thickness of about 3 m are prepared. The membrane performance in term of separation and photocatalytic activity are investigated. The pure water permeance is∼150Lh−1m−2bar−1 and the measured molecular weight cut-off is around∼50 kDa corresponding to an ultrafiltration membrane. The photocatalytic efficiency is tested by photo-oxidation under UV irradiation of a reference organic dye (methylene blue) for comparison with reference titania photocatalysts, and also with phenol as typical organic pollutant in water. The measured values of quantity of destroyed organic molecules per units of time and of membrane surface area are in the range 0.8–3.8×10−8mol sm−2