有机硅烷改性钛柱撑蒙脱石的紫外吸收性质研究

Titanium-pillared montmorillonite has a number of excellent performance, especially good photocatalytic activity, which is widely used in the decontamination of environmental pollutants. But no researcher explores the inhibition of the photoactivity of titanium-pillared montmorillonite, only using the absorptivity of ultraviolet light (UV) for ultraviolet screening. Meanwhile, the relevant studies have overlooked the influences of the crystallochemical characteristics of the montmorillonite. Studies have shown that the organosilane modification can introduce various functional groups to the host structure, changing the properties of the modified samples, but the process is significantly influenced by the surface structure of the host. Therefore, this research attempts to modify titanium-pillared montmorillonite with organosilanes and investigate the relation between the modification and the crystallochemical characteristics of the montmorillonite, expecting to obtain the modified montmorillonite with good UV absorptivity and low photoactivity..Based on the previous work of the applicants, the montmorillonite samples with different cation exchange capacities will be used for composite modification with both tintanium-pillaring and silylation to investigate the effects of the crystallochemical characteristics of montmorillonite and the preparation conditions on the structure and property. And the UV absorptivities and photoactivities of the modified samples will be evaluated..This research will provide not only the important experimental evidences for the composite modification of the montmorillonite, but also a great significance to the comprehensive utilization of the rich montmorillonite resources in China.

钛柱撑蒙脱石具有众多优异的性质，特别是良好的光催化活性，被广泛应用于环境污染物的无害化处理。但目前未见有研究者探索抑制钛柱撑蒙脱石的光活性，仅利用其紫外吸收性质，用于屏蔽紫外光。同时，目前的相关研究大多忽视了蒙脱石主体结构晶体化学特性的影响。研究表明，硅烷化改性可以将多种基团引入主体结构，从而根据需要改变产物性质，但主体物质的表面结构对改性有重要影响。因此，本项目尝试对钛柱撑蒙脱石进行硅烷化改性，探讨改性与蒙脱石晶体化学特性之间的关系，以期望得到具有良好紫外吸收性和较低光活性的改性蒙脱石。.本项目拟在已有的工作基础上，选择不同阳离子交换容量的蒙脱石进行钛柱撑和硅烷化复合改性，探讨蒙脱石的晶体化学特性和制备条件对产物结构与性质的影响；并对改性产物的紫外吸收性质和光活性进行评价。.本项研究不仅为蒙脱石矿物的复合改性提供重要实验依据，而且对我国丰富的蒙脱石资源的综合利用具有重要意义。

钛柱撑蒙脱石具有良好的光催化性能，被广泛应用于环境污染物的去除与降解。但目前未见有研究者探索抑制钛蒙脱石的光活性，仅利用其对紫外光的吸收，用于屏蔽紫外光。本项目的目标是通过对蒙脱石进行钛柱撑和硅烷化复合改性，用以得到具有良好紫外吸收性能的改性蒙脱石。项目收集了来自山东莱阳、福建泉港、内蒙赤峰、新疆哈密、美国怀俄明、浙江安吉的7种蒙脱石样品，通过多种表征手段考察其杂质矿物、结晶度、热稳定性、有机物含量、比表面积和阳离子交换容量，选定内蒙赤峰蒙脱石作为改性原料。钛柱撑实验中，通过考察钛前驱体对柱撑产物层间距的影响，选定钛酸四异丙酯作为改性剂。并进一步探讨了反应温度、水含量和煅烧温度对钛柱撑产物的影响，发现较高的温度虽然有利于获得较大的层间距，但也会加速氢氧化钛沉淀的产生，不利于柱撑；水含量也有类似的影响；煅烧温度在500℃左右比较合适。硅烷改性过程考虑了溶剂、硅烷可水解基团数目与电性、以及不同煅烧温度对改性过程的影响。发现较低的溶剂极性有利于硅烷的负载，可水解基团数目对硅烷负载的影响较小，阳离子型的硅烷更容易负载于钛柱撑蒙脱石上，以及600℃以下的预煅烧温度不会对硅烷的负载产生太大的影响。通过测定最终复合改性样品的紫外-可见光谱和对染料橙黄II的吸附性能，证实钛柱撑和硅烷改性能有效地增强蒙脱石的紫外吸收能力和对阴离子型染料的吸附能力。