Zhang Sheli, Yan Yuerong, Zhou Qiang, Fan Yunchang
School of Science and Technology, Jiaozuo Teachers College, Jiaozuo 454000, China.
College of Chemistry and Chemical Engineering, Henan Polytechnic University, Jiaozuo 454003, China.
Molecules. 2024 Aug 24;29(17):4007. doi: 10.3390/molecules29174007.
The recovery of scandium (Sc) from highly acidic industrial effluents is currently hindered by the use of large quantities of flammable and toxic organic solvents. This study developed an extraction system using ionic liquids (ILs) and phenylphosphinic acid (PPAH) as diluents and an extractant, respectively, to selectively recover Sc from the aqueous phase. The effect of IL chemical structure, aqueous pH and temperature on the extraction of Sc was systematically investigated and the findings revealed that ILs with longer alkyl side chains had reduced Sc extraction ability due to the presence of continuous nonpolar domains formed by the self-aggregation of the IL alkyl side chain. The IL/PPAH system maintained high extraction ability toward Sc across a wide temperature range (288 K to 318 K) and the extraction efficiency of Sc could be improved significantly by increasing the aqueous pH. The extraction process involved proton exchange, resulting in the formation of a metal-ligand complex (Sc(PPA)).
目前，从高酸性工业废水中回收钪（Sc）受到大量易燃有毒有机溶剂使用的阻碍。本研究开发了一种萃取体系，分别使用离子液体（ILs）和苯基次膦酸（PPAH）作为稀释剂和萃取剂，以从水相中选择性回收Sc。系统研究了离子液体化学结构、水相pH值和温度对Sc萃取的影响，结果表明，由于离子液体烷基侧链自聚集形成连续非极性域，具有较长烷基侧链的离子液体对Sc的萃取能力降低。离子液体/苯基次膦酸体系在较宽温度范围（288 K至318 K）内对Sc保持较高萃取能力，通过提高水相pH值可显著提高Sc的萃取效率。萃取过程涉及质子交换，导致形成金属-配体络合物（Sc(PPA)）。
