| Because the ocean is closely related to human life and plays a crucial role on the earth,it is urgent to solve the pollution of marine environment caused by human activities in recent years.Due to the high salinity and various pollutants in ocean,TiO2,as a kind of photocatalyst that can degrade pollutants stably and efficiently without selective photocatalysis,has great advantages and application prospects.But under the weak visible light conditions,the photocatalytic activity of TiO2 was unsatisfactory,which was caused by the limitation of its band gap width and quantum efficiency.Against the background,TiO2 photocatalyst P25,with stable application in industry,was taken as the carrier in this thesis.For the first step,solvothermal method was adopted to prepare metal and alcohol-reduced Ti3+self-doped photocatalyst for metal and alcohol reduction.Next,the composite photocatalyst was prepared by one-step solvothermal method and adsorption phase reaction technology respectively.And then,the application of the two composite photocatalysts in the treatment of three kinds of high-salinity industrial wastewater was explored.Finally,the catalyst was loaded into PP suspension ball after being loaded on polyurethane sponge,to prepare TiO2 photocatalytic suspension ball.During the process,various methods were applied for making characterization,including TEM,XPS,XRD and FT-IR,etc.According to the results,it can be obtained the following conclusions:（1）The surface of Ti3+self-doped photocatalyst prepared by thermal reduction of Zn,Al,Sn,ethanol,glycol and glycerin had disordered structure and amorphous layer structure.At the same time,Ti3+and oxygen holes were also formed.Among them,P25/Sn had the highest visible photocatalytic activity.（2）In the doping concentration range,the degradation rate of the catalyst La-P25/Sn decreased as the doping concentration increased.Both catalysts Yb-P25/Sn and Ce-P25/Sn had the best phenol degradation rate at doping concentration of 0.1%.After comparing the latter three rare earth metal elements,it can be concluded that Yb3+doping had the best effect on catalyst modification.（3）By applying the adsorption phase reaction technology,Au,Ag,Pt loaded on P25/Sn surface had quantum size.The SPR effect on the surface of metal and TiO2 caused the decrease of its band gap.In this way,its visible light response was enhanced and the utilization of solar energy was improved as well.Between 1%and 3%doping concentration range,the catalytic activity of the composite photocatalyst increased with the increase of the doping concentration.The composite photocatalyst3%Pt-P25/Sn had the best visible light catalytic performance with excellent recyclability.（4）3%Pt-P25/Sn was proved to be applicable for both agricultural high-salinity wastewater and dyeing high-salinity wastewater.In contrast,3%Ag-P25/Sn was more suitable for chemical high-salinity wastewater.When sulfuric acid pH was 4 and soaking time was 24h,catalyst powder was almost completely loaded on polyurethane sponge material.In addition,the degradation rate of phenol by the photocatalysis suspension could reach 87%with excellent reusability. |
