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Journal Articles

Extraction properties of trivalent rare earth ions from nitric acid using a triamide-amine extractant

Uchino, Seiko*; Narita, Hirokazu*; Kita, Keisuke*; Suzuki, Hideya*; Matsumura, Tatsuro; Naganawa, Hirochika*; Sakaguchi, Koichi*; Oto, Keisuke*

Solvent Extraction Research and Development, Japan, 30(1), p.39 - 46, 2023/00

The extraction of trivalent rare earth ions (RE$$^{3+}$$) from HNO$$_{3}$$ solution using a triamide amine, tris(N,N-di-2-ethylhexyl-ethylamide)amine (DEHTAA), was conducted, and the extraction mechanism was estimated from extraction behavior of HNO$$_{3}$$ and RE$$^{3+}$$ and the relationship between atomic number and extraction percentages (E%) for RE$$^{3+}$$. A DEHTAA molecule dominantly formed a DEHTAA HNO$$_{3}$$ at 1.0 M HNO$$_{3}$$ and a DEHTAA(HNO$$_{3}$$)$$_{2}$$ at 6.0 M HNO$$_{3}$$ in the acid-equilibrated organic phase. This would provide the unique dependence of E% for the light RE$$^{3+}$$ on the HNO$$_{3}$$ concentration, in which the E% value had a minimum and maximum at $$sim$$0.5 M and $$sim$$2 M HNO$$_{3}$$, respectively. The results of the slope analyses for the distribution ratios for RE$$^{3+}$$ suggested that the dominant RE$$^{3+}$$ complex was RE(NO$$_{3}$$)$$_{3}$$DEHTAA(DEHTAA HNO$$_{3}$$) at 1.0 M HNO$$_{3}$$. The E% for RE$$^{3+}$$ decreased from La$$^{3+}$$ to Lu$$^{3+}$$ at 1.0 M HNO$$_{3}$$; on the other hand, those increased from La$$^{3+}$$ to Nd$$^{3+}$$ at 0.25 M and from La$$^{3+}$$ to Sm$$^{3+}$$ and 6.0 M HNO$$_{3}$$.

Journal Articles

Solvent extraction of cesium using DtBuDB18C6 into various organic solvents

Sasaki, Yuji; Morita, Keisuke; Kitatsuji, Yoshihiro; Ito, Keisuke*; Yoshizuka, Kazuharu*

Solvent Extraction Research and Development, Japan, 28(2), p.121 - 131, 2021/00

 Times Cited Count:2 Percentile:17.76(Chemistry, Multidisciplinary)

High concentration of Cs is present in high-level radioactive waste. It is well-known that Cs is an alkali element and difficult to extract completely into an organic phase. Crown ether compounds are widely available for Cs extractants; DtBuDB18C6 (di-$$t$$-butyl-dibenzo-18crown6), was used in this study. Organic solvents used for the industrial applications, such as $$n$$-dodecane and 1-octanol, have low solubility concerning the compound; other solvents were employed and tested. In this study, ketone-, ether-, and ester-type solvents showed high solubility for DtBuDB18C6 and DtBuDB18C6, when dissolved in ketones and alcohols, exhibited relatively high Cs distribution ratios ($$D$$(Cs)), closely to 10.

Journal Articles

Preliminary study on separation of Dy and Nd by multi-step extraction using TDdDGA

Sasaki, Yuji; Ban, Yasutoshi; Morita, Keisuke; Matsumiya, Masahiko*; Ono, Ryoma*; Shiroishi, Hidenobu*

Solvent Extraction Research and Development, Japan, 27(1), p.63 - 67, 2020/00

 Times Cited Count:6 Percentile:34.72(Chemistry, Multidisciplinary)

Mutual separation technique of Dy and Nd in Nd magnet is studied. Dy is more valuable than Nd, then Dy might be isolated and reused. Lanthanide elements can be extracted thoroughly by diglycolamide (DGA) extractants, we use this reagent for the recovery and isolation of Dy. Tetradodecyl-DGA (TDdDGA) has relatively high separation factors(SF) between Dy and Nd (SF=17-18) in HNO$$_{3}$$ extraction system, counter-current extraction using TDdDGA was applied for their mutual separation. From the present study, using the condition, four extraction stages, organic phase: 0.1M TDdDGA in n-dodecane, aqueous phase: 0.3M HNO$$_{3}$$, 92% Dy can be recovered with 0.7% co-extraction of Nd.

