生物质基多功能复合气凝胶的结构调控与高效去除水中多种污染物的研究

This project intends to prepare three-dimension multifunctional nanocomposite aerogel adsorption materials used in sewage water treatment based on biomass substrate. With lignin, gelatin and agarose biomass as raw material, the 3D porous aerogel material could be constructed via the hydrogen bond and covalent bond cross-linking through the abundant reactive groups such as hydroxyl, amino, supplemented biomass substrate. With the prepared biomass aerogel as template, nano hydroxyapatite with designed shape and distribution will be prepared in situ via the wet chemical synthesis. The microstructure and hierarchical morphology of the multifunctional organic-inorganic nanocomposite aerogel adsorption material can be controllable by directional frozen ice template technology and freeze-drying process. The super wetting and intelligent stimuli-responsive performance for the hybrid aerogel will be achieved by surface chemical modification. The efficient removal ability of the nanocomposite aerogel to the various contaminant such as oil, heavy metal ions and organic molecules should be realized. The influence of preparation parameters, directional frozen template technology and freeze-drying process on the microstructure and mechanical property of the prepared aerogel will be investigated systematically. The relationship of the absorption behavior for the contaminant molecules with three-dimensional porous structure and chemical composition of the aerogel will be established. Furthermore, the adsorption mechanism based on thermodynamics will be revealed. This project provides scientists with a new way to synthesize the novel multifunctional nanocomposite aerogel materials. The research work also brings new solutions for the daily grim crisis of water pollution.

本项目从木质素、琼脂糖等生物质基材出发，藉助生物质基材上丰富的羟基、氨基等反应性基团，辅以戊二醛、甲醛等化学交联剂，通过氢键与化学交联的共同作用构筑三维多孔气凝胶基材。再以此为模板，采用湿式化学原位合成形状和体积可控的纳米羟基磷灰石，通过定向冷冻的冰模板技术与冻干工艺实现对复合气凝胶材料微结构的精确调控，构建三维多功能有机-无机纳米复合气凝胶吸附材料，经表面化学修饰赋予其特殊的表面超浸润性和智能响应性，实现对复杂污水中多种污染物，如油类、重金属离子和有机小分子等的高效去除能力。系统研究复合气凝胶的微结构、机械稳定性与智能响应性能，考察气凝胶三维多孔结构与化学组成对污染物分子吸附作用的影响规律与机理。该项目的实施将为多功能纳米复合气凝胶材料的合成与应用提供新的思路。

本项目以不同的生物质材料为基材，制备化学结构和物理结构不同的生物质气凝胶，并将其与功能性聚合物、无机纳米粒子实现有效结合，得到具有良好的机械性能、结构稳定性、特殊功能性的多功能材料，研究其在水处理和能量转换领域的应用特性。探索材料结构设计与功能实现的密切关系，为多功能性生物质气凝胶的设计制备提供可能的途径。以木质素、琼脂糖和聚乙烯醇为原材料，通过简易的制备过程得到可再生的、环境友好的、具有蜂窝状孔结构的生物质基气凝胶。以明胶为原材料制备明胶基复合气凝胶，其中，二氧化钛纳米粒子以共混的方式掺入明胶骨架结构，聚乙烯亚胺通过化学交联剂的作用与明胶相结合，氢键与化学键的协同作用为明胶基复合气凝胶的结构稳定性提供了保障。以明胶基复合气凝胶为研究对象，研究其去除水中有机染料和重金属离子的性能。明胶基复合气凝胶对阳离子染料和阴离子染料都有吸附作用，对亚甲基蓝的吸附容量可达 81.41mg/g，这是由于有机染料分子与气凝胶之间的静电作用力和氢键作用。以机械性能优异、可实现大规模生产的细菌纤维素为原材料通过冷冻干燥技术和逐步浸涂法制备了有机-无机复合气凝胶。所制备的细菌纤维素基复合气凝胶具有三维多孔结构，且氧化银纳米粒子稳定而均匀地分散在孔壁上，赋予其优异的可见光催化降解性能。项目进一步通过对生物质气凝胶的多尺度微结构与性能进行调控，利用生物质基材上丰富的反应性基团，通过湿法化学工艺原位合成纳米羟基磷灰石，得到有机-无机纳米复合型气凝胶材料。再经表面化学修饰赋予其特殊的表面超浸润性和智能响应性，实现对复杂污水中多种污染物，如油类、重金属离子和有机小分子等的高效去除能力。该项目为无机-有机多功能纳米复合气凝胶材料的合成提供了新的途径，也为日趋严峻和水污染问题提供了新的解决方案。