Abstract：Composite photocatalyst was prepared with nano TiO2 loaded mesoporous ZSM-5molecular sieve, its morphology and composition were characterized with scanning electron microscope (SEM), specific surface and pore size analyzer and X-ray diffraction, and treatment effects of TiO2/ZSM-5/persulfate system on the advanced degradation of residual organic pollutants (ROPs) from coking biological treated wastewater and mechanisms therein were investigated with batch experiments. The results show that an average COD effluent concentration of 76.3mg/L and percent COD removal of 78.2% can be reached under the initial average COD concentration of 352mg/L, catalyst dosage of 1.6g/L, pH of 3.0, C(Na2S2O8) of 0.8g/L and 180min of reaction at room temperature, which meets existing pollutants discharge standards. The ROPs photocatalysis process can be described with the Langmuir-Hinshelwood model, which indicats that S2O82- captured the electronics easily on the catalyst surface with the micro meso porous structure, reduced the recombination rate of hole and electron, promoted the formation of ·OH and SO4-· and strengthened the ROPs adsorption and photocatalytic degradation significantly. The contaminants before and after the treatment were measured by the determination of degradation and transformation rules with GC-MS, which revealed that the benzenes characteristic pollutants can be degraded efficiently, but the intermediate products increased remarkably.
