摘要:本文以凹凸棒石(ATP)为载体，钛酸四丁酯和六水合硝酸铈为原料，采用溶胶-凝胶法制备ATP/CeO2-TiO2纳米复合材料。通过TG、TEM、XRD、FTIR、N2吸附脱附等测试手段对样品的微观结构进行表征。以罗丹明B为模拟废水进行了催化降解实验，考察复合材料的催化性能并对其催化氧化机理进行初步探讨。
研究表明，对ATP/CeO2-TiO2纳米复合材料而言，当铈钛摩尔比≥3:7时，铈钛氧化物可以形成固溶体均匀负载于ATP表面。最佳煅烧温度在400 ℃左右，过高的煅烧温度会造成凹凸棒石载体塌陷；而过低的煅烧温度会使氧化物无法获得较好的结晶度。当铈钛摩尔比为5:5，溶胶-凝胶反应温度为30 ℃，煅烧温度为400 ℃时，氧化物均匀分散在ATP表面，得到具有介孔结构的ATP/CeO2-TiO2复合材料。这种复合材料具有较好的催化性能，以臭氧为氧化剂，对罗丹明B模拟有机废水溶液的COD降解率达93%。
关键词：凹凸棒石；溶胶-凝胶；ATP/CeO2-TiO2；催化降解
Abstract:In this research, ATP/CeO2-TiO2 nanocomposites were synthesized by sol-gel method using ATP as support, cerium nitrate hexahydrate, tetrabutyl titanate as raw materials. The microstructures of the as-prepared nanocomposites were characterized by thermogravimetric (TG), transmission electron microscopy (TEM), X-ray diffraction (XRD), fourier transform infrared spectrometer (FTIR), N2 sorption-desorption. The catalytic oxidation properties of ATP/CeO2-TiO2 could be determined by the degradation test of Rhodamine B, the simulated wastes and the catalytic mechanism of ATP/CeO2-TiO2 nanocomposites was analyzed in this discussion.
Results showed that the solid solution of Ce and Ti oxides were loaded on the surface of ATP evenly in the case of Ce:Ti(molal ratio)≥3:7. The optimized calcination temperature was found around 400 ℃. The higher calcination temperature led to the collapse of ATP, on the contrary, lower calcination temperature would impede the oxides to get a higher degree of crystallinity. Well-defined ATP/CeO2-TiO2 nanocomposites owning mesoporous structure can be prepared successfully, when Ce:Ti(molal ratio) was 5:5 and the sol-gel temperature was 30 ℃. This nanocomposites demonstrated enhanced catalytic property as compared to ATP/CeO2 and ATP/TiO2. The COD removal efficiency of ATP/CeO2-TiO2(Ce:Ti=5:5) for Rhodamine B could reach 93%.
Key words: attapulgite; sol-gel; ATP/CeO2-TiO2; catalytic degradation
