微污染水中典型重金属离子在系列多胺类螯合树脂上的无机盐强化去除原理

The adsorption and separation behavior of heavy metal ions (HMIs) onto series of polyamine chelating resins (PCRs) from micro-polluted aqueous media, with or without the presence of various levels of such common ions as Cl-, NO3-, SO42-,PO43-, NH4+, Na+, Ca2+, Mg2+, Fe3+, Al3+, were comparably explored by carrying out the sole-/binary-/multiple-component static, kinetic and dynamic experiments. Equilibrium capacities, thermodynamic parameters, kinetic and selective characters, were thoroughly calculated to describe the interaction processes. Meanwhile, the impact factor and unit increment were introduced to quantitatively describe the enhancement effect of salt. Moreover, the structure-activity relationship was established based on the solid physical/chemical structure, HMIs characteristics, salt levels, and so on. The structural evolutions of PCRs before/after HMIs-loaded were investigated in virtue of SEM, TEM, FTIR, XPS, etc. Additionally, several models such as DFT, SCM, RSM, were applied to identify the predominant chelating modes and interaction configuration, and thus to qualitatively and quantitatively reveal the enhanced mechanisms behind the selective removal toward HMIs. The simulation study was further developed on the selective removal of coexistent HMIs onto PCAs from real micro-polluted aqueous media, for examining the selectivity order and environmental limitation involving initial concentration and ion strength, for selecting the best ion pairs involving enhancer-ion and enhanced-ion, and for explaining the micro-interface interaction mechanisms as well as the principle of enhanced removal in various saline systems. The project would lead to the theoretical guidance for the optimization of solid physic-chemical structure and real application procedures, especially explore a novel technique for the efficient removal of HMIs from complex micro-polluted aqueous media.

对比研究无盐条件与常见无机（氯、硝酸根、硫酸根、磷酸根、铵、钠、钙、镁、铁、铝）离子胁迫下，微污染水中典型重金属（铅、镉、汞、铜、镍）离子在系列多胺类螯合树脂上的单、双、多组分静态和动态吸附分离行为。利用吸附容量、热力学和动力学常数、选择性系数等定量描述交互作用特性，利用无机盐影响系数、单位增强率等定量描述盐增强效应，并与吸附剂理化结构、重金属离子特征、无机盐胁迫强度等形成构效关联，通过SEM、TEM、FTIR、XPS、ESR等表达重金属负载前后结构演变，利用DFT、SCM、RSM等模拟确定主导螯合方式和空间构型。进一步模拟共存复杂离子在实际微污染水中的选择去除行为，验证优控序列及关键阈值（浓度、强度），筛选最友好离子对（最优增强离子-最易被增强离子），揭示微界面交互作用机制，并在离子水平上定量揭示无机盐强化去除原理，为多胺类螯合树脂优化制备、微污染水中典型重金属离子优先控制提供理论指导。

本课题通过多种方法优化制备了系列苯乙烯系、丙烯酸系多胺螯合树脂、胺基吡啶耐酸耐盐树脂以及壳聚糖基多胺改性水凝胶，并系统研究了其对水体中典型重金属在无机盐胁迫下的增强去除特性。结果表明自合成吸附剂对重金属具有特异的盐促效应，即无机盐的存在可显著提升重金属的吸附速率、吸附量和吸附选择性。重金属与无机盐在在吸附剂表界面的交互影响与材料理化结构、污染物性质及环境因素紧密相关。利用Zeta电位、FT-IR、XPS、DFT计算等分析得出重金属、无机盐阴离子与树脂的结合形式及固液相络合、桥联构型，揭示了阴离子通过压缩双电层增强重金属吸附的内在机理。固定床研究表明通过控制适宜的条件可以实现共存重金属的无机盐强化分离回收，为高盐环境中多种重金属的高效资源化和无害化提供了重要指导。