畜禽生化尾水中典型重金属与抗生素复合污染物在多胺磁性碳球上的共去除机制

The combined pollution of heavy metals (HMs) and antibiotics (ANTs) in livestock secondary effluents brings serious threats to the ecosystem and human health. To address it, this project focuses on the co-removal of HMs and ANTs by polyamine-modified magnetic carbon spheres (N-MCs). Series N-MCs will be prepared by various methods with different carbon and amine precursors. The adsorption behaviors and properties of HMs (Cu, Zn) and ANTs (tetracyclines, sulfonamides, quinolones) onto N-MCs in both sole and binary systems will be systematically investigated. The relationships between the coadsorption properties (adsorption amount, synergistic effect) and the physical-chemical structures of both pollutants and N-MCs will be explored. Moreover, with the characterizations of the aqueous and solid phases, the mutual interactions and coadsorption mechanisms will be illuminated by the determination of preferred adsorbate species and dominant adsorption sites. In addition, the influence of regular inorganic salts, N/P nutritive salts and dissolved organics will be also studied. The research will provide both theoretical and technological supports for adsorbents design and advanced treatment of livestock wastewaters.

针对畜禽生化尾水中重金属与抗生素复合污染物的高效去除难题，本项目拟选取不同的生物质、胺化试剂，通过多种合成路线调控制备系列理化结构的多胺磁性碳球（N-MCs），对比研究不同重金属（铜、锌）和抗生素（四环素类、磺胺类、喹诺酮类）复合污染物在N-MCs上的单、双组分吸附容量、吸附速率及随pH、浓度等因素的变化规律，建立复合污染物、吸附剂的理化结构与共吸附性能（吸附总量、协同效应）间的构效关系和数理模型。借助多种固、液相微观表征手段分析吸附质形态、关键吸附位点等，从分子、离子水平定量揭示复合污染物交互作用和共去除机制，并考察共存常规无机盐、氮磷营养盐和其他溶解性有机物对目标污染物共吸附的影响规律与机制，为N-MCs优化制备、畜禽生化尾水中重金属与抗生素复合污染物共吸附去除技术提供理论指导。

本课题通过多种方法优化制备了系列化多胺修饰的人工高分子基和生物质基碳球，系统考察了其对畜禽生化尾水中残留的典型重金属（铜、锌）和抗生素（磺胺类、头孢类和喹诺酮类）共吸附去除特性。研究表明，多胺碳球对重金属与抗生素在一定浓度、pH范围内具有协同吸附特性。重金属与抗生素的吸附分别基于与胺基的配位和静电/氢键作用，其吸附亲和力分别与固相胺基总量及伯胺量呈正相关。借助滴定、ESI-MS、XPS等表征方法和DFT计算解析了固、液相中复合污染物的存在形态、吸附亲和位点及络合/配位构型，并通过顺序投加实验、相似物比对、过程水质追踪和动态柱饱和等方法揭示了“三元架桥作用”、“静电屏蔽效应”和“络合物增强亲和”等协同共吸附机制。常见共存无机盐促进重金属的吸附，复合体系下无机盐对抗生素吸附的抑制效应降低，腐殖酸对两种目标污染物的去除影响较小。采用盐/碱-酸组合方式基本可以实现吸附剂的完全再生和复合污染物的分质脱附，光催化、过硫酸盐等非均相高级氧化技术可用于对抗生素-盐/碱脱附液中抗生素的降解矿化。该研究为开发适于畜禽生化尾水中重金属与抗生素复合污染一体式深度净化的材料与技术提供了理论指导。