Preparation Of The Co²⁺/AgNbO₃ Composite TiO₂ Photocatalyst And Its Performance For Photocatalytic Degradation Of Toluene

Massive VOCs?Volatile Organic Compounds?was produced with the rap id development of the chemical engineering industry,causing serious air pollution in factory workspace and threatening workers'health.Lots of measures have been taken to deal with VOCs.Photocatalytic degradation technology was widely applied in VOCs treatment.Due to the poor catalytic activity and low efficiency of single photocatalytic materials,the research focus had been changed from single photocatalytic materials to composite photocatalytic materials in recent years.In this dissertation,Nb₂O₅ and AgNO₃ were applied by solid-state reaction method to prepare a kind of photocatalyst-materialsAgNbO₃;then?CoNO₃?₂·6H₂O was chosen to modify AgNbO₃.TiO₂ with a characteristic of porosity was prepared by the sol-gel method.The raw material was C₁₆H₃₆O₄Ti and the binder was?C₆H?NO?_n.Co²⁺/AgNbO₃ and porous TiO₂ were compounded in different preparation conditions to prepare the composite visible photocatalytic materials.The SEM analysis,IR active group determination and XRD crystal structure analysis were conducted to analyze the characteristic of the four materials including AgNbO₃,Co²⁺/AgNbO₃,porous TiO₂ and Co²⁺/AgNbO₃/porous TiO₂ composites materials.Then the effects on the removal efficiency of toluene gas in different dosages of the composite visible photocatalytic materials and initial concentrations of pollutants were studied.Experiments on the toluene gas degraded by the prepared units and composite materials were performed.Results indicated that when the photocatalyst dosage was0.028g/cm²,the initial toluene gas concentration was 50ppm,reaction temperature was25?,air flow rate was 0.5m/s,reaction time was 3h,light radiation illuminance was28.91W/m² and Co²⁺doping ratio in Co²⁺/AgNbO₃ was 1%,the optimal toluene gas removal efficiency of Co²⁺/AgNbO₃ was 74%,10.72%higher than the value of the single AgNbO₃.While the corresponding value of the porous TiO₂ was 46.98%under the same condition.However,the optimal toluene gas removal efficiency of Co²⁺/AgNbO₃/porous TiO₂ composite photocatalyst materials was up to 92.28%,which were prepared with a mass ratio of 2:5(Co²⁺/AgNbO₃ to porous TiO₂),and calcination for 4h at 500?,45.30%and 18.28%higher than the toluene gas removal efficiency of single porous TiO₂ and Co²⁺/AgNbO₃ composite materials,respectively.Besides,toluene gas removal performance of the Co²⁺/AgNbO₃/porous TiO₂composite photocatalyst materials in diffierent the photocatalyst dosage and initial concentrations of toluene gas was discussed.Results showed that the optimal rate of toluene gas was 93.98%and 95.36%respectively when the Co²⁺/AgNbO₃/porous TiO₂composite photocatalyst dosage was 0.033g/cm² and the initial concentration of pollutants was 75ppm.