To address the disadvantage of suspended phase TiO2 powder which is difficult to separate and recycle in the treatment of liquid pollutants and to further improve utilization of solar energy by TiO2

Pr3+:Y2SiO5 powder

TiO2 membrane and Pr3+:Y2SiO5/TiO2composite membranes were prepared via the sol-gel method. XRD and SEM were used to characterize the properties of the samples. The relationship between efficiency of photocatalytic degradation of methylene blue by Pr3+:Y2SiO5/TiO2 composite membrane and number of coating layers was investigated. Degradation rate could be as high as 96.43% with five coating layers of Pr3+:Y2SiO5/TiO2 composite membrane

and the second and third degradation rates were 82.46% and 74.94%

respectively. With increasing area of Pr3+:Y2SiO5/TiO2 composite membranes

degradation rate increased for a period of time then decreased finally. Degradation rate could be as high as 96.43% with eight coating layers of the membrane. Degradation rate would increase to 96.18% when illumination intensity reached 100 W. However

degradation rate decreased evidently with the increase of initial concentration of pollutions.