Journal Articles

Extractions and spectroscopic studies of various metals with Diglycolamide-Type Tridentate Ligands

Sasaki, Yuji; Saeki, Morihisa*; Yoshizuka, Kazuharu*

Solvent Extraction Research and Development, Japan, 26(1), p.21 - 34, 2019/06

 Times Cited Count:6 Percentile:28.43(Chemistry, Multidisciplinary)

Three tridentate extractants and three masking reagents including O, N, and S donors have been developed and their properties are compared and discussed. The extractants are termed as tetraoctyl-diglycolamide (TODGA), methylimino-dioctylacetamide (MIDOA) and tetraoctyl-thiodiglycolamide (TDGA(C8)) and masking agents have the same central frame but with short alkyl chain. The results of the present study indicate that TODGA can extract mainly hard acid metals belonging groups 2-4,13-15 in periodic table, MIDOA can extract soft acid metals and oxyanions (groups 5-10, 16), and TDGA can extract soft acid metals (groups 10-11). Some spectrophotometric studies (UV, IR, and NMR) indicate the stoichiometry and effect of donor atoms for metal-complexation. The Hf values, the heat generation during complex formation, obtained by chemical calculation by DFT theory show the reverse-correlation with their extraction ability.

Journal Articles

Mechanism of palladium(II) adsorption from nitric acid solutions by a styrene-divinylbenzene copolymer functionalized with $$N,N,N$$-trimethylglycine

Suzuki, Tomoya*; Narita, Hirokazu*; Ogata, Takeshi*; Suzuki, Hideya; Matsumura, Tatsuro; Kobayashi, Toru; Shiwaku, Hideaki; Yaita, Tsuyoshi

Solvent Extraction Research and Development, Japan, 26(1), p.11 - 19, 2019/06

 Times Cited Count:3 Percentile:14.98(Chemistry, Multidisciplinary)

The ability of AMP03, a styrene-divinylbenzene copolymer functionalized with $$N,N,N$$-trimethylglycine moieties, to adsorb Pd(II) from HNO$$_{3}$$ solutions was investigated to elucidate the affinity of $$N,N,N$$-trimethylglycine for Pd(II). In the present study, we investigated the mechanism of Pd(II) adsorption by AMP03 by means of adsorption experiments, Fourier Transform Infrared (FT-IR) spectroscopy, and Extended X-ray Absorption Fine Structure (EXAFS) spectroscopy.

Journal Articles

Synergistic extraction equilibrium of lanthanide(III) Ions with benzoylacetone and a neutral ligand in an ionic liquid

Hatakeyama, Mizuki*; Nishiyama, Yoshio*; Nagatani, Hirohisa*; Okamura, Hiroyuki; Imura, Hisanori*

Solvent Extraction Research and Development, Japan, 25(2), p.79 - 89, 2018/00

 Times Cited Count:12 Percentile:44.41(Chemistry, Multidisciplinary)

The synergistic extraction of trivalent lanthanide ions (Ln(III)) with benzoylacetone (Hba) and trioctyphosphine oxide (TOPO) in an ionic liquid (IL), 1-butyl-3-methyl-imidazolium bis(trifluoromethanesulfonyl)imide ([Bmim][Tf$$_{2}$$N]), has been investigated. The extractability of Ln(III) with Hba was significantly enhanced in the presence of TOPO. The composition and extraction constants of the extracted species for each Ln(III) were determined by 3-dimensional equilibrium analysis. It was found that all Ln(III) were extracted as cationic ternary complexes such as Ln(ba)$$_{2}$$(TOPO)$$_{2}$$$$^{+}$$ or Ln(ba)(TOPO)$$_{4}$$$$^{2+}$$ with Hba and TOPO. Furthermore, the formation constants of the cationic ternary complexes in the IL indicate that Lu(ba)(TOPO)$$_{4}$$$$^{2+}$$ is the most stable complex in the IL.

