Department of Chemistry and Physics, Grand View University, Des Moines, IA 50316, USA; Department of Civil, Construction, and Environmental Engineering, Iowa State University, Ames, IA 50011, USA.
Department of Civil, Construction, and Environmental Engineering, Iowa State University, Ames, IA 50011, USA.
Int J Biol Macromol. 2024 May;267(Pt 1):131449. doi: 10.1016/j.ijbiomac.2024.131449. Epub 2024 Apr 8.
The depleting supply of natural sources of rare earth elements (REE) is a concern to many nations as demand for advanced technology is becoming vital for national security. In this communication, the recovery of dysprosium(III) from aqueous systems was exemplified by a modified phosphorylated chitosan (PCs/MB) prepared by the C-Mannich reaction of phosphorylated chitosan, glutaraldehyde, and 4-hydroxycoumarin in ethanolic solution. Batch adsorption studies achieved a maximum adsorption capacity (q) of 34 mg/g at 25 °C and pH = 5.4 for 2 h. Fourier Transform-Infrared Spectroscopy, elemental mapping, and quantitative analyses revealed ion-exchange mechanism with C6-phosphate and a synergistic complexation with the amino group between two hexose units of the chitosan chain confirming the correlation provided by the pseudo-second order kinetics (R = 0.9996), extrapolated mean free energy of adsorption (E) of 12.9 kJ/mol from the corrected Dubinin-Radushkevich isotherm, and the extrapolated enthalpy of adsorption (ΔH) of -42.4 kJ/mol from the linearized Van't Hoff plot. Competitive adsorption with iron(II), cerium(III), and neodymium(III) demonstrated preferential removal of dysprosium(III) and complete exclusion of iron(II), which illustrates potential application in the separation of REE from electronic wastes.
由于对先进技术的需求对国家安全至关重要，许多国家都对稀土元素 (REE) 的天然资源供应减少感到担忧。在本通讯中，通过 C-Mannich 反应将磷酸化壳聚糖、戊二醛和 4-羟基香豆素在乙醇溶液中反应，制备了改性磷酸化壳聚糖 (PCs/MB)，从水溶液中回收镝 (III) 为例。在 25°C 和 pH=5.4 下，吸附 2 小时，吸附量 (q) 达到最大 34mg/g。傅里叶变换红外光谱、元素映射和定量分析表明，离子交换机制为 C6-磷酸，壳聚糖链上两个六糖单元之间的氨基协同络合，证实了由拟二级动力学（R=0.9996）提供的相关性，从修正的 Dubinin-Radushkevich 等温线推断出吸附的平均自由能 (E) 为 12.9 kJ/mol，从线性 Van't Hoff 图推断出吸附焓 (ΔH) 为 -42.4 kJ/mol。与铁 (II)、铈 (III) 和钕 (III) 的竞争吸附表明，镝 (III) 优先被去除，而铁 (II) 则被完全排除，这表明其在从电子废物中分离 REE 方面具有潜在应用。
