| At present, the human face increasingly serious environmental pollution problems. So, Pollution control has become the hotspot. Because there maybe secondary pollution or incomplete decomposition in traditional treatment methods. People begin to search for new treatment methods, photocatalytic technology was found as an efficient treatment methods. Thereinto, spinel-type photocatalytic materials was widely noticed as which partially overcome the light corrosion of treatment photocatalytic materials. But, the research of spinel-type photocatalytic materials is still in its early stages, there was no full understanding of preparation for its perfect and reasonable modification means. So, This article will systematic study CuAl2O4 and ZnAl2O4 two kinds of spinel materials, search for the photocatalytic activity and preparation of CuAl2O4 and ZnAl2O4:One, study on CuAl2O4 powder:this article will systematicly study material ratio, sintering temperature, sintering time, stirring time, pH, sintering atmosphere, the amount of dispersant, sulfate dispose, refrigeration entironment of CuAl2O4 powder, for founding the best preparation conditions and obtaining better performance of CuAl2O4 powder, at the same time, provide the basis for its application. The crystalline structure were characterized by powder X-ray diffraction, molecular groups were identified by FTIR, components were identified by XPS, heat treatment process were analysised by TG-DTA, surface area were tested by BET. The photocatalytic degradation and adsorption were investigated by using methyl orange, under the irradiation of mercury-vapor lamp. By UV-Vis diffuse reflectance results of the photocatalytic were tested. At the same time, the performance of repetitive samples, adsorption and particle size.The result of X-ray diffraction exhibit a spinel-type structure and Prove the existence of Cu2O (SO4) crystal. From the result of performance testing we can see that, CuAl2O4 powder have better photocatalytic activity which were sintered at 700℃for 2 h and under the reducing atmosphere, stirred for 30 minutes, the amount of dispersant ratio cation=2:1, pH=1.9, sulfate disposed for 1 h. Decolorization rate of CuAl2O4 powder reached 90%(it contains 30% of the adsorption). I think that CuAl2O4 powder have better photocatalytic activity under visible light, Cu2O(SO4) crystal improve photocatalytic activity of CuAl2O4 powder, there are two reasons:on the one hand, Cu2O(SO4) crystal provide acidic environment,which increased large numbers of the electron-hole pairs by CuAl2O4 powder acidification and. On the other hand, Cu2O(SO4) crystal provide CuO crystal, which improve the photocatalytic activity of CuAl2O4 powder under the high temperature by CuO crystal negative temperature coefficient effect.Two:study on ZnAl2O4 powder:this article will systematicly study sintering temperature, drying temperature, sintering time, stirring time before dispersant added, stirring time after dispersant added, pH, drying time of ZnAl2O4 powder, for founding the best optimization preparation conditions and obtaining better performance of ZnAl2O4 powder, at the same time, provide the basis for synthesising of the other pinel-type photocatalytic materials. The crystalline structure were characterized by powder X-ray diffraction, molecular groups were identified by FTIR, surface area were tested by BET. The photocatalytic degradation and adsorption were investigated by using methyl orange, under the irradiation of UV light. At the same time, By UV-Vis diffuse reflectance results of the photocatalytic were tested and the performance of repetitive samples were measured.The result of X-ray diffraction exhibit a spinel-type structure and Prove the existence of ZnAl2O4 crystal. We can see that ZnAl2O4 powder were sintered at 600℃, which have the larger surface area then others. From the result of performance testing we can see that, ZnAl2O4 powder have better photocatalytic activity which were sintered at 600℃for 3 h, stirred for 30 minutes before and afer dispersant added, dried at 120℃for 6 h, pH=1.6. Decolorization rate of ZnAl2O4 powder arrived 90%.Summing up, this article will synthesized CuAl2O4 and ZnAl2O4 powders by the inorganic salt sol-gel method, throuth systematicly study a variety of conditions about effects of sol-gel system, to obtain the best optimizative photocatalytic activity of CuAl2O4 and ZnAl2O4 powders, for supplying new the raw materials choices in pollution controlled. In particular, CuAl2O4 powder have significant photocatalytic activity, It not only have high photocatalytic efficiency and strong stability performance, but also have high photocatalytic efficiency under the visible light which significantly reduced the limits of photocatalytic materials in application and the costs of photocatalytic pollution problems. At the same time, Cu2O(SO4) crystal can improve photocatalytic activity of CuAl2O4 powder, which provide the basis on modification of photocatalysis materials. In addition, appropriate acidification can increase large numbers of the electron-hole pairs in photocatalysis materials, to arrive strengthening effect of photocatalytic activity. Furthermore, the ambient temperature of photocatalytic reactiono ccurred dramatically affect photocatalytic activity, which due to temperature coefficient effect of crystal. Spinel-type crystal have better photocatalytic activity at low temperature with positive temperature coefficient effect. Throuth systematicly studying, we successfully synthesized new type photocatalysis materials, obtain the best optimizative preparation conditions of new type photocatalysis materials, find the better methods of modification of photocatalysis materials, provide the basis on in-depth study of spinel-type photocatalysis materials. |
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