Abstract: TiO₂/SiO₂ composite film made by liquid deposition on the surface of coal fuse sintered filter material was used to study its photocatalytic degradation effect for DNNP waste water from a Huannan chemical plant.The test result achieved a decoloration rate and COD_Cr decrease of 75.54% and 61.51% respectively at one hour degradation with TiO₂/SiO₂ composite film with also lighting and aeration, where the waste water (COD_Cr, 318 mg/L and chroma, 3 750 times) was first diluted by 20 times to gain an initial pH of 3, into which oxydol was added at a dosage that was 0.9% of the waste water volume.The result was ideal.

Key words: TiO₂/SiO₂ composite film, DNNP waste water, Photocatalytic degradation