Effect of composition and ageing of chloride solutions on extraction of Rh(III) and Ru(III) with phosphonium ionic liquids Cyphos IL 101 and IL 104

ABSTRACT

Rhodium(III) and ruthenium(III) were extracted from chloride solutions with phosphonium ionic liquids trihexyl(tetradecyl)phosphonium chloride or trihexyl(tetradecyl)phosphonium bis(2,4,4-trimethylpentyl)phosphinate in toluene. Influence of HCl and NaCl presence in the feed and IL concentration in the organic phase were determined. Rh(III) transport appeared to be inefficient, while over 70% of Ru(III) was extracted from 3 M HCl. Ru(III) extraction was affected by the feed acidity and the type of extractant used. The spectra of the extracts indicated some changes in the structure of Rh(III) and Ru(III) complexes in the organic phase. Also, ageing of feed solutions on the extraction of Ru(III) and Rh(III) was studied.     

Piperazine Functionalized Resins for Au(III), Pt(IV), and Pd(II) Sorption

The result of synthesis of anion exchangers bearing piperazine functionalities is presented in this paper. A series of new ion exchange resins was synthesized by modification of VBC/DVB copolymer with 1(2-aminoethyl)piperazine (resin 1P), 1-amino-4-methylpiperazine (resin 2P), and 1-methylpiperazine (resin 3P). Adsorption studies of gold, platinum, and palladium were conducted with batch and dynamic method from multicomponent solutions containing AuCl₄^?, PtCl₆^2?, and PdCl₄^2? in the concentration range 10 mg/dm³ to 919 mg/dm³. The resins revealed excellent sorption ability towards these metals. The greatest total sorption capacities were determined as 331 mg/g Au for 2P resin, 405 mg/g Pt for 3P resin, and 150 mg/g Pd for 1P resin. The examined 3P resin showed the best total sorption capacity 796 mg/g. Affinity studies were also conducted. The examined resin 1P revealed the greatest affinity to platinum and palladium (lgK 4.5-5) whereas resin 2P revealed the best affinity to gold where lgK were ca. 4.9.     

Solvent extraction of Eu3+ with 4-oxaheptanediamide into ionic liquid system

ABSTRACT

Liquid–liquid extraction of Eu³⁺ from aqueous solution with 4-oxaheptanediamides (OHAs) as extractant into room temperature ionic liquids (RTILs) of 1-alkyl-3-methylimidazolium hexafluorophosphate (C_nmim⁺PF₆^–, n = 4, 6 and 8) was investigated. The strong affinity of OHAs to Eu³⁺ was observed in the present C_nmim⁺PF₆^– system. The extraction was assumed to proceed by cation-exchange mechanism and formed a 4:1 complex of the OHA extractants and Eu³⁺ in C₄mim⁺PF₆^– system. The preferable composition of extracted species was presumed to be Eu(OHA)₄(H₂O)₄(PF₆)₃ by ESI-MS.     

Separation of scandium(III) from lanthanides(III) with room temperature ionic liquid based extraction containing Cyanex 925

The separation of Sc(III) from Y(III), La(III) and Yb(III) in [C₈mim][PF₆] containing Cyanex 925 has been investigated, and is reported in this paper. A cation exchange mechanism of Sc(III) in [C₈mim][PF₆] and Cyanex 925 is proposed by study of the influence of anionic and cationic species on the extraction. The coefficient of the equilibrium equation of Sc(III) was confirmed by slope analysis of log D_Sc vs log [Cyanex 925], and the loading capacity also confirmed the stoichiometry of Cyanex 925 to Sc(III) was close to 3:1. Infrared data for Cyanex 925 saturated with Sc(III) in [C₈mim][PF₆] indicated strong interaction between P?O of Cyanex 925 and Sc(III). In addition, the relationship between log D_Sc and temperature showed that temperature had little influence on the extraction process, and the resulting thermodynamic parameters indicated that an exothermic process was involved. Copyright © 2007 Society of Chemical Industry     

Physical and electrochemical properties of room-temperature dicyanamide ionic liquids based on quaternary phosphonium cations

The physicochemical and electrochemical properties of room temperature ionic liquids based on quaternary phosphonium cations together with a dicyanamide anion are presented in this report. The most dicyanamide-based phosphonium ionic liquids prepared were hydrophilic, except ionic liquids containing a long alkyl chain in the phosohonium cation. It was found that asymmetric phosphonium cations gave low-melting salts in combination with a dicyanamide anion. The dicyanamide-based phosphonium ionic liquids exhibited relatively low viscosities and high conductivities when compared to those of the corresponding ammonium ionic liquids. Particularly, the ionic liquids containing a methoxy group in the phosphonium cations indicated very low viscosities. Comparatively good electrochemical stability of the dicyanamide-based phosphonium ionic liquids was confirmed by voltammetric measurements. The thermogravimetric analysis suggested that the dicyanamide-based phosphonium ionic liquids showed higher thermal stability than those of the corresponding ammonium ionic liquids, indicating an improving effect of the phosphonium cations on the thermal stability.     

