Green and sustainable recovery of high-value natural flavonoids in agricultural wastes could not only improve natural resource utilization, but also could effectively reduce environmental pollution. Recently, great efforts have been made for research on the development of magnetic imprinted composite adsorbent, but the simultaneous promotion of stable selectivity and high adsorption amounts still faces its challenges. Inspired by “Sandwich-like” transport channels with proper steric and specific affinity sites, herein we designed a new kind of surface-imprinted magnetic colloidal nanocrystal clusters (MCNCs) with dual recognition sites (MCNCs@DR-MIPs) via sequential surface imprinted strategy. A two-step sequential surface-initiated atom transfer radical polymerization (SI-ATRP) was employed to construct the double imprinted sites, which can significantly improve the adsorption selectivity and adsorption amounts. In this design, the metal ion Zn(II) and the low pKa boronic acid APBA (1-allylpyridine-3-boronic acid, pKa = 7.4) could effectively tune the appropriate yolk-shell confinement sites, the obtained artificial double imprinted binding sites establishes the promising chemical environment for selective separation. As expected, the adsorption equilibrium experiments exhibited adsorption kinetics (180 min) and the maximum equilibrium binding capacity (34.60 µmol g). In virtue of unique advantages of magnetic separation materials, this novel absorbent exhibited a green and environmentally friendly enrichment process for naringin (NRG). Meanwhile, MCNCs@DR-MIPs showed excellent selectivity (imprinted factor 2.15) and regeneration properties (only decreased by 8.22 % after 7 cycles) for NRG. Additionally, the commercially available NRG could be effectively extracted and concentrated to 94.78 %. This study offers a sustainable effective strategy for flavonoids purification of magnetic separation materials and promotes advance the other natural compounds from agricultural wastes.

中文翻译：

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顺序组装增强了磁性印迹聚合物对柚皮苷的特异性捕获的选择性：协同双位点和印迹效应的组合


绿色、可持续地回收农业废弃物中的高价值天然黄酮类化合物，不仅可以提高自然资源利用率，还可以有效减少环境污染。近年来，人们在磁印迹复合吸附剂的开发方面做出了巨大的努力，但同时提升稳定的选择性和高吸附量仍面临挑战。受具有适当空间和特定亲和位点的“三明治式”传输通道的启发，我们通过顺序表面印迹策略设计了一种具有双识别位点的新型表面印迹磁性胶体纳米晶簇（MCNCs@DR-MIPs） 。采用两步顺序表面引发原子转移自由基聚合（SI-ATRP）构建双印迹位点，可以显着提高吸附选择性和吸附量。在该设计中，金属离子Zn(II)和低pKa硼酸APBA（1-烯丙基吡啶-3-硼酸，pKa = 7.4）可以有效地调节合适的蛋黄壳限制位点，获得人工双印迹结合位点为选择性分离建立了有前景的化学环境。正如预期的那样，吸附平衡实验表现出吸附动力学（180 分钟）和最大平衡结合容量（34.60 µmol g）。这种新型吸附剂凭借磁分离材料的独特优势，展现出绿色环保的柚皮苷（NRG）富集工艺。同时，MCNCs@DR-MIPs 对 NRG 表现出优异的选择性（印记因子 2.15）和再生特性（7 个循环后仅下降 8.22%）。 此外，市售的 NRG 可以有效提取并浓缩至 94.78%。这项研究为磁分离材料的黄酮类化合物纯化提供了一种可持续有效的策略，并促进了农业废物中其他天然化合物的发展。