【作者】 王宁；

【导师】 李保山；

【作者基本信息】 北京化工大学 ， 化学工程与技术， 2018， 硕士

【摘要】 进入新世纪以来,材料革命蓬勃兴起。设计、制备和应用新型材料已经成为了工业产业升级发展的基石。把握新材料技术便是把握未来的主动权。光能作为重要的绿色能源,是我国能源战略中的重要一环。传统光催化剂主要是具有紫外响应的半导体材料,存在吸附能力差、比表面积小等缺点,使其应用受到诸多桎梏。多级复合材料由于其多级结构和功能复合的优势,受到越来越多的关注和青睐。分子筛由于其孔道结构与骨架特征,在工业催化领域中广泛应用。但微孔除了具有优异的择形选择性外,也极大地迟滞了反应过程中的物质传输。缩短扩散路径,设计和制备具有多级孔道体系的分子筛,近年来已经成为分子筛研究的热点课题。过渡金属改性是分子筛改性的重要方法。结合两者的优势,研究具有多级孔道结构的过渡金属改性分子筛材料便具有重要的现实意义。本文通过晶种辅助法可控制备了系列多级孔MnAPSO-34分子筛;通过微乳软模板法可控制备了新颖的杨梅形TiO2/SiO2多级复合纳米球。详尽探索了两种多级孔复合材料的的最佳工艺条件和方法技术,并对其光催化降解性能进行了评价。本论文的主要工作和所取得的成果:1.以二乙胺作为结构导向剂,通过晶种辅助法可控制备了具有微孔-大孔复合结构的多级孔SAPO-34分子筛,粒径约3.64 μm。研究了其多级孔结构的形成过程。探究了结构导向剂、硅含量以及晶种用量等因素对材料的孔道结构和表面特性的影响,获得了一系列有规律的结果。2.在晶种辅助的基础上结合过渡金属改性工艺,可控制备了系列多级孔MnAPSO-34分子筛。详细探究了结构导向剂种类、锰含量等因素对材料结构和性质的影响。并以亚甲基蓝作为探针,探讨了其对有机污染物可见光降解行为。Mn/Al2O3=0.15样品的光催化活性最佳,可见光辐照300 min后,0.05 g催化剂对50 mL 1Omg·L-1亚甲基蓝溶液的降解率达80.04%,具有良好的循环降解活性和稳定性。3.以乙酸乙酯与十六烷基三甲基溴化铵形成的微乳液为软模板制备了新颖的杨梅形SiO2多级纳米球。以不同钛硅比的混合前驱体溶液,通过软模板法制备了杨梅形TiO2/SiO2多级复合纳米球。探究了正辛烷用量、氨水浓度和钛硅比例等因素对材料形貌和结构的影响。并以罗丹明B作为探针,详细考察了其对有机污染物紫外光降解行为。Si/Ti=3样品的光催化活性最佳,紫外光辐照120 min后,0.05 g催化剂对50 mL 20 mg·L-1罗丹明B溶液的降解率达96.73%。更多还原

【Abstract】 Since the beginning of new century,material revolution has been flourishing.Design,preparation and application of new materials has become a cornerstone of the upgrading and development of the industry.Grasping the new material technology is the initiative to grasp the future development.As an important green energy source,light energy has been an important part of China’s energy strategy.Traditional photocatalysts are mainly semiconductor materials with ultraviolet response,which have the disadvantages of poor adsorption capacity and small specific surface area,which’ make their application suffer from many defects.Hierarchical composite materials have received more and more attention due to their hierarchical structure and functional composite advantages.Molecular sieves are widely used in the field of industrial catalysis because of their pore structure and skeleton characteristics.In addition to excellent shape selectivity,the micropores of the molecular sieve also greatly retard the material transport during the reaction.Shortening the diffusion path and designing and preparing molecular sieves with hierarchical pore systems have become hot topics in molecular sieve research in recent years.Transition metal modification is an important method of molecular sieve modification.Combining the advantages of both,it is of great practical significance to study transition metal-modified molecular sieve materials with hierarchical pore structure.In this paper,a series of hierarchical MnAPSO-34 molecular sieves were controllably prepared by the seed-assisted method,and a novel waxberry-shaped TiO2/SiO2 hierarchical composite nanosphere was controllably prepared by the microemulsion soft-template method.The optimum process conditions and methods for the two hierarchical composite materials were explored in detail,and their photocatalytic degradation performance was evaluated.The main work of this paper and the results achieved:1.Using diethylamine as a structure-directing agent,a hierarchical SAPO-34 molecular sieve with a micropore-macroporous composite structure was controllably prepared by seed-assisted method,and the particle size was about 3.64μm.The formation process of hierarchical structure was studied in detail.The effects of structure-directing agents,silicon content and amount of seeds on the pore structure and surface properties of the material were investigated,and a series of regular results were obtained.2.A series of hierarchical MnAPSO-34 molecular sieves were controllably prepared on the basis of seed-assisted combination of transition metal modification process.The influence of the structure-directing agent type,manganese content and other factors on the structure and properties of the material was investigated in detail.With methylene blue as a probe,its visible light degradation behavior of organic pollutants was investigated.The photocatalytic activity of Mn/Al2O3=0.15 was the best.After 300 min of visible light irradiation,the degradation rate of 0.05 g catalyst to 50 mL of 0.01 g·L-1 methylene blue solution was 80.04%,which shows good cyclic degradation activity and stability.3.A novel waxberry-shaped SiO2 hierarchical nanospheres was prepared using a microemulsion formed from ethyl acetate and cetyltrimethylammonium bromide as soft templates.In the mixed precursor solution with different titanium-silicon ratio,the waxberry-shaped TiO2/SiO2 hierarchical composite nanospheres were prepared by soft-template method.The effects of the amount of n-octane,the concentration of ammonia,and the ratio of titanium to silicon on the morphology and structure of the material were investigated.And using Rhodamine B as a probe,its UV degradation behavior of organic pollutants was investigated in detail.The photocatalytic activity of Si/Ti=3 sample was the best.After 120 min UV irradiation,the degradation rate of 0.05 g catalyst to 50 mL 20 mg L-1 Rhodamine B solution was 96.73%.更多还原