【作者】 徐慧娟；

【导师】 蒋月秀；

【作者基本信息】 广西大学 ， 应用化学， 2008， 硕士

【摘要】 本论文以钠化膨润土为载体,采用溶胶-凝胶法在微波辅助下制备了金属离子掺杂TiO₂/膨润土光催化剂;通过X射线粉末衍射（XRD）、比表面测定（BET）、红外光谱（IR）等分析方法对催化剂进行了表征,以偶氮类的甲基橙溶液和糖蜜酒精废液作为目标降解物,考察了催化剂的光催化性能,主要结论如下:微波辅助下Fe-TiO₂/膨润土光催化剂的最佳制备条件为:微波加热功率为750w,钛酸丁酯溶液水解过程微波辐射5min,凝胶干燥过程微波辐射8min,550℃焙烧1.5h。XRD分析表明,与常规加热法相比,微波辅助下制备的光催化剂中TiO₂的粒径较小;Fe³⁺、Ni²⁺离子的掺杂促进了TiO₂由锐钛矿相向金红石相的转变,La³⁺离子的掺杂则抑制了TiO₂的这种相转变;Fe³⁺、Ni²⁺、La³⁺离子的掺杂均抑制了TiO₂颗粒的长大。IR分析发现,Ti⁴⁺离子与膨润土载体发生了化学键合;BET测定表明,焙烧温度550℃时,与常规加热法制备的Fe-TiO₂/膨润土催化剂相比,微波加热法制备的催化剂比表面积有显著提高。甲基橙光催化剂降解实验表明,微波加热法比常规加热法制备的Fe-TiO₂/膨润土催化剂活性高。当Fe-TiO₂/膨润土光催化剂用量为2.5g/L,甲基橙溶液初始浓度为20mg/L,pH值为4.21,Fe的掺杂浓度为0.20%,光催化反应时间为60min时,甲基橙溶液的脱色率可达96.13%。催化剂的重复使用效果表明,催化剂的活性具有较高的稳定性,能重复使用,可以有效降低催化剂使用成本。动力学研究表明,在实验浓度范围内,该光催化反应可用一级反应动力学方程描述。Fe-TiO₂/膨润土光催化剂对糖蜜酒精废液降解实验表明:糖蜜酒精废液稀释30倍,Fe-TiO₂/膨润土催化剂用量为2.5g/L,初始pH值为溶液自然pH值,外加氧化剂H₂O₂投加量为3.0ml/L,光照2h后糖蜜酒精废液脱色率可达82.94%。更多还原

【Abstract】 In this paper,a sodium-type modified bentonite was used as carrier to prepare metal ion doped TiO₂/bentonite photocatalyst by microwave-assisted sol-gel method. Modern techniques such as X-ray powder diffraction（XRD）,specific surface area （BET）determination and infra-red spectra（IR）were applied to characterize the photocatalyst,the photocatalytic behavior in degradation reactions of methyl-orange solution and of molasses alcohol wastewater were studied.Several conclusions can be drawn as follows.The optimum conditions of Fe-TiO₂/bentonite photocatalyst prepared by microwave-assisted method were microwave power 750w,tetrabutyl titanate hydrolysis process microwave radiation 5 min,gel drying process microwave radiation 8 min,calcining temperature 550℃,calcining time1.5h.XRD reveals that the size of TiO₂ particles in Fe-TiO₂/bentonite prepared by microwave-assisted method is smaller than those prepared by conventional method. Fe³⁺and Ni²⁺doping can promote phase transformation of TiO₂ from anatase to rutile, but La³⁺doping inhibits this phase transformation of TiO₂,Fe³⁺,Ni²⁺and La³⁺ doping restrain the increase of the grain size of TiO₂.Infra-red spectra（IR）information indicated that titanium bond to the bentonite.BET analysis shows that specific surface area of Fe-TiO₂/bentonite prepared by microwave-assisted method is much larger than that prepared by conventional method.The degradation reaction of methyl-orange solution catalyzed by Fe-TiO₂/bentonite shows that the photocatalytic activity of Fe-TiO₂/bentonite prepared by microwave-assisted method is higher than that of prepared by conventional method,under conditions of Fe-TiO₂/bentonite 2.5g/L,the initial concentration of methyl-orange in solution 20mg/L,the solution pH=4,illumination time 60 min,the degradation rate of methyl-orange is 96.13%.The repeatedly use of the photocatalyst shows that it is catalytically stable during degradation reaction,can be re-used and cause lower costs.The photocatalytic degradation reaction of methyl-orange solution can be expressed as first-order kinetic mode within the concentration range of methyl-orange solution between 20mg/L and 50 mg/L.The degradation reaction of molasses alcohol wastewater catalyzed by Fe-TiO₂/bentonite results that under conditions of dilution 30times,Fe-TiO₂/bentonite catalyst 2.5g/L,original pH,H₂O₂ oxidant consumption 3.0mL/L,illumination time 2h,the degradation rate of molasses alcohol wastewater is 82.94%.更多还原