| The mist widely raged, and water pollution or other environmental problemsincreasingly standed out, these make people more and more attention to the health ofour environment. Water, in particular, is closely related to our life, so looking for agentle and effective solution is very important. With a lot of research practice, theresearcher found semiconductor photocatalyst oxidation technology than othertechnology for remedying environmental pollution is more moderate, degradationcompletely and has no secondary pollution. With the increasingly improvement ofTiO2semiconductor research in recent years, people begin to pay more attention tothe new-typed semiconductor photocatalyst and doped semiconductor research ofcomposite photocatalyst.This paper mainly research the structure and properties of visible light catalyst ofone new type semiconductor photocatalyst that is a compound consisting of Bi2WO6and natural diatomite that is a porous silica material. This combination both haverespective advantages, not only retained the photocatalytic activity of bismuthtungsten, but also solved the recycling of the product. Through the experimentresearch we will find the optimal conditions of synthesis, the influence of Cu,Fe, Pbdoped composite product and the structure or performance influence of product thatuse diatomite under different roasting process as carriers. And using a variety ofcharacterization methods, such as XRD, FTIR, SEM and optical test, and thesynthetic structure, crystal structure, composition analysis of samples are measured.1. In order to prepare Bi2WO6/diatomite composite photocatalyst,I adopte thecombination of hydro-thermal method, and the result showed that the optimalconditions is: the pretreatment of the purified diatomite calcination temperature is600℃, pH=2, hot water for24h, and the optimal complex ratio of Bi2WO6-60%, anddiatomite-40%, under this condition of synthesis,the product reach best interfacebonding state. 2. Through the photocatalytic tests, the ratio of the product in hydro-thermalsynthesis and dye solution joined is1g/L. The results showed that photocatalyst ofBW-60/d-40/pH-2photocatalytic activity, slightly higher than pure Bi2WO6catalystof the same condition preparation, the degradation rate was79%.3.Three kinds of Cu, Fe, Pb metal salt doped in the best preparation conditions:600℃and aerobic calcined diatomite as carrier, the precursor solution pH=2, theload ratio of60%.On the basis of the above conditions,I study the structure andcatalytic activity of BW-60/d-40composite photocatalyst doped with Pb, Cu, Fe.Doping Fe and Pb are both making photocatalytic performance of composite sampleshigh than BW-60/d-40, and the best mix of: Pb/2%-degradation rate90.8%,Fe/5%-degradation rate88.5%, Cu/0.5%-degradation rate70.6%.Pb elementinvolved more efficient to improve the photocatalytic performance of the Bi2WO6/diatomite. Through a variety of characterization methods, the Pb element comparedwith other two kinds of mixed into synthetic samples is more influene.4. Because of the innovation of this reacher that carries the diatomite as carrier ofthe compound semiconductor photocatalyst, this paper mainly discusses the influenceof the Bi2WO6/diatomite composite photocatalyst under the diatomite roastingmethods and different calcination temperature. Through aerobic and two types ofroasting, carbide and calcined at different temperatures of diatomite, two kinds ofdiatomite was studied under different temperature adsorption performance, observedthe surface structural changes etc. Conclusion: carbonized diatomite adsorptionperformance is better than aerobic diatomite, aerobic after calcined diatomite, thesurface and hole of the residual organic volatile, the pore structure is clear, and withthe increase of aerobic roasting temperature, diatomite interlayer structure destruction,carbonization of the surface of the diatomite after still attached to some material, mayfor organic matter in anaerobic conditions, carbide and along with the increase ofcalcination temperature, pore structure on the surface of the diatomite graduallynarrowed. At600℃carbonization of diatomite as carrier, precursor pH=2, load ratiois60%tungsten acid bismuth, photocatalytic performance that is prepared withBi2WO6/the carbonized diatomite composite photocatalyst is stronger, thedegradation rate was82%, and the degradation rate of the best BW-60/d-40-CY600 ℃is bigger, the carbonization process of diatomite enhances the photocatalyticactivity of composite photocatalyst. |
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