Abstract: For the modification of α-Al₂O₃ microfiltration membrane, the nano-crystalline TiO₂ coating was obtained by a homogeneous precipitation method using titanium sulfate and urea as raw materials. The effects of reaction temperature, reactant concentration and coating times on the modification of the membrane were investigated systematically. The micro-structure of nano-crystalline TiO₂ coating and its modifying mechanism were also studied by means of TEM, Zeta electric potential analyzer etc. The results show that nano-crystalline TiO₂ modifying coating composed of 10～15nm grains is smooth and dense, and the water flux of the modified membrane is increased by more than 19% over the membrane before modification.

Key words: homogeneous precipitation method, microfiltration membrane, titanium oxide, modifying coating