Supercritical fluid extraction of alkali metal ions using crown ethers with perfluorocarboxylic acid from aqueous solution
Supercritical fluid extraction of alkali metal ions using crown ethers with perfluorocarboxylic acid from aqueous solution
复制标题
使用冠醚和全氟羧酸从水溶液中超临界流体萃取碱金属离子
DOI：
10.1039/a808654k
复制
发表时间：
1999
期刊：
影响因子：
--
通讯作者：
H. Inomata
中科院分区：
文献类型：
--
作者：
S. Mochizuki;N. Wada;R. Smith;H. Inomata
在40 °C、8.0- 18.0MPa条件下，研究了冠醚[18-冠-6（18 C6），15-冠-5（15 C5）]对水溶液（K+，Na+：1.7 × 10-4 moldm-3）中碱金属离子的萃取。用~（18）C_6测定钾离子的回收率为1-2%，与压力无关。值得注意的是，在添加剂十五氟正辛酸（PFOA）的存在下，回收率增加到40-60%，这可能是因为PFOA具有亲CO2的氟烷基链，并且容易产生金属-配体络合物的抗衡离子。就钠而言，即使使用PFOA，回收率也很低，这可能与18 C6的空腔尺寸有关。具有较小空腔尺寸的15-冠-5配体将钠回收率提高至20- 40%。这些结果表明，碱金属可以用scCO 2和冠醚配体萃取，并且进一步表明，金属的回收率可以通过添加可以提供亲CO2抗衡离子的物质而大大提高。
The extraction of alkali metal ions from aqueous solution (K+, Na+ : 1.7 × 10–4 mol dm–3) with supercritical CO2 (scCO2) and crown ethers [18-crown-6 (18C6), 15-crown-5 (15C5)] as ligand was investigated at 40 °C and 8.0–18.0 MPa. The recovery for potassium ion was 1–2% with 18C6 and was independent of pressure. Remarkably, the recovery increased to 40–60% in the presence of the additive pentadecafluoro-n-octanoic acid (PFOA), which is probably because PFOA has CO2-philic fluoroalkyl chains, and easily generates counter ions for the metal–ligand complex. In the case of sodium, the recovery was found to be low even with PFOA, which may be related to the cavity size of 18C6. The 15-crown-5 ligand, having the smaller cavity size increased sodium recovery up to 20–40%. These results show that alkali metals can be extracted with scCO2 and crown ether ligands and further that the recovery of the metals can be greatly increased by adding a substance that can supply a CO2-philic counter ion.