摘要 
     通常在含有有机和无机污染物的水中检测到抗生素和重金属的共存。在这项工作中，使用可重复使用的温敏性壳聚糖基絮凝剂（CS-g-PNNPAM）对水中四环素（TC）和Cu（II）进行分离和连续回收。TC和Cu（II）水中协同去除率高达 90％以上。采用响应面法评估目标水温（T1），原液温度（T2）和絮凝剂用量对絮凝性能的影响。为了优化絮凝效果，通过数学分析给出了根据交互效应调整T2和剂量T1的操作策略。通过实验研究（絮体尺寸监测，X射线光电子能谱和紫外光谱）和理论计算（密度泛函理论和理论计算）研究了CS-g-PNNPAM，TC和Cu（II）之间的絮凝机理以及界面相互作用。 Cu（II）与TC的配位作用和絮凝剂对絮凝的促进作用：TC-絮凝剂在不同温度下的可切换相互作用（H键和疏水缔合）是影响操作策略的关键因素。当这些相互作用逐步减弱时，使用某些溶液从絮凝物中依次回收TC和Cu（II）。同时，絮凝体中的絮凝剂经过再生处理可重复使用，絮凝效率高。

     Coexistence of antibiotics and heavy metals is typically detected in water containing both organic and inorganic contaminants. In this work, a flocculation method using a reusable thermoresponsive chitosan-based flocculant (CS-g-PNNPAM) was applied for separation and sequential recovery of tetracycline (TC) and Cu(II) from water. High synergistic removal rates of both TC and Cu(II) from water (>90%) were reached. Interactive effects among targeted water temperature (T1), stock solution temperature (T2), and flocculant dosage on flocculation performance were assessed using response surface methodology. To optimize flocculation, operation strategies of adjusting T2 and dosage according to T1 based on the interactive effects were given through mathematical analyses. The flocculation mechanism as well as interfacial interactions among CS-g-PNNPAM, TC, and Cu(II) were studied through experimental investigations (floc size monitoring, X-ray photoelectron spectroscopy, and UV spectra) and theoretical calculations (density functional theory and molecular dynamics simulations). Coordination of Cu(II) with TC and the flocculant promoted flocculation; switchable interactions (H bonds and hydrophobic association) of the TC–flocculant at different temperatures were key factors affecting operation strategies. When these interactions were weakened step by step, TC and Cu(II) were sequentially recovered from flocs using certain solutions. Meanwhile, the flocculant in flocs was regenerated and found reusable with high flocculation efficiency.
 
https://pubs.acs.org/doi/abs/10.1021/acsami.7b00828