It is a big challenge to design advanced adsorbents that have high adsorption capacity and excellent selectivity to efficiently remove organic dyes from complex environmental systems. Herein, by utilizing the adhesion property of polydopamine (PDA) and its crosslinking reaction with polyethyleneimine (PEI), a novel core/shell magnetic MWCNTs/Fe₃O₄@(PDA + PEI) nano-hybrid that carries superior adsorption performance of dyes was constructed through facile polydopamine tailored graft polymerization. In such hierarchical structure, the inner shell of Fe₃O₄ nanoparticles and outer shell of (PDA + PEI) contributed to the abundant active adsorption sites, large specific surface area (126 m²/g) and high saturation magnetization value (10.91 emu/g). As a result, the prepared adsorbent exhibited highly selective adsorption performance toward multiple anionic dyes, including MB, CR, and MO with maximum adsorption capacity of 1449, 1006, and 935 mg/g at 298.15 K, respectively. It was found that the main adsorption mechanism was attributed to the hydrogen bonding and electrostatic interaction. The kinetics data fitted well with the pseudo-second-order model, and both the Langmuir and Freundlich isotherm models presented well fit to the isotherm data. The investigation of thermodynamic study indicated that the adsorption of anionic dyes onto core/shell magnetic MWCNTs/Fe₃O₄@(PDA + PEI) nano-hybrid was spontaneous and endothermic. More importantly, the adsorbent presented excellent regeneration property after multiple adsorption-desorption cycles and prominent stability in harsh environments, especially in the alkaline condition. Therefore, these results revealed the promising applications of hierarchical MWCNTs/Fe₃O₄@(PDA + PEI) nano-hybrid in water remediation.

设计具有高吸附能力和出色选择性以从复杂环境系统中有效去除有机染料的高级吸附剂是一个巨大的挑战。在此，通过利用聚多巴胺（PDA）的粘附性及其与聚乙烯亚胺（PEI）的交联反应，新型核/壳磁性MWCNTs / Fe ₃ O ₄ @（PDA + PEI）纳米杂化体具有优异的染料吸附性能。通过容易的聚多巴胺量身定制的接枝聚合反应构建了聚氯乙烯。在这种分层结构中，Fe ₃ O ₄纳米颗粒的内壳和（PDA + PEI）的外壳有助于形成丰富的活性吸附位点，较大的比表面积（126 m ^2）。/ g）和高饱和磁化强度值（10.91 emu / g）。结果，制得的吸附剂对包括MB，CR和MO​​的多种阴离子染料表现出高选择性的吸附性能，在298.15K下的最大吸附容量分别为1449、1006和935mg / g。发现主要的吸附机理归因于氢键和静电相互作用。动力学数据与拟二阶模型非常吻合，Langmuir和Freundlich等温线模型均与等温线数据非常吻合。热力学研究表明，阴离子染料在核/壳磁性MWCNTs / Fe ₃ O ₄上的吸附@（PDA + PEI）纳米杂化物是自发吸热的。更重要的是，该吸附剂在多次吸附-解吸循环后表现出优异的再生性能，并且在恶劣的环境下，尤其是在碱性条件下具有显着的稳定性。因此，这些结果揭示了分级MWCNTs / Fe ₃ O ₄ @（PDA + PEI）纳米杂化物在水修复中的应用前景。