Journal Articles

Extraction and separation of Se, Zr, Pd, and Cs including long-lived radionuclides

Sasaki, Yuji; Morita, Keisuke; Suzuki, Shinichi; Shiwaku, Hideaki; Ito, Keisuke; Takahashi, Yuya*; Kaneko, Masaaki*

Solvent Extraction Research and Development, Japan, 24(2), p.113 - 122, 2017/06

The solvent extraction of Se, Zr, Pd, and Cs from nitric acid into 1-octanol (OC) and dodecane has been performed. These elements include long-lived radionuclides in spent nuclear fuels, so a simple separation method is indispensable for the development of the treatment of high-level liquid radioactive waste. It was found that Se can be extracted using phenylenediamine, Zr can be extracted using tetraoctyl diglycolamide and di-2-ethylhexyl phosphoric acid, and Pd can be extracted using (methylimino)bis(dioctylacetamide) and hexaoctylnitrilotriacetamide. These elements can be recovered in over 90% yield by these extractants from nitric acid into OC. A distribution ratio of Cs of greater than 1 can be obtained using di-t-butyldibenzo-18-crown-6. It is clear that 90% recovery of Cs can be achieved using an extraction solvent with ten times the volume of the aqueous phase.

Journal Articles

A Comprehensive extraction study using a mono-alkylated diglycolamic acid extractant; Comparison between a secondary amide group and a tertiary amide group

Sugita, Tsuyoshi; Fujiwara, Iori*; Okamura, Hiroyuki; Oshima, Tatsuya*; Baba, Yoshinari*; Naganawa, Hirochika; Shimojo, Kojiro

Solvent Extraction Research and Development, Japan, 24(2), p.61 - 69, 2017/05

We investigated an influence of amide group in diglycolamic acid-type extractants on extraction property of metal ions. The extraction characteristics of $$N$$-dodecyldiglycolamic acid (C$$_{12}$$DGAA), with a secondary amide group, for 56 metal ions have been investigated, and compared with those of $$N,N$$-dioctyldiglycolamic acid (DODGAA) with a tertiary amide group. Compared with DODGAA, C$$_{12}$$DGAA has a poor extraction performance and separation ability for rare-earth metal ions, except for Sc(III). However, C$$_{12}$$DGAA tended to provide better extraction for relatively small-sized metal ions than DODGAA. In addition, it was found that C$$_{12}$$DGAA enables the selective removal of Hg(II) from aqueous solutions containing various divalent metal ions.

Journal Articles

Extraction behavior of rare-earth elements using a mono-alkylated diglycolamic acid extractant

Shimojo, Kojiro; Fujiwara, Iori*; Fujisawa, Kiyoshi*; Okamura, Hiroyuki; Sugita, Tsuyoshi; Oshima, Tatsuya*; Baba, Yoshinari*; Naganawa, Hirochika

Solvent Extraction Research and Development, Japan, 23(2), p.151 - 159, 2016/05

Liquid-liquid extraction of rare-earth (RE) cations has been investigated using $$N$$-dodecyldiglycolamic acid (C$$_{12}$$DGAA) with a secondary amide group, and compared with that using $$N,N$$-dioctyldiglycolamic acid (DODGAA) with a tertiary amide group. C$$_{12}$$DGAA enables quantitative transfer of all RE cations from moderately acidic solution, while being selective toward the heavier RE cations, and performs better than typical carboxylic-acid-type extractants. However, C$$_{12}$$DGAA provides low extraction performance and separation ability for RE cations compared with DODGAA because of the weaker basicity of the amide oxygen. Slope analysis demonstrated that RE$$^{3+}$$ transfer with C$$_{12}$$DGAA proceeded through a proton-exchange reaction, forming a 1:3 complex, RE(C$$_{12}$$DGAA)$$_{3}$$. Structural characterization by X-ray diffraction revealed that three $$N$$-butyldiglycolamic acid (C$$_{4}$$DGAA) molecules coordinated to the La$$^{3+}$$ central ion in a tridentate fashion and the La$$^{3+}$$ primary coordination sphere consisted of three oxygen atoms from the amide group, three oxygen atoms from the ether group, and three oxygen atoms from the carboxy group.

