Research On Modification Of Titanium Dioxide Photocatalytic Tail Gas Degradation Pavement Material

The increasing number of motor vehicles makes the pollution of the tail gas become an environmental problem that can not be ignored,and the photocatalytic properties of titanium dioxide make it possible to degrade automobile exhaust with pavement materials.Most of the existing researches use titanium dioxide to load on pavement materials,and the light response range of titanium dioxide is an important factor restricting its photocatalytic performance.Therefore,it is of great importance to modify the response range of titanium dioxide.It is also a new attempt to apply modified titanium dioxide to road surface.In this paper,nitrogen doped titanium dioxide was studied from three aspects: computational simulation,preparation characterization and pavement degradation performance test.First,CASTEP is used to calculate the band structure and the density of states of the substitutional and interstitial nitrogen doped titanium dioxide.The band structure is used to calculate the change of the band gap width before and after the nitrogen doping,and the influence of the electron orbit on the density of states is compared by the density of states calculation.The effect of nitrogen doping on the photocatalytic properties of titanium dioxide was investigated theoretically.Secondly,the preparation methods of nitrogen doped titanium dioxide are summarized,the common anatase titanium dioxide along with the modified titanium dioxide is prepared with the nitrogen doping rate in the CASTEP calculation.The prepared samples are characterized by XRD,FT-IR,XPS,TEM and UV-Vis DRS,which determines the crystal type,grain size and nitrogen doping mode of the samples.The result is compared with the calculation model of CASTEP.Thirdly,the advantages and disadvantages of the existing experimental device of photocatalytic tail gas degradation are summarized,and the improved experimental device suitable for this paper is developed and the tail gas concentration is calibrated to eliminate the system error.Finally,titanium dioxide and its nitrogen doped state were loaded on the pavement to carry out the experiment of photocatalytic tail gas degradation.The modified effect was verified by comparing the photocatalytic effect of titanium dioxide and its nitrogen doped state under the same design parameters,and the photocatalytic tail gas degradation of the modified titanium dioxide under different design parameters was compared.The optimum design parameters are determined,and the experiment is carried out on the different graded pavement under the optimum design parameters.The photocatalytic effect is compared and the construction quality acceptance of the different graded pavement after construction is carried out to verify the adaptability of the different grading road under the optimum design parameters.To sum up,in view of the modification of titanium dioxide photocatalytic tail gas degradation material,this paper predicts the properties of nitrogen doped titanium dioxide through the first principle,and uses this model as the guidance to prepare and characterize titanium dioxide and its nitrogen doped state.This paper also uses improved photocatalytic tail gas degradation system combined with fog sealing layer construction technique to obtain the optimal parameter of modified photocatalytic tail gas degradation pavement,and compares the adaptability of different graded pavement,and conducts the construction quality acceptance of the fog sealing layer combined with the standard in order to obtain the application range of the modified titanium dioxide photocatalytic tail gas degradation pavement.