地聚合物体系中水组分的演变规律及重金属废弃物的自解毒机制研究

A large number of untreatable solid wastes contain heavy metals and exert tremendous pressure on the environment. Traditional solidification techniques by cement have a problem of increasing the volume, and also bring negative effect on the energy saving, emission reduction and environment protection. It is the requirement of sustainability development to study eco-cementitious materials which could be disposal of solid wastes containing heavy metals more efficient, realization of system self-detoxification and resource utilization. This study aims to prepare the geoploymer from municipal solid wastes incineration fly ash, chromium slag, and sludge, etc., and to determine the key technical parameters. The reaction procedure of the prepared geopolymer will be researched deeply. In the geopolymeric systems, the existing forms, evolution regulars, and action mechanism of the waters will be focused on using advanced testing techniques and computer simulation technique. The effects, movement and transformation, solidification/stabilization mechanism of heavy metals will be studied. Special agents aimed to self-detoxify and control the system would be investigated. Structure especially microstructure of geopolymers will be tested in multi-scale. Based on molecular dynamics simulation, the quantitative model of the micro-structure of geopolymer will be proposed, and the intrinsic relation between the evolution of water, self-detoxification of heavy metals, and microstructure will be determined. This study will explore a new way for recycling of solid wastes containing heavy metals, provide the referencing basis for application development and ensuring environmental safety of geopolymers, and lay a theoretical and practical foundation for developing the low carbon economy goal and green building materials.

大量难以处置的重金属固体废弃物给生态环境造成了巨大压力，而传统水泥固化技术不仅增容大，且不利于节能减排和环境保护。研究既能高效处置重金属废弃物又能实现体系自解毒及资源化利用的生态胶凝材料是社会可持续发展的迫切需求。本课题拟利用垃圾焚烧飞灰、铬渣、污泥等，确定关键技术参数，研制地聚合物；联合采用现代先进测试技术及计算机模拟技术，从机理上深入研究地聚合物的反应过程，地聚合物体系中水组分的存在形式、演变规律及作用机制；研究重金属的影响机制、迁移及转化规律、固化/稳定化机理、专用药剂研制及体系自解毒与控制机制；多尺度研究地聚合物的内部结构，尤其是体系微结构；基于分子动力学模拟技术，构建地聚合物微结构定量模型，揭示水演变及自解毒重金属与体系微结构的内在关系。本课题将为重金属废弃物资源化开辟新途径，为拓宽地聚合物应用途径及确保其环境安全性提供参考依据，为低碳经济目标和绿色建材发展打下理论和实践基础。

本课题利用粉煤灰、铬泥、垃圾焚烧飞灰研制地聚合物，重点研究了地聚合物体系中水组分演变规律和重金属解毒机制及固化体的抗侵蚀性和安全性。研究表明：地聚合物处置垃圾飞灰和铬泥适宜比例分别为5%和15%。热分析表明，地聚合物体系中（7d）自由水：物理结合水：化学结合水约为9:2:1；低场核磁共振表明，随反应进行浆体中毛细水含量呈下降趋势，而凝胶水则相反；稳定期，毛细水：凝胶水≈1: (2.15~3.64)。重金属对地聚合物影响需综合考虑种类、掺量和赋存形式；XPS和ESEM表明，不同重金属引起电子云密度变化，导致元素结合能变化；重金属固化体中物理包裹、吸附作用和化学键合同时存在，主次视重金属化合物形态而定。固化体毒性浸出浓度远低于上限值，可有效固化/稳定化重金属；化学药剂具有选择性，有机化学药剂较优；分子动力学模拟构建了地聚合物微结构定量模型并应运于高温环境；药剂改性危废基地聚合物具有良好抗酸/碱性侵蚀能力。本课题为地聚合物协同处置含重金属危废及确保其环境安全性提供了参考依据，为低碳经济和绿色建材发展打下理论和实践基础。专著1部；学术论文30篇，其中SCI/EI收录论文21篇；国家发明专利4项，已授权2项，转化1项；国际/内会议特邀报告2次，口头报告5次。