Journal Articles

Masking effects for Mo, Re, Pd and Ru by S and N-donor reagents through MIDOA and NTAamide extraction

Sasaki, Yuji; Morita, Keisuke; Shimazaki, Shoma*; Tsubata, Yasuhiro; Ozawa, Masaki*

Solvent Extraction Research and Development, Japan, 23(2), p.161 - 174, 2016/05

We examined the masking effects of 16 water-miscible reagents, on the extraction of Mo, Re, Ru, and Pd. The extractants, methylimino-dioctylacetamide (MIDOA) and hexaoctyl-nitrilotriacetamide (NTAamide(C8)), show significantly high distribution ratios for these metals, were employed in this study. Masking effects were observed as a decrease of distribution ratio with an increase of masking agent concentration in these extraction systems. The results showed that Pd and Ru can be masked by similar reagents including N- or S- donor atoms, which suppressed the extraction into the organic phase. In contrast, distribution ratio of Mo was only slightly masked by the above mentioned reagents. The masking of Mo was achieved using complexing agents having a central N(CH$$_{2}$$C(P)=O)$$_{2}$$ framework that is important for this purpose. A masking agent for Re was not found in this study.

Journal Articles

Studies on the extraction of soft acid metal species using MIDOA and analogous compounds

Sasaki, Yuji; Saeki, Morihisa; Sugo, Yumi; Ikeda, Yasuhisa*; Kawasaki, Takeshi*; Suzuki, Tomoya*; Ohashi, Akira*

Solvent Extraction Research and Development, Japan, 22(1), p.37 - 45, 2015/05

 Times Cited Count:13 Percentile:43.82(Chemistry, Multidisciplinary)

An extractant, methylimino-bis-${it N,N'}$-dioctylacetamide (MIDOA), was used for the extraction of soft acid metals. It was found that MIDOA can extract not only Cr(VI), Mo(VI), W(VI), Tc(VII) and Re(VII), whose metals can form the oxonium anions due to their high oxidation states, but also other metal cations, like Nb(V), Ta(V) and Pd(II). Analogous compounds, imino-bis-${it N,N'}$-dioctylacetamide (IDOA) and methylimino-bis-${it N,N'}$-di-2-ethylhexylacetamide (MIDEHA), are synthesized and compared for their extractability. It is clear that these extractants have almost same or lower $$D$$ values than those for MIDOA. In order to examine the effect on extractability with different donor atoms, TODGA (${it N,N,N',N'}$-tetraoctyl-diglycolamide) and TDGA (${it N,N,N',N'}$-tetraoctyl-tyiodiglycolamide) having oxygen and sulfur donor are employed. The comparison of their extractabilities suggests that the trend of Pd and Re extraction is N $$>$$ S $$>$$ O and N $$>$$ O $$>$$ S, respectively.

Journal Articles

Extraction separation of U and Pu by ${it N,N}$-di(2-$$ethylhexyl$$)-2,2-dimethylpropanamide (DEHDMPA) and ${it N,N}$-di(2-$$ethylhexyl$$)butanamide (DEHBA) using mixer-settlers in the presence of degradation products of DEHDMPA and DEHBA

Ban, Yasutoshi; Hotoku, Shinobu; Tsubata, Yasuhiro; Tsutsui, Nao; Matsumura, Tatsuro

Solvent Extraction Research and Development, Japan, 22(1), p.47 - 55, 2015/00

Two sets of continuous counter-current experiments using mixer-setters were performed for evaluating extraction properties of ${it N,N}$-dialkylamides toward U and Pu in the presence of their degradation products. The 1st cycle employed ${it N,N}$-di(2-$$ethylhexyl$$)-2,2-dimethylpropanamide (DEHDMPA) for selective extraction of U(VI), and the 2nd cycle employed ${it N,N}$-di(2-$$ethylhexyl$$)butanamide (DEHDBA) for co-extraction of U(VI) and Pu(IV). Degradation products were added to the organic phase of each cycle. Most of U was effectively extracted by DEHDMPA, and the ratio of U recovered to the U fraction was 99.57%. DEHDMPA barely extracted Pu, and the decontamination factor of U with respect to Pu in the U fraction was 1.1 $$times$$ 10$$^{4}$$. The raffinate of the 1st cycle was used as the feed in the 2nd cycle, and the residual U and almost all Pu were effectively extracted by DEHBA. The degradation products had no detrimental effects on the two-phase separation and the operation of mixer-settlers.

