Preparation Of Perovskite-type Composite And Study On The Degradation Of The Solubilized PAHs Wastewater

Polycyclic aromatic hydrocarbons(PAHs)is a kind of refractory organic pollutants because of its strong carcinogenic,mutagenicity and low steam pressure,high octanol/water partition coefficient and poor bioavailability.Surfactants have solubilization effect on PAHs.The system of PAHs solubilization wastewater is complex and difficult to degrade,which is seriously dangerous to human health.Therefore,the effective treatment of PAHs solubilization wastewater is still an urgent problem to be solved.In this project,pahs sol-gel method was used to prepare La2Ti2O7/TiO2/CA,ZnTiO3/TiO2/CA,SrTiO3/TiO2/CA series composite photocatalysts by doping metal elements lanthanum,zinc,strontium modified TiO2 and using carbon aerogel(CA)as support.(1)FT-IR,XRD shows that the main forms of monomer crystal form in series composite La2Ti2O7/TiO2/CA are anatase type TiO2 and perovskite type La2Ti2O7;ZnTiO3/TiO2/CA,which are mainly perovskite type ZnTiO3 and rutile TiO2;SrTiO3/TiO2/CA contains perovskite SrTiO3,and TiO2 mainly exists in anatase structure.SrTiO3 shows that the three-dimensional network structure of CA substrate can give photocatalyst high loading and specific surface area,and both have bifunctional structure of enrichment and degradation of PAHs.CA part anchors surfactants directionally because of its hydrophobicity.The adsorption/desorption data of N2 adsorption/desorption data show that the composites belong to typical mesoporous materials.The heterojunction structure and perovskite compounds formed in the three composites reduce the recombination probability of photoelectron hole pairs,improve the photocatalytic activity of TiO2,and enhance the optical absorption properties of the composites under visible light radiation.(2)the composite showed the best adsorption effect on the solubilization system containing 5g/LTX-100100mg/L phenanthrene.(3)The series of La2Ti2O7/TiO2/CA,ZnTiO3/TiO2/CA,SrTiO3/TiO2/CA showed good visible light catalytic effect in the process of photocatalytic degradation.The adsorption process of TX-100 solubilized PAHs wastewater accords with Langmuir isotherm adsorption model and quasi-second-order kinetic model,which belongs to the spontaneous adsorption behavior ofΔG<0、△H>0、△S>0,and the photocatalytic degradation process accords with the quasi-first-order kinetic equation.When the molar doping contents of lanthanum,zinc and strontium are 0.50%,the degradation efficiency of the target pollutants is higher under the condition of visible light and ultraviolet light.The degradation rate of phenanthrene by 0.50%La2Ti2O7/TiO2/CA reached 93.3%under UV light,and the degradation efficiency of phenanthrene by composite 0.50%ZnTiO3/TiO2/CA was 96.7%,The degradation efficiency of phenanthrene by composite 0.50%SrTiO3/TiO2/CA was 89.3%.Under the condition of visible light,The degradation efficiency of phenanthrene by composite 0.50%SrTiO3/TiO2/CA、0.50%ZnTiO3/TiO2/CA and 0.50%La2Ti2O7/TiO2/CA is 77.3%、87.1%and 83.6%、。...