基于络合位与电荷分布理论的水体有机物混凝去除机理定量表征与计算

Enhanced coagulation is recommended as the best availabe technolgy (BAT) to remove aquatic organic matter (AOM) and is used widely in drinking water treatment. The acknowledge of coagualtion is still very limited because it is comprised by a lot of complicate phyichemical processes, there is no relaiable methods and tools to characterize the interaction between coagulant and AOM at very low concentration level in the condition of coagulation. The mechaneism of coagulation can only be attributed qualitively to complex, neutraliztion, and adsorption by now. It prohabits the improvement of coagulation technology..Based on our recent improvement in the approaches of characterizing water chemistry processes at realistic concentration of AOM in enviroment, this project will characterize the ligands and charge distribution in AOM and coagulant Al hydrolyzed products, the interactions between Al hydrolyzed products and AOM,e.g. Al(ion)-AOM and Al(floc)-AOM interactions.In combination with the understanding of the characteristics and distribution of Al hydrolyzed products, a mathamatical model based on Ligand and Charge Distribution (LCD) theory will be provided to discrible the complicate interaction among Al(ion)-AOM-Al(floc). This LCD model will ellustrate the contributions of mechanisms, complex, neutralization and adsorption to AOM removel by coagulation quantifiedly. The results in this project will do great favor to the studies in the fields of high effectiveness coagulant development, water treatment processes optimaization, automatic controling and dosing.

混凝是去除水体中有机物(AOM)的最佳可行性技术。混凝包括复杂的物理、化学过程，而且AOM、絮凝剂浓度低，因缺乏有效的表征方法和手段，目前混凝去除AOM机理的认识仍然停留在络合、电中和、吸附等定性描述的水平上，制约了混凝技术的发展。.本项目利用项目组建立的UV-Vis光谱与石英微晶体天平相结合的微量AOM水化学过程表征新方法，定量表征与计算AOM和絮凝剂铝盐水解絮体的络合位与荷电特性，以及AOM与离子态、絮体态絮凝剂分别发生的络合、电中和、吸附等微界面作用过程；结合絮凝剂混凝过程中水解产物形态分布特征，建立基于络合位与电荷分布理论（LCD）的Al离子—AOM—絮体三元体系作用过程计算模型，定量阐述混凝去除AOM的络合、电中和、吸附作用机理。对指导高效絮凝剂开发、水处理工艺优化与自动控制具有重要意义。

本项目执行期为2016年01月至2019年12月，为期四年。在项目执行期内，项目组按项目计划执行，基本实现项目预期目标。主要包括：（1）系统调查我国饮用水水源中有机物特性及其与Al/Fe等金属离子络合关联。证明了有机物的特性，尤其是络合特性是混凝过程中Al形态分配的重要因素。（2）建立了有机物分离提纯设备，对南水北调等重点水源中进行浓缩提纯，并进行了AOM精细结构表征，构建了AOM分子模型。（3）建立了光谱法与石英微晶体天平相结合的液-液、液-固界面表征方法，实现了Al-AOM、AOM-颗粒物二元体系定量表征。（4）在完成Al-AOM、AOM-颗粒物二元体系实验基础上，开展Al-AOM-颗粒物三元体系下竞争作用实验。研究了NOM-颗粒物、Al-NOM-颗粒物、背景离子存在条件下Al-NOM-颗粒物等各种情况下物质分配，解析出多元竞争现象和分配规律。（5）将本项目部分研究成果已应用于解决北京市南水北调水源饮用水余铝超标重大工程问题及自然科学基金委“河流多物质相互作用及其通量效应”创新群体项目。.截止2019年底，正式发表论文10篇，其中在本领域顶级期刊Water Research 和 Environ Sci Technol发表论文5篇，另外多篇论文在撰写或已投稿；申请发明专利1项。在该项目支持下，10余名研究生和若干本科生课题研究进展顺利，项目组成员科研能力得到显著提高。