Studies On Treating Coking Water By Photocatalytic Oxidation Of Nanometer Sized TiO₂ Thin Film And Ti-MCM-41 Powder

Photo catalytic technology is a newly developed water treatment in recent years.It has attracted great attention because it can mineralize organic wastewater under normal conditions.By the process of catalysis,the organics can be decomposed to CO₂ and H₂O.Photocatalytic technology is considered as one of the most promising water treatments because is has no secondary pollution and fairly good effect on degradation.In recent two decades this method has made a great development.Coking wastewater is a kind of metallurgical wastewater with complex components and high concentration of organic and inorganic contaminants which are hard to be decomposed.So it is very essential to find an effective and financial way to treat the coking wastewater,and the photo catalytic treatment is efficient to reach the demand.In this dissertation,two kind of photo-catalysts were prepared.One of them is nanosized TiO₂ thin film immobilized on glass by sol-gel and coherence method.The substrate of film was characterized by XRD,UV-Vis,SEM and other analytic methods.The TiO₂ crystal is anatase with good catalytic activity. The other kind of photo-catalysts is Ti-MCM-41 powder immobilized on MCM-41 mesoporous molecular sieves using hydrothermal crystallization.The powder was characterized by XRD and FT-IR,it also has good catalytic activity.The phenol degradation was tested.The photo-catalytic effect was influenced by pH,reaction time,aeration quantity,oxidant quantity and catalyst quantity.The most optimized condition is:5 hours' irradiating by 3×30W ultraviolet lamp,pH:2.8,aeration quantity:2.5L/h,the H₂O₂ quantity:2.5ml/L, the Ti-MCM-41 quantity:0.5g/L.In the following experiments of treating coking wastewater,the GC/MC method was used to analyze the main composition of organic contaminants in the wastewater.About 69.30%of these organic contaminants are phenolic compounds.The results of GC/MS showed that using titanium as photo catalyst to degrade the COD and phenolic compounds in the coking wastewater is very effective.