Preparation And Doping Modification Of TiO2Photocatalysts By Fly Ash Cenospheres As Carrier

TiO2has been widely used as an ideal photocatalyst, because of its chemical stability, high photocatalytic activity, low cost and nontocicity. The band gap of TiO2however is wide (3.2eV), it can only be excited by UV light (λ<387nm). Its utilization capacity for solar energy is very low and its quantum efficiency low either.In this paper, with (Tx-100, oleic acid)/n-butanol/cyclohexane/H2O as microemulsion syetem, adopting cheap TiCl4as the raw material, fly ash cenospheress of Huainan power plant as the carrier, the loaded Ce4+, Co2+, La3+and Fe3+doped TiO2photocatalysts were prepared. The influence of kinds of doping ions, ion doping concentration, pH value, the load of catalyst, the deposit times of TiO2, and the time of catalyst regeneration on photocatalytic degradation of methyl orange were investigated. The crystallization temperature of the precursors was characterized by differential scanning calorimetric-thermo-gravimetric analysis(DSC-TG). The composition of catalyst was characterized by X-ray diffraction(XRD). The functional groups were characterized by fourier transform infrared spectrometer(FTIR). The morphology of particles was analysised by scanning electron microscopy(SEM). The content of the various elements in the supported catalyst was determined by EDS. The spectralabsorption of catalyst was characterized by UV-Vis.The results show that the key factors of effect (La3+, Fe3+)-TiO2/cenospheress catalyst performance was precursor calcination temperature and the loading times. The crystal form of TiO2was determined by calcination temperature. The samples are the mixture of anatase and rutile when the precursor calcined at500℃. Only35.67%of the time on TiO2coating rate. The second load of catalyst have a higher photocatalytic activity because the catalyst surface electorn-hole increased and Ti-O-X(Si,Fe,La) bridge oxygen bonds also increased.(La3+, Fe3+)-TiO2/cenospheress catalyst can be uniformly dispersed in the solution of methyl orange.(La3+, Fe3+)-TiO2/cenospheress composite catalyst of methyl orange degradation rate of93.2%when the amount of catalyst is7.5g/L, pH4and on the UV-Vis lamp reaction90min. In sunlight exposure6h methyl orange degradation rate was50.6%. Circulation five time catalyst degradation rate of80%.This study shows that, La3+,Fe3+co-doped nano-TiO2catalyst oreoaration and modified set in one step by microemulsion solved the catalyst immobilization and recycling utilization. And the method is simple, equipment requirements low. Fly ash cenospheres as the carrier efficient use of power plant emissions waste, and inexpensive source of raw materials enhanced the usability of the catalyst. La3+,Fe3+co-doped TiO2spectral absorption range move to the visible light and photocatalytic degration ability.Fig37, Table10, Reference68...