Abstract A ternary nanocomposite integrating polyethyleneimine (PEI), magnetite (Fe3O4) nanoparticles, and illite/smectite clay nanoflakes (denoted as PEI-MI/S) was prepared via a mechanochemical route in a high-energy density stirred bead mill. The ternary PEI-MI/S nanocomposite was determined by X-ray diffraction, Fourier transform infrared spectroscopy, thermogravimetry, scanning electron microscopy, transmission electron microscopy, vibrating sample magnetometry and X-ray photoelectron spectroscopy, respectively. The results show that ternary PEI-MI/S nanocomposite can be prepared in the presence of intense grinding, which can graft a more amount of PEI rather than that prepared in the absence of grinding. The compressive and shear stresses in intense grinding can disperse Fe3O4 nanoparticles and exfoliate/destruct I/S clay nanoflakes. Also, the mechanochemical effect facilitates the hydrogen bond and electrostatic interaction between PEI and magnetic I/S, and the crosslink reaction between PEI and glutaraldehyde in grinding, resulting in a more grafting amount of PEI. Ternary PEI-MI/S nanocomposite was applied for the removal of hexavalent chromium (Cr(VI)) anions in aqueous solution. The effect of parameters (i.e., pH value, adsorption time, temperature, and initial concentration of Cr(VI) anions) on the adsorption performance was investigated. It is indicated that the adsorption of Cr(VI) anions onto PEI-MI/S nanocomposite be related to the adsorption/reduction process. Ternary magnetic PEI-MI/S nanocomposite with a saturated magnetization (Ms) of 14.7 emu/g facilitates the magnetic separation and reusability. The regenerated ternary PEI-MI/S nanocomposite can maintain 71.43% of initial activity for adsorption of Cr(VI) anions after 6 cycles.

中文翻译：

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三元聚乙烯亚胺改性磁性伊利石/蒙脱石纳米复合材料的机械化学制备去除水溶液中的Cr(VI)

摘要 在高能量密度搅拌珠磨机中通过机械化学途径制备了一种由聚乙烯亚胺 (PEI)、磁铁矿 (Fe3O4) 纳米颗粒和伊利石/蒙脱石粘土纳米薄片（表示为 PEI-MI/S）组成的三元纳米复合材料。三元PEI-MI/S纳米复合材料分别通过X射线衍射、傅里叶变换红外光谱、热重法、扫描电子显微镜、透射电子显微镜、振动样品磁强法和X射线光电子能谱测定。结果表明，三元PEI-MI/S纳米复合材料可以在剧烈研磨的情况下制备，与没有研磨的情况相比，可以接枝更多的PEI。强力研磨中的压应力和剪应力可以分散 Fe3O4 纳米颗粒并剥离/破坏 I/S 粘土纳米薄片。还，机械化学效应促进了PEI与磁性I/S之间的氢键和静电相互作用，以及PEI与戊二醛在研磨中的交联反应，导致PEI的接枝量更多。三元 PEI-MI/S 纳米复合材料用于去除水溶液中的六价铬 (Cr(VI)) 阴离子。研究了参数（即 pH 值、吸附时间、温度和 Cr(VI) 阴离子的初始浓度）对吸附性能的影响。表明 Cr(VI) 阴离子在 PEI-MI/S 纳米复合材料上的吸附与吸附/还原过程有关。饱和磁化强度 (Ms) 为 14.7 emu/g 的三元磁性 PEI-MI/S 纳米复合材料有助于磁分离和可重复使用。再生后的三元 PEI-MI/S 纳米复合材料可以保持 71。