Hydrothermal Synthesize And Visible Photocatalys-Tic Activities Of Nanocrystals Spinel Aluminate

Photocatalytic oxidation is a technique for removal of pollutants from aqueous and airstream by using the semiconductors photocatalyst. Its can provide new methods for theindustrialized treatment of organic pollutions and has widely used because of high-efficiency,easily controlled operation conditions, non-selective degradation, no secondary pollution. Atpresent, the semiconductor photocatalysts (like TiO2) with wide band gap are merelyresponded ultraviolet spectrum. It is difficult to accomplish availably transform and utilizationof solar energy. So developing a new visable light response semiconductor photocatalysts(spinel-type AB2O4) becomes a new researchful hot spot about photocatalyst research.In this paper, the spinel-type aluminous series compounds NAl2O4(N=Zn,Cu,Ni) areprepared by hydrothermal method. With XRD, TEM and UV-vis DRS testing means, weinvestigate the framework of crystal, the external figure and the light response bound. Thephoto-degradation experiments of various water-soluble dyes including Methyl Orange,Reactive brilliane red K-2G, acid red B are carried out in the suspension systems of spinelsacting as photocatalysts. The photocatalytic activity of various spinels is described by thedecolored rate and the COD removed rate of dyes. Spinel-type ZnAl2O4photocatalystprepared by hydrothermal method with the better photocatalytic character is studiedparticularly. The impact of the hydrothermal conditions and the photocatalyst dosage upon itsphotocatalytic character is discussed.The results show that spinel-type NiAl2O4、ZnAl2O4compounds can be synthesized inthe lower temperature by hydrothermal method, but CuAl2O4samples are prepared by heattreatment. By the study of photocatalytic activity of NAl2O4(N=Zn,Cu,Ni) samples, it isfound that the degradation rate and COD removed rate for those three dyes is excellent, in2htwo value can reach80%and50％above, the diversity of the photocatalytic activity anddegradation velocity for them is explained by the ion semidiameter of N location element,d-electron number of the element(N) and the band gap(Eg) of NAl2O4(N=Zn,Cu,Ni) samples.The analysis of photocatalytic activity of ZnAl2O4sample indicates that the impact of thehydrothermal temperature and pH value upon its photocatalytic activity is biggish. When the hydrothermal temperature is245℃and pH value is10, ZnAl2O4sample has the bestdegradation effect, the degradation rate comes to90％above. But the hydrothermal time isn’timportant factor, the degradation rate of Methyl Orange has small variety with prolonging thereaction time. The impact of the photocatalyst dosage on its photocatalytic character is takeninto account. The effect of the degradation is best when the dosage of CuAl2O4photocatalystis confirmed in2g/L.