Study On Photocatalytic Properties Of Nano-TiO₂ Supported By Alumina Foam Ceramics

Based on the disadvantages of nano titanium dioxide(nano-TiO₂)powder,the alumina foam ceramics/nano-TiO₂(AFC/nano-TiO₂)composite materials were prepared by sol-gel method with the process of dipping titanium sols,drying and calcination.The photocatalytic properties of the AFC/nano-TiO₂composite materials were studied.The details of the study were as follows:(1)Titanium sols were synthesized by sol-gel method,and nano-TiO₂was prepared by gelation,drying and firing processes.The effects of mixed droplet acceleration,titanium sols concentration and titanium gels calcination temperature on the properties of nano-TiO₂ were investigated.The results showed that when the mixed droplet acceleration rate was 1drop/second,the titanium sols concentration was 0.3336 mol/L and the calcination temperature was 450?,the nano-TiO₂ prepared was all anatase type with a grain size of about 20 nm and had the best photocatalytic performance.(2)The effects of nano-TiO₂ powder mass concentration,light intensity,p H value,titanium sols concentration and titanium gels calcination temperature on the photocatalytic performance of nano-TiO₂powder were studied using rhodamine B(RhB)solution as the degradation substance.The results showed that with the increase of nano-TiO₂ powder dosage,the degradation effect of nano-TiO₂ powder photocatalytic degradation of RhB solution showed a trend of increasing first and then decreasing,and the best photocatalytic degradation effect was achieved when the mass concentration of nano-TiO₂ powder was3.5g/L.With the increase of light intensity,the degradation efficiency of nano-TiO₂ powder on RhB solution increased.When the distance between the reaction vessel and the light source was 20 cm and the p H value was neutral,the nano-TiO₂ powder photocatalyst had the best photocatalytic degradation performance for RhB solution,and its degradation rate was more than 2.6 times than that of P25(Evonik Degussa)powder.(3)AFC/nano-TiO₂ composite materials with photocatalytic properties were prepared by impregnation process.The effects of loading rate,titanium sols concentration,calcination temperature,number of impregnations,light intensity and stability of the material on the photocatalytic performance of AFC/nano-TiO₂ composite materials were investigated.The results showed that the single loading rate of AFC/nano-TiO₂ composite materials was greater than 0.1%,and the higher the titanium sols concentration,the greater the loading rate.With the decrease of titanium sols concentration and the increase of calcination temperature,the degradation rate of AFC/nano-TiO₂ composite materials to RhB solution showed a trend of increasing first and then decreasing,and when the titanium sols concentration was 0.3336 mol/L and the calcination temperature was 450?,the AFC/nano-TiO₂ composite materials had the best photocatalytic degradation effect,and its photocatalytic degradation of RhB solution The degradation rate was more than 1.2 times that of the AFC/P25 composite materials.With the enhancement of light intensity,the degradation rate of AFC/nano-TiO₂composite materials for degrading RhB solution also increased gradually.With the increase of impregnation times,the loading rate of AFC/nano-TiO₂ composite materials increased,while the degradation rate of AFC/nano-TiO₂ composite materials to RhB solution showed a trend of first increasing and then decreasing,and when the impregnation times were 4 times,the AFC/nano-TiO₂ composite materials had the best photocatalytic degradation effect,and after 240 min of UV irradiation,the The degradation rate of photocatalytic degradation of RhB solution was96.29%.After the AFC/nano-TiO₂ composite materials were recycled for5 times,the degradation rate of AFC/nano-TiO₂ composite materials to RhB solution was 85.29%,which had good stability and photocatalytic activity.