【作者】 王琼；

【导师】 张吕鸿；

【作者基本信息】 天津大学 ， 化学工程， 2010， 硕士

【摘要】 本文以自制磺化煤为载体,以氨水为沉淀剂,以Ti（SO4）2为前驱体,采用微波-液相沉淀法,制备了iO2/磺化煤复合光催化剂。并通过透射电子显微镜（TEM）、X射线衍射（XRD）及带有能谱分析（EDS）的扫描电子显微镜（SEM）等手段对其形貌和成分等进行了表征。研究了首次微波功率、首次微波时间、磺化煤粒径大小、负载比、水浴时间、TiO₂沉淀析出时液相的pH值等条件,对样品特性和光催化活性的影响,并探讨了样品对甲基橙水溶液的吸附行为。XRD表征结果表明,负载到磺化煤上的纳米TiO₂为单一的锐钛矿,具有很高的结晶度,晶粒分布较窄,集中在4.0 nm左右。通过正交试验研究,发现首次微波功率对晶体的晶粒尺寸和结晶度的影响最大,说明在不经高温煅烧的条件下,微波取代传统加热不仅提供了热源,还对晶体的成核和生长有重要的促进作用。通过单因素试验的研究,发现首次微波时间对晶粒尺寸的影响较大,纳米晶体TiO₂在首次微波时间为45 min时就有很高的结晶度;延长水浴时间或控制TiO₂沉淀析出时液相的pH值在6～9之间都对晶体成核有利;TiO₂沉淀析出时的液相pH值在6～9范围内时,与晶体的粒径大小呈正相关。通过研究样品对甲级橙水溶液的吸附行为,得出吸附过程为放热的物理吸附,吸附热为-9.229 J/mol。通过研究样品对甲基橙水溶液的光催化降解反应,分析了反应的动力学特征,发现样品对甲基橙的光催化降解反应符合一级反应动力学,并将拟合得到的表观反应速率常数K作为样品光催化活性高低的判据。研究表明,TiO₂/磺化煤复合光催化剂中纳米TiO₂的晶粒尺寸和结晶度与它的光催化活性之间存在正相关。通过多次光催化实验研究,发现样品经多次光催化后仍然具有很好的光催化活性和稳定性。更多还原

【Abstract】 In this paper, nano-TiO₂ was successfully loaded on sulfonated coal by the liquid phase deposition method under the help of microwave radiation with sulfonated coal chosen as the supporter, ammonia as the precipitator and Ti（SO4）2 as precursor. The components and morphology of the as-gained samples were characterized by the high resolution transmission electron microscopy （HRTEM）, X-ray diffraction （XRD）, and the scanning electron microscope （SEM） with energy dispersive spectrometer （EDS）. The effects of the size of sulfonated coal, the mass ratio of sulfonated coal to theoretical yield of TiO₂, the firstly microwave radiation power and its time, as well as the bathing time, and the pH value of the solution when TiO₂ deposited on the particle sizes of nano-TiO₂, its morphology, crystallinity and its photocatalytic activity, the etc. were investigated in this paper. The adsorption behavior of methyl orange by the gained samples was also discussed.It was revealed by the XRD results that nano-TiO₂ particles coated on the supporters were pure anatase with high crystallinity and a narrow distribution of sizes around 4.0 nm.The orthogonal test manifested that the firstly microwave radiation power among the three discussed factors had the strongest effect on the particle size and crystallinity of nano-TiO₂ which indicated that microwave radiation without sintering at high temperature in place of conventional heating methods not only provided the heat necessary for the synthesis, but also impelled the nucleus formation and growth of the crystal.The single factor variants experiment showed that the time of firstly microwave radiation had a very strong influence on the particle sizes while almost had no influence on the crystallinity; prolonging the bathing time or keeping the pH value of the solution when TiO₂ precipitated between 6～9 were in favor of the nucleus formation of the crystal; a positive relationship between the pH value, in the range of 6 to 9, of the solution when TiO₂ precipitated and the particle sizes of nano-TiO₂ was discovered.It was observed that the adsorption of methyl orange by the samples belonged to physical adsorption, releasing 9.229 Joule per mole.The kinetic character of the photocatalytic degradation of methyl orange in aqueous suspension by the as-gained samples under ultraviolet light was researched and it was discovered that the photocatalytic reaction obeyed the first-order kinetic reaction equation; the apparent reaction rate constant was used to judge the photocatalytic activity of the as-gained samples. It was confirmed that the sizes and crystallinity of nano-TiO₂ particles loaded on the sulfonated coal had a positive relationship with its photocatalytic activity.The study of repeatedly used samples in photocatalytic experiment showed that the as-gained samples had a quite good photocatalytic activity and performed strong stability.更多还原