Journal Articles

Continuous liquid-liquid extraction of nickel from simulated electroless nickel plating liquid wastes by using a counter current emulsion flow extractor

Nagano, Tetsushi; Mitamura, Hisayoshi; Yamashita, Yuji; Yanase, Nobuyuki; Suzuki, Hideya; Naganawa, Hirochika

Solvent Extraction Research and Development, Japan, 21(1), p.111 - 117, 2014/00

Simulated electroless nickel plating liquid wastes have been processed by using an emulsion flow extractor of a counter current type with a special focus on influences of dilution of the liquid wastes on the extraction performance. The emulsion flow extractor provides an efficient liquid-liquid extraction by sending solutions without additional stirring or shaking. A solvent used in the present study was Shellsol D70 solution containing LIX84-I as an extractant for nickel and PC88A as an accelerating agent. As a result, it was found that increasing degree of dilution with water resulted in improvement of nickel extractabilities obtained from the emulsion flow experiments with a maximum value of 96% as well as those obtained from batch experiments. Droplet sizes at the lower and the upper sides of emulsion phases, estimated by using high-speed microscope, were 214 $$pm$$ 36 $$mu$$m and 415 $$pm$$ 110 $$mu$$m, respectively.

Journal Articles

Extraction and complexation studies of N-methyl-N-phenyl-2-(1H-benzimidazol-2-yl)pyridine-6-carboxamide with trivalent lanthanide

Akutsu, Kazuhiro*; Suzuki, Shinichi; Kobayashi, Toru; Shiwaku, Hideaki; Okamoto, Yoshihiro; Yaita, Tsuyoshi

Solvent Extraction Research and Development, Japan, 20, p.105 - 114, 2013/00

Journal Articles

Actinides extractability trends for multidentate diamides and phosphine oxides

Sasaki, Yuji; Kitatsuji, Yoshihiro; Sugo, Yumi; Tsubata, Yasuhiro; Kimura, Takaumi; Morita, Yasuji

Solvent Extraction Research and Development, Japan, 19, p.51 - 61, 2012/00

Diamides and phosphine oxides having many kinds of the central frames were synthesized and employed in order to see the behavior of actinides(An)(III), (IV), (V) and (VI). Diamides synthesized here have two, three, or four donor atoms of amidic and etheric oxygen (nitrogen or sulfur, instead) atoms in their central frames, namely the extractants can work as bi-, tri-, and tetradentate modes. Di-phosphine di-oxides ((Bis(diphenylphosphoryl)methane (BDPPM) and bis(diphenylphosphoryl)ethylene (BDPPE)), carbamoylmethylphosphine oxide (octylphenyl-$$N$$,$$N$$-diisobutyl-carbamoylmethylphosphine oxide (CMPO)) are used as the representative actinide extractants. Metal ions of Eu(III), Th(IV), U(VI), Np(V), Pu(IV) and Am(III) in perchloric acid were extracted into nitrobenzene or n-dodecane. Measurement of $$D$$ value at the different extractant concentration gives the information on extraction reaction and their extraction ability. From the present work, the best extractant is BDPPM, due to the strong affinity concerning P=O and form of the bidentate mode with six-membered ring chelation. However, this extractant have low solubility in $$n$$-dodecane. Taking the applicatory properties, e.g., high solubility in $$n$$-dodecane, easy organic synthesis, gasification by combustion and high actinide extractability, into consideration, diglycolamide (DGA) is a promising extractant for radioactive waste treatment.

Journal Articles

Technetium(VII) and rhenium(VII) extraction by a new diamide reagent, 2,2'-(Imino)bis(${it N,N}$-dialkylacetamide) (IDAA)

Sasaki, Yuji; Sugo, Yumi; Saeki, Morihisa; Morita, Yasuji; Ohashi, Akira*

Solvent Extraction Research and Development, Japan, 18, p.69 - 74, 2011/00

The new diamide-type extractant, 2,2-(Imino)bis(${it N,N}$-dialkylacetamide) (IDAA), was developed for Tc recovery. IDAA has a nitrogen donor atom introduced into the center of backbone and shows the tridentate feature by hybrid donor atoms of two carbonyl oxygen and a nitrogen. 2,2-(Methylimino)bis(${it N,N}$-Dioctylacetamide) (MIDOA), 2,2-(Methylimino)bis(${it N,N}$-Didodecylacetamide) (MIDDA), and 2,2-(Imino)bis(${it N,N}$-Didodecylacetamide) (IDDA), the IDAA derivatives, can be dissolved well in n-dodecane, and are readily used in the solvent extraction. In addition to Tc(VII) and Re(VII), Cr(VI), Mo(VI), W(VI), Pd(II) and Pu(IV) can be extracted from nitric acid to n-dodecane by these extractants, therefore IDAA has high extractability with some oxonium anions. The extraction capacity for Re(VII) was measured and more than 37 mM Re(VII) can be extracted by 0.1 M MIDOA.

