Synthesis,Characterization and Photocatalytic Degradation for Coking Wastewater of Fe_3O_4 Nanoparticles/Bentonite

Al-pillared clays supported Fe_3O_4 nanoparticles were prepared as composite catalyst.XRD,BET and SEM were used to study its microstructure,surface area and average particle size.The supported Fe_3O_4 nanoparticles with a size about 20～30 nm existed on the surface of clays,with better dispersing and no obvious aggregation than that without bentonite support.The obtained catalyst was applied for advanced treatment of sedimentation tank effluent of coking process under UV. Results indicated that COD and chroma of the wastewater could be reduced from 140 mg/L and 400 to 54.44 mg/L and 10 respectively in the conditions as catalyst dosage 0.7 g/L,initial pH 2.5,temperature 40 t and initial H_2O_2 concentration 17.6 mmol/L,which could satisfy the recycled water standard of GB/T 19923-2005 with COD less than 60 mg/L and chroma less than 30.The removal rates of COD and chroma in 4 cycles remained stable.