铜铁共掺杂TiO2/膨润土光催化剂的制备及光催化性能

以溶胶-凝胶法、液相沉淀法和机械混合法制备了Cu-Fe双金属掺杂的TiO2/膨润土复合光催化剂,采用XRD、FTIR对其进行了结构表征,以紫外光和可见光催化降解直接天蓝染料废水为模型,考察了制备方法对催化剂光催化性能的影响。结果表明:各催化剂中均有锐钛矿型TiO2生成,且部分TiO2进入了膨润土的蒙脱石层间,改变了其层间的有序性,生成了Ti—O—Si键,实现了TiO2粒子与膨润土的复合。溶胶-凝胶法制备的催化剂中TiO2与膨润土的复合程度最高,Cu2+和Fe3+成功掺入了TiO2晶格,形成了复合半导体,拓宽了TiO2的光谱响应范围,使该催化剂表现出最优的光催化活性,并且该催化剂性能稳定,易于沉降分离,经高温活化再生后仍具有良好的催化活性,可重复多次使用,表现出良好的再生性能。

Preparation and characterization of Cu-Fe co-doped TiO2/bentonite photocatalyst

The paper is aimed at presenting our research results on the enhancement of photocatalytic activity of modified TiO2 photocatalyst under visible light and its regeneration capacity.First of all,Cu-Fe-TiO2/bentonite composite photocatalysts were prepared by sol-gel,liquid phase precipitation and mechanical mixing method,respectively.Next,by using the degradation of direct sky blue dye wastewater as a model,the photocatalytic properties of samples obtained through different preparation methods were investigated under visible and ultraviolet light.Finally,XRD and FTIR were employed to characterize the structure of the samples.The results show that the preparation methods have a significant influence on the photocatalytic performance of Cu-Fe-TiO2/bentonite catalysts and the catalyst prepared by sol-gel method shows highest photocatalytic activity.When the initial concentration of direct sky blue was 50 mg/L and illumination time was 1.5 h,the decolorization rate of direct sky blue solution under visible light irradiation(97.3%) was in close proximity to that of ultraviolet light(98.6%).This is mainly attributed to the higher degree of compositing of TiO2 particles with bentonite,and the Cu2+and Fe3+ions incorporate into the lattice structure of anatase TiO2 and partially replace Ti4+,Thus,the ternary compound semiconductor was formed.Besides,the results also show that the sol-gel method has enhanced the formation of lattice defects of TiO2 and produced a synergic effect between the Cu-Fe,TiO2 and bentonite.In the catalyst prepared by sol-gel method,the high surface area of bentonite which works well as an effective adsorbent,concentrates direct sky blue dye molecules around the loaded TiO2.The Cu2+and Fe3+ions which are used as dopants,after incorporated into the TiO2 lattice,can induce the formation of lattice defects then modify the band gap of TiO2.They act as charge separators of the photoinduced electron-hole pairs and thus enhance the photocatalytic activity under visible light.In addition,the performance of prepared catalyst is stable,easy to settle down and separate.It is reusable by subjecting to high temperature activation.Therefore,the catalyst has a potential application in water treatment technology.