Journal Articles

Separation of Am, Cm and lanthanides by solvent extraction with hydrophilic and lipophilic organic ligands

Sasaki, Yuji; Kitatsuji, Yoshihiro; Tsubata, Yasuhiro; Sugo, Yumi; Morita, Yasuji

Solvent Extraction Research and Development, Japan, 18, p.93 - 101, 2011/00

The mutual separation of Am, Cm and lanthanides (Ln) by the hydrophilic and lipophilic ligands present in both aqueous and organic phases were studied. The hydrophilic ligands used here are DTPA, malonamide, amicacid, TEDGA and DOODA (C2) and four kinds of extractants, TODGA, TDdDGA, DOODA (C8) and DOODA (C12). DOODA can extract light lanthanides with higher D values into the organic phase, on the other hand DGA shows strong complexing ability with middle and heavy lanthanides in the aqueous phase. The high separation factor, over 1000, of La and Gd can be seen in the extraction using extractant, TDdDGA, and DOODA(C2) as the masking agent. The separation factors of Am/Cm by DOODA(C8, C12) and DGA alone extractants are 1.51-1.94, the values with over 3 can be attained by the proposed conditions in this work.

Journal Articles

Advanced hydrometallurgical separation of actinides and rare metals in nuclear fuel cycle

Ozawa, Masaki; Suzuki, Shinichi; Takeshita, Kenji*

Solvent Extraction Research and Development, Japan, 17, p.19 - 34, 2010/00

A hydrometallurgical separation technologies by novel solvent extraction (SX), ion exchange chromatography (IXC) and electrolytic extraction techniques are reviewed as separation tools for light PGM (Ru, Rh, Pd), Tc and $$f$$-elements in high level liquid wastes of the nuclear fuel cycle. The SX process using N,N-dialkylamide can isolate U(VI) from fission products without Pu(IV) valence control, and extractants with soft-hard hybrid donors (PTA and PDA) and those containing six soft donors (TPEN) show good separation of actinides (III) from lanthanides (III). The catalytic electrolytic extraction (CEE) process utilizing Pd$$_{it adatom}$$ or Rh$$_{it adatom}$$ can effectively separate platinum group metals (PGM), Tc and Re by means of controlled under potential deposition (UPD). Some of the basic work on the hydrometallurgical separation of the elements of interest has been carried out through the strategic Advanced (Adv.-) ORIENT Cycle research in Japan.

Journal Articles

Extraction behavior of indium with TOPO into ionic liquids

Kubota, Fukiko*; Shimobori, Yosuke*; Koyanagi, Yusuke*; Nakashima, Kazunori*; Shimojo, Kojiro; Kamiya, Noriho*; Goto, Masahiro*

Solvent Extraction Research and Development, Japan, 16, p.142 - 146, 2009/00

Journal Articles

Extraction of lanthanide ions with an organophosphorous extractant into ionic liquids

Kubota, Fukiko*; Koyanagi, Yusuke*; Nakashima, Kazunori*; Shimojo, Kojiro; Kamiya, Noriho*; Goto, Masahiro*

Solvent Extraction Research and Development, Japan, 15, p.81 - 87, 2008/00

Extraction of lanthanide ions was carried out with the organophosphorous extractant PC-88A dissolved in an imidazolium-based ionic liquid. PC-88A was soluble in ionic liquids having long-chain alkyl substituents such as octyl and dodecyl groups, [C$$_{8}$$mim] and [C$$_{12}$$mim][TFSI], although short-chain imidazolium ionic liquids could not solubilize the extractant. The extraction equilibrium observed in the ionic liquid system was similar to that in the n-dodecane system, and the extraction behavior could be explained by the same proton exchange mechanism as for the conventional organic solvent system, although the extraction efficiency was not improved. An ionic liquid having shorter alkyl chain [C$$_{8}$$mim] showed a higher extraction ability than [C$$_{12}$$mim][TFSI]. Stripping of the metal ions from the ionic liquids was also examined. Quantitative stripping of the metal ions was achieved by nitric acid in the [C$$_{12}$$mim][TFSI] system.

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