水泥表层固载原位双负载硅基复合纳米材料的可见光空气净化研究

In order to develop the important demand for environmentally friendly functional cement for safe and long-term service, this project plans to construct in-situ and double-loaded SiO2 based composite nanomaterials, which can be chemically stabilized and double-densified with cement-based materials to realize cement-based materials with air purification under visible light and Long-term safe service due to erosion resistance. The three-dimensional configuration of the in-situ double-loaded SiO2 based composites is controlled, and the stable uniform loading problem of the cement photocatalyst is solved by chemical reaction coupling; the TiO2/SiO2/noble metal or metal oxide is used to expand the light absorption range to realize air purification on the surface of cement under natural light conditions; Based on the volcanic ash activity characteristics of SiO2 carrier, the solid coupling with cement is achieved through the reaction of SiO2 with cement hydration products, and the surface quality of cement is improved; The photo-hydrophilic of TiO2 induces the dense of cement surface to achieve the dual synergistic effect of the composite structure on the densification of cement surface, which effectively improves the dielectric resistance of the cement matrix; Controlling the composite structure and studying the kinetics of pollutant diffusion and degradation, and the concentration gradient is to be done to achieve the atmospheric purification function of cement-based materials, which lays a theoretical and technical foundation for the design and development of high-performance environmentally-friendly cement-based materials.

针对开发安全长效服役的环保功能性水泥的重大需求，本项目拟构建原位生长双负载SiO2基复合纳米材料，利用其与水泥基材料具有化学稳固耦合和双重密实化作用，实现水泥基材料的可见光空气净化与抗侵蚀的长期安全服役。调控原位双负载SiO2基复合材料的三维构型，通过化学反应耦合解决水泥光催化剂的稳定均一固载问题；利用TiO2/SiO2/（贵）金属（氧化物），扩展光吸收范围，实现在自然光条件下水泥表层空气净化；基于SiO2载体的火山灰活性特点，通过SiO2与水泥水化产物作用反应实现与水泥的稳固耦合，同时改善水泥表层质量；基于TiO2的光致亲水诱导水泥表层致密化作用，实现该复合结构对水泥表层致密化的双重协同效应，有效提升水泥基体的抗介质传输性能；调控复合材料结构，研究污染物扩散、降解的动力学过程以及浓度梯度，实现水泥基材料的大气净化作用，为高性能的环保水泥基材料的设计开发奠定理论与技术基础。

混凝土表面与人居环境直接接触，量大面广，主要担负结构防护和装饰功能。近年来，面对当前日益严重的环境问题，利用混凝土表层作为载体，研究开发具有环保功能性水泥材料对有效解决环境污染问题具有重要意义。.针对开发安全长效服役的环保功能性水泥的重大需求，本项目构建原位生长双负载SiO2 基复合纳米材料，利用其与水泥基材料具有化学稳固耦合和双重密实化作用，实现水泥基材料的可见光空气净化与抗侵蚀的长期安全服役。调控原位双负载SiO2基复合材料的三维构型，制备了TiO2@SiO2, SiO2@TiO2, SiO2@N-TiO2,SiO2@TiO2/Ag，SiO2@V，Mn-TiO2，SiO2@F,V,Mn-TiO2一系列SiO2基复合材料。通过贵金属、掺杂等改性方式扩展光吸收范围，实现在自然光条件下水泥表层空气净化；利用TiO2/SiO2/（贵）金属（氧化物），基于SiO2载体的火山灰活性特点，通过核磁共振，光电子能谱，扫描电镜及X-射线衍射等表征手段揭示了SiO2基复合材料与水泥基材料的作用机制，说明通过SiO2与水泥水化产物作用反应实现与水泥的稳固耦合。同时改善水泥表层质量，水泥基材料表层结构更加致密，吸水率降低高于17%；水泥基材料表层的光催化效果优异，在可见光激发下，NOx的降解效率高于30%，对染料的降解效率高于70%，同时经过实验室模拟雨淋测试，耦合后光催化没有明显的降低，说明光催化耐久性较好，通过SiO2与光催化材料的构建与三维构型调控，明显提升水泥基表层的光催化效率及耐久性，同时改善水泥基体表层结构，提高基体耐久性。该项目的研究内容为其他功能性水泥基材料制备与性能提升奠定理论与技术基础，同时在水泥基材料在应用于空气净化领域开辟新途径。