Construction Of Three-dimensional Network Photocatalysic System And Removal Of Phthalate In Water

For a long time,the problem of separation and recovery of catalyst in powder suspension photocatalytic system has been restricting its further industrial application.Among them,the immobilization of catalyst is an effective means to solve this problem,but the catalyst after immobilization has the catalyst easy to fall off and the specific surface area.Small and practical problems such as poor mass transfer.Based on the above content,based on the TiO₂/Ti mesh of in-situ grown TiO₂ nanotubes,two three-dimensional network photocatalytic systems of stacked and Raschig rings were established.Under the illumination of UVA/Vis-LEDs,the three-dimensional network photocatalytic system can effectively degrade DMP,and the three-dimensional network photocatalyst can absorb the light radiation,transmit and reflect,and effectively improve the reaction system.Utilization of light energy and mass transfer efficiency.Firstly,the TiO₂/Ti mesh with good photocatalytic performance was prepared by anodization.The degradation rate of Rh B by UVA-LEDs for 90 min was 75.3%.By analyzing the current-time curve in the anodizing process,it is considered that the formation process of TiO₂ nanotubes includes three stages of formation of TiO₂ barrier layer,formation of TiO₂ porous film and formation of TiO₂ nanotubes.Based on the mesh structure of the titanium mesh itself,two three-dimensional network photocatalytic systems of stacked and Raschig rings were established.The results showed that for the stacked network photocatalytic system,the photocatalytic performance of the 5-layer TiO₂/Ti mesh was the best,and the reaction rate constant was 0.00871 min-1.For the Raschig ring-type photocatalytic system,the photocatalytic performance of the 7×7 mm Raschig rings was the best,and the reaction rate constant was 0.01115 min-1.In order to overcome the defects of low visible light utilization of TiO₂/Ti mesh,the effective degradation of DMP by three-dimensional network photocatalytic system under Vis-LEDs illumination was realized.N-TiO₂/Ti mesh was prepared by one-step anodization method under the illumination of in Vis-LEDs,the effects of stacking level,initial concentration,initial p H value and H2O2 on the degradation of DMP in stacked N-TiO₂/Ti network photocatalytic systems were investigated.The results showed that the photocatalytic effect of the 5-layer N-TiO₂/Ti mesh is the best.Compared with theN-TiO₂/Ti foil,the degradation rate of DMP by Vis-LEDs is increased by 25.7% for 120 min.Both acidic and alkaline conditions favor the degradation of DMP.Addition of H2O2 can significantly promote the degradation of DMP,but the H2O2 and Vis-LEDs alone can not effectively degrade DMP.In order to improve the photo-generated carrier separation efficiency of TiO₂/Ti mesh,the effective degradation of DMP in the three-dimensional network photocatalytic system under continuous flow operation was realized.The Ag-TiO₂/Ti mesh was prepared by photoreduction deposition method under the illumination of UVA-LEDs,the effects of hydraulic retention time,influent concentration and light intensity of Raschig ring-type Ag-TiO₂/Ti network photocatalytic system on the degradation of DMP under continuous flow operation were investigated.Raschig ring type Ag-TiO₂/Ti mesh having a random stacking property can receive optical radiation from different incident light angles.The influent concentration of Rasch ring-type Ag-TiO₂/Ti network photocatalytic system was in the range of 5?20 mg·L-1,and the hydraulic retention time is 30?90 min,and the efficient and stable degradation of DMP can be obtained.