Abstract In this paper, a novel polyamide containing pyrimidine and methine thiophene linkages (poly(pyrimidine-thiophene-amide) (P(P-T-A))) was synthesized. Then, the magnetic calcium alginate nanocomposite containing P(P-T-A) (CA-P(P-T-A)-Ni0.2Zn0.2Fe2.6O4 (NZFO)) was synthesized for studying neodymium (Nd+3), terbium (Tb+3), and dysprosium (Dy+3) ions adsorption in the single ion solutions. The obtained results of X-ray diffraction (XRD), field emission scanning electron microscope (FE-SEM), energy-dispersive X-ray (EDX), nuclear magnetic resonance (NMR), thermogravimetric analysis (TGA), vibrating sample magnetometer (VSM), and Fourier transform infrared (FT-IR) indicated the successful synthesis of the materials. The value of saturation magnetization of the nanocomposite was reported to be 15.28 emu/g, indicating an appropriate magnetic response. Under the optimum conditions, adsorption efficiency for Nd+3, Tb+3, and Dy+3 was 96.73, 94.82, and 97.58 %, respectively. According to the experimental results, it can be stated that the data of REEs adsorption were efficiently fitted by nonlinear pseudo-second-order kinetic model. Adsorption isotherms were also evaluated by fitting with Freundlich and Langmuir isotherm models. A better fit was achieved by Freundlich model in the case of Tb+3 and Dy+3 ions, while Langmuir isotherm fitting reported a better result for Nd+3 adsorption data. Moreover, the changes in Gibbs free energy (ΔG°), enthalpy (ΔH°), and entropy (ΔS°) values presented a feasible and endothermic ions adsorption process onto the nanocomposite that occurred spontaneously under the investigated conditions. The obtained results indicated that the nanocomposite can be considered as a potential adsorbent for the efficient adsorption of the investigated ions.

中文翻译：

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带有聚（嘧啶-噻吩-酰胺）的新型海藻酸钙磁性纳米复合材料作为一种新型绿色合成聚酰胺，用于吸附研究钕、铽和镝稀土离子

摘要 本文合成了一种含有嘧啶和次甲基噻吩键的新型聚酰胺（聚（嘧啶-噻吩-酰胺）（P（PTA）））。然后，合成了含有 P(PTA) (CA-P(PTA)-Ni0.2Zn0.2Fe2.6O4 (NZFO)) 的磁性海藻酸钙纳米复合材料，用于研究钕 (Nd+3)、铽 (Tb+3) 和镝 (Dy+3) 离子在单离子溶液中的吸附。X射线衍射（XRD）、场发射扫描电子显微镜（FE-SEM）、能量色散X射线（EDX）、核磁共振（NMR）、热重分析（TGA）、振动样品磁强计（ VSM）和傅里叶变换红外（FT-IR）表明材料合成成功。据报道，纳米复合材料的饱和磁化强度值为 15.28 emu/g，指示适当的磁响应。在最佳条件下，Nd+3、Tb+3和Dy+3的吸附效率分别为96.73、94.82和97.58%。实验结果表明，稀土元素吸附数据通过非线性拟二级动力学模型进行了有效拟合。吸附等温线也通过拟合 Freundlich 和 Langmuir 等温线模型进行评估。在 Tb+3 和 Dy+3 离子的情况下，Freundlich 模型实现了更好的拟合，而 Langmuir 等温线拟合报告了更好的 Nd+3 吸附数据结果。此外，吉布斯自由能 (ΔG°)、焓 (ΔH°) 和熵 (ΔS°) 值的变化表明，在研究条件下自发发生在纳米复合材料上的吸热离子吸附过程是可行的。