| Ink wastewater,as a kind of complex,hardly to biodegradation and large amount of emissions with the improvment of the printing technology,it is a hot research that develop a economical and efficient treatment of wastewater.Photocatalytic oxidation is a popular friendly water treatment technology in recent years that can be used to treat printing wastewater.TiO2 as a friengdly catalysis have many fascinating properties,including non-toxic,inexpensive,excellent photocatalytic.SiO2 aerogels also have fascinating properties,such as high surface aera,high porosity and outstanding support material of catalysis.In this paper,SiO2/TiO2 composite aerogels were prepared by sol-gel and ambient pressure drying.The SiO2/TiO2 composite aerogels not only present the photocatalysis of TiO2,but also overcome problems that TiO2 powder difficult to separate and recover and high cost.As a composite photocatalyst to deal with offset ink wastewater,the results found that the photocatalyst can significantly reduce the COD and chroma of wastewater.The major researchs are as followings:?1?Preparation of SiO2/ TiO2 composite aerogelsSiO2/ TiO2 composite aerogels were prepared by using TEOS and TBT as raw materials,tetreaosysilane and trimethylchlorosilane as surface modifiers,and N-hexane as a low surface tension solvent.And the suitable parameters as following:n?TBT?:n?TEOS?:n?EtOH?:n?HAC?:n?H2O?:n?H+?:n?DMF?=1:1:20:2:6:1×10-3:0.2.The results showed that aerogels have excellent thermal stability,porous and Si and Ti were distributed uniformly.The effects of different ratios between Si and Ti on the density,specific surface area and structure of SiO2/TiO2 composite aerogels were studied in details,It is demonstrated that density decreased with increasing Si content,the density was at least 0.17g/cm3.When n?Si?:n?Ti?=1:1,the specific surface has a maximum of 701.6m2/g.The effect of calcination temperature on the specific surface area and crystal structure ofSiO2/TiO2 composite aerogels was also discussed.It is showed that the specific surface area reduced after calcination.And when at 800?,the aerogels still had a large specific surface area of 220.68m2/g.At the same time,The XRD patterns showed crystallinity enhancement at 800?.?2?Study on the application of SiO2/TiO2 composite aerogelsIn this paper,the influence factors of photocatalytic oxidation of offset ink wastewater were explored,and the optimum process of photocatalytic oxidation was obtained.It was treated by coagulation method to reduce the turbidity of the offset printing ink wastewater.Then the offset printing ink wastewater was degraded by Photocatalytic oxidation.Research shows that COD and chroma removal rate of the offset ink wastewater reached 92.4% and 94.6% respectively when the wastewater was treated under the following conditions:dosage of catalyst?Which is gotten at 800 ? and n?Si?:n?Ti?=1:1?0.4g/L,light radiation time 30 min and pH value 5.Its catalytic effect was significantly better than P25.The reusing result showed that the removal rate was still more than 85%after 8 experiments.Its reuse was significantly better than P25.The method of photocatalytic oxidation treatment of offset ink wastewater is feasible,and provides a basis for the industrial treatment of printing ink wastewater. |
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