基于天然特性的高岭石表面光催化功能修饰及调控机制研究

Functionalization is the trend of the clay mineral refinement processing. The prerequisite to realize the high value application of minerals with the most competitive power is purposeful functionalized based on their natural characteristics. In this project, on the basis of natural characteristics of kaolinite such as morphology diversity and surface charge adjustable, we has realized one-step photocatalytic functional modification for kaolinite surface and performance control taking Sn/Ti composite oxide as a function body. The shell/core structure photocatalytic materials have been obtained and used for organic wastewater treatment. The influence mechanisms of natural characteristics on the structure and coating state of function body were investigated. The correlation between the change of surface microstructure that attributed to the natural characteristics of kaolinite and photocatalytic property of composites was established, then, the properties regulation of photocatalytic materials can be achieved through using natural characteristics of minerals. The project not only provided ideas for efficient low-cost preparation and performance control of photocatalytic materials, but also provided a theoretical basis for goal-oriented functionalized of kaolinite that centered on high-value applications. Besides, the nano-catalytic material was immobilized on the surface of minerals, which was useful for recycling, also provided a new "green" method for treatment of organic wastewater. The work showed important significance for the development of clay minerals' natural advantages, upgrade the competitiveness of industry and solve the problem of water pollution in our country.

功能化是粘土矿物精细化加工发展的趋势，利用天然特性进行有目的的功能化是实现矿物最具竞争力高值化应用的前提条件。本项目基于高岭石天然形貌多样和表面荷电性质可调等特性，以Sn/Ti复合氧化物为功能体，一步法实现高岭石表面光催化功能修饰及性能调控，将获得的壳/核结构光催化材料用于有机废水处理，考察高岭石天然特性对功能体结构和负载状态的影响机制，建立由高岭石天然特性引申出的光催化材料表面微结构差异与性能之间的关系，达到利用矿物天然特性调控材料性能的目的。本项目的实施有望为光催化材料的高效低成本制备及性能调控提供思路，为高岭石目标导向功能化的高值应用提供理论基础，同时纳米催化材料固定在矿物表面，利于回收，为处理有机废水提供了新的"绿色"方法，对发挥我国粘土矿物天然优势、提高行业竞争力和解决水污染问题都有着重要意义。

非金属矿开发利用程度是衡量一个国家工业化水平发展的重要标志，赋予黏土矿物特殊功能是传统加工技术升级到精细化加工的永恒主题，依据矿物天然特性有目的地功能化是提升非金属矿开发利用水平的关键。.本项目通过研究五种典型软质高岭石特性，建立了高岭石结构有序度、热稳定性、形貌及表面性质之间的联系；提出了高岭石具有片、板、棒、管、卷的多形貌特征；基于其形貌多样和表面荷电性质，采用化学共沉淀法，开发了一步法合成棒/片/管状、分散性好、壳/核结构稳定的SnO2/TiO2/高岭石光催化材料方法，功能体具有SnO2与TiO2两相，TiO2为锐钛矿型，有效避免了SnO2对TiO2导晶作用下的金红石化；明确了水解pH和温度是影响SnO2/TiO2在高岭石表面负载状态的关键；获得了SnO2/TiO2体系的不同粒子形态，并分析了该复合结构及形态带来的表面化学结构差异；建立了高岭石表面功能体化学结构、负载状态与催化性能之间的关系；探讨了Sn/Ti负载层与高岭石表面形成的Si-O-Ti(Sn)和Al-O-Ti(Sn)化学键；系统研究了高岭石形貌对功能体负载状态、结构、性能的影响；以降解亚甲基蓝评价催化性能，发现以片状高岭石作为载体最有利于SnO2/TiO2性能发挥，同条件下降解率大于99%；研究了SnO2/TiO2/高岭石形成过程中不同阶段表面元素成分及化合态转变规律；提出了高岭石基包覆型催化材料性能优化的负载模式。.高岭石天然形貌可影响SnO2/TiO2分散形态和尺寸大小，实现对负载颗粒状态的调控，使材料呈现不同的性能，这验证了项目计划中提出的基于高岭石天然特性调控材料性能的假设，即利用高岭石形貌可实现性能的宏观控制。项目实现了光催化材料的低成本制备及性能调控，研究了矿物在材料合成、结构控制、性能调控中的作用，明确了矿物功能化的意义，对矿物基功能材料基体选择具有一定参考价值，不仅为功能材料的发展提供思路，同时也丰富了以材料为导向的非金属矿物精细化加工基本理论和方法。