Abstract：
Rare earth elements with unique magnetic properties and optical properties, known as the \'industrial vitamin\', has a very high commercial value. As a secondary resource of rare earth elements, low-concentration solution includes mixed rare earth ions, which need to realize efficient separation and recovery urgently. High speed countercurrent chromatography is suitable for the separation and purification of rare earth element ions due to its advantages of large loading, good tolerance to samples, and simple pretreatment. In this study, a carbon dots assisted high speed countercurrent chromatography method was designed and established, the carbon dots were applied to the mobile phase of high speed countercurrent chromatography for the first time. The low concentration of REEs solution was enriched, and the effective separation of La (III), Ce (III), Gd (III) and Er (III) was successfully achieved. The complete separation of La (III), Ce (III), Gd (III) and Er (III) was achieved with a solvent system of 0.05 mol L-1 P507 (PE), 0.05 mol L-1 HNO3, and 0.1 mol L-1 CDs2 carbon dots (1:1:0.01, v/v/v), the upper phase as stationary phase, the lower phase as mobile phase. Density functional theory result showed that the binding energy of REEs (III)-CDs2 was larger than that of REEs (III)-P507, so the affinity of CDs2 to REEs (III) was stronger than that of P507. Therefore, with the addition of CDs2, the ability of mobile phase to elute REEs from the stationary phase was enhanced, and the separation effect was improved.
摘要：
稀土元素具有独特的磁性和光学性质,被称为“工业维生素”，具有很高的商业价值。作为稀土元素的二次资源,低浓度溶液包括混合稀土离子，迫切需要实现高效的分离和回收。高速逆流色谱因其负载量大的优点,适用于稀土元素离子的分离纯化,对样品有良好的耐受性，和简单的预处理。在这项研究中,设计并建立了一种碳点辅助高速逆流色谱法,首次将碳点应用于高速逆流色谱的流动相。低浓度的稀土元素溶液富集，以及La(III)的有效分离，Ce(III),成功实现了Gd(III)和Er(III)。完全分离La(III)，Ce(III),Gd（III）和Er（III）是用0.05molL-1P507（PE）的溶剂系统实现的，0.05molL-1HNO3和0.1molL-1CDs2碳点（1：1：0.01，v/v/v），上相作为固定相，较低的相作为流动相。密度泛函理论结果表明，REE（III）-CDs2的结合能大于REE（III）-P507，因此CDs2对REE（III）的亲和力强于P507。因此,随着CDs2的加入，流动相从固定相洗脱稀土元素的能力得到增强，并提高了分离效果。
