TY - JOUR
T1 - Liquid–liquid extraction of neodymium ions from aqueous solutions of NdCl3 by phosphonium-based ionic liquids
AU - Panigrahi, Mrutyunjay
AU - Grabda, Mariusz
AU - Kozak, Dmytro
AU - Dorai, Arunkumar
AU - Shibata, Etsuro
AU - Kawamura, Junichi
AU - Nakamura, Takashi
N1 - Funding Information:
This study was supported by the High Efficiency Rare Elements Extraction Technology Area in the Tohoku Innovative Materials Technology Initiatives for Reconstruction from the Ministry of Education, Culture, Sports, Science, and Technology in Japan .
Publisher Copyright:
© 2016 Elsevier B.V.
PY - 2016/10/17
Y1 - 2016/10/17
N2 - A protocol for the recovery of rare earth elements based on the dissolution of an aqueous solution of a rare earth metal chloride in an ionic liquid (IL) followed by stripping of the dissolved metal ions into an aqueous phase is proposed. The use of ILs is a departure from the traditional strategies employed for extraction. Liquid–liquid extraction of neodymium (Nd) ions from an aqueous solution of NdCl3 with and without hydrochloric acid (HCl) was carried out using phosphonium-based ILs, namely trihexyl(tetradecyl)phosphonium benzoate [T66614][BA] and trihexyl(tetradecyl)phosphonium bis(trifluoromethylsulfonyl)imide [T66614][TFSA]. The extraction was also conducted using a mixture of the aforementioned ILs and toluene. The efficiency of the extraction decreased with increasing concentrations of Nd in the aqueous solution. Furthermore, increasing the concentration of HCl in the aqueous phase decreased the percentage of extracted Nd ions. It indicates that the extraction followed a neutral or ion-pair extraction type of mechanism. Stripping of Nd ions from the metal-loaded organic phase using different acids revealed that HCl and HNO3 were the most effective stripping agents for complete re-extraction of the metal ions. Trihexyl(tetradecyl)phosphonium-based IL with a benzoate counter anion was more effective for Nd extraction than the congener with the bis(trifluoromethylsulfonyl)imide anion.
AB - A protocol for the recovery of rare earth elements based on the dissolution of an aqueous solution of a rare earth metal chloride in an ionic liquid (IL) followed by stripping of the dissolved metal ions into an aqueous phase is proposed. The use of ILs is a departure from the traditional strategies employed for extraction. Liquid–liquid extraction of neodymium (Nd) ions from an aqueous solution of NdCl3 with and without hydrochloric acid (HCl) was carried out using phosphonium-based ILs, namely trihexyl(tetradecyl)phosphonium benzoate [T66614][BA] and trihexyl(tetradecyl)phosphonium bis(trifluoromethylsulfonyl)imide [T66614][TFSA]. The extraction was also conducted using a mixture of the aforementioned ILs and toluene. The efficiency of the extraction decreased with increasing concentrations of Nd in the aqueous solution. Furthermore, increasing the concentration of HCl in the aqueous phase decreased the percentage of extracted Nd ions. It indicates that the extraction followed a neutral or ion-pair extraction type of mechanism. Stripping of Nd ions from the metal-loaded organic phase using different acids revealed that HCl and HNO3 were the most effective stripping agents for complete re-extraction of the metal ions. Trihexyl(tetradecyl)phosphonium-based IL with a benzoate counter anion was more effective for Nd extraction than the congener with the bis(trifluoromethylsulfonyl)imide anion.
KW - IL
KW - Liquid–liquid extraction
KW - NdCl
KW - Stripping
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U2 - 10.1016/j.seppur.2016.07.044
DO - 10.1016/j.seppur.2016.07.044
M3 - Article
AN - SCOPUS:84980320138
SN - 1383-5866
VL - 171
SP - 263
EP - 269
JO - Separation and Purification Technology
JF - Separation and Purification Technology
ER -