离子液体液液萃取分离正辛烷/邻二甲苯

将直馏石脑油分离为脂肪烃和芳烃有助于实现石脑油资源的优化利用,溶剂萃取是芳烃/脂肪烃分离的重要途径,萃取剂的设计与优选对萃取过程至关重要。实验探究了多种离子液体对正辛烷/邻二甲苯混合物萃取分离的效果,以萃取选择性、分配系数和萃取性能指数作为评价指标优选出1-丁基-2,3-二甲基咪唑四氯化铁([Bm₂im][FeCl₄])萃取剂。对于中低浓度芳烃体系(<33%),在30℃、溶剂质量比为4时,邻二甲苯萃取选择性在45以上,分配系数在0.38~0.40,萃取性能指数在18以上,单次萃取脱芳率可达60%以上。相比传统的环丁砜萃取剂,[Bm₂im][FeCl₄]萃取剂可以使体系具有更大的两相区,易于正辛烷/邻二甲苯的分离。利用量子化学软件探究[Bm₂im][FeCl₄]与正辛烷/邻二甲苯的弱相互作用,并计算其结合能,解释离子液体高选择性萃取邻二甲苯的原因。     

Highly selective solvent extraction of Zn(II) and Cr(III) with trioctylmethylammonium chloride ionic liquid

This study investigates the recovery of Zn(II) and Cr(III) from aqueous solutions based on solvent extraction with trioctylmethylammonium chloride [TOMA⁺][Cl-], commercialy named Aliquat 336. Single metal solutions and binary mixtures of both metals were considered. The effect of relevant operating conditions such as pH, contact time, initial concentration, O/A phase volumetric ratio, and temperature were evaluated. Additionally, loading capacity and stripping studies were performed. Results showed that [TOMA⁺][Cl^?] is an effective extracting agent for Zn(II), reaching maximum removal capacity at pH 1.8 and demonstrating fast extraction kinetics. Extraction efficiencies above 99% were achieved at 0.5, 0.75, and 1.00 O/A volumetric phase ratios for 0.1 g/L initial Zn(II) concentration. At 1 g/L and 10 g/L concentration, for the same O/A ratios, approximately 88% of the initial Zn(II) was extracted. In contrast, it was found that negligible amounts of Cr(III) were transferred to the [TOMA⁺][Cl^?] phase at the 1-5 pH range. Selectivity studies showed that Zn(II) removal is boosted in the presence of Cr(III), although no Cr(III) is extracted. [TOMA⁺][Cl^?] exhibited a high Zn(II) storage capacity, since after 25 loading cycles with 1 g/L, the loading capacity reached approximately 13.5 g/L, and after five loading cycles with 5 g/L, the capacity reached 19.4 g/L. Stripping tests revealed that NaOH is an efficient agent for the removal of Zn(II) from the ionic liquids, reaching 98.5% removal after two cycles, whereas HNO₃ is not a suitable agent, reaching less than 40% removal after three cycles. [TOMA⁺][Cl^?] revealed high potential for separating Zn(II) from Cr(III).     

离子液体促进溶剂萃取油砂沥青

传统水洗法和溶剂萃取法萃取油砂沥青时,存在沥青中含有沙土和残沙中含有油等缺点。为解决上述缺点,本文采用不同比例的乙酸甲酯/正庚烷复合溶剂萃取油砂沥青,研究了离子液体（1-丁基-3-甲基咪唑四氟硼酸盐,[Emim]BF4）对该溶剂萃取体系的萃取率和分离洁净程度的影响。采用红外光谱仪和扫描电镜对萃取后的残沙和沥青的洁净程度进行了定性分析,并结合元素分析仪和电感耦合等离子体发射光谱仪获得萃取后残沙和沥青的洁净程度的定量结果。实验结果表明：当复合溶剂体积比为2∶3时,[Emim]BF4促使沥青回收率达到最大值94.20%,比单纯复合溶剂萃取体系的最大萃取率高7.92%;通过上述测试方法的定性和定量分析,证明了[Emim]BF4能有效解决沥青夹带沙土和残沙中含油的问题。     

The extraction of platinum from Pt(II) chloride solution by a quaternary ammonium compound

The fundamental aspects of the extraction and stripping of platinum (II) from its chloride solution by Aliquat 336 diluted with toluene have been studied. The extraction and stripping was at 99.5 and 97.6% equilibrium within 30 s and 20 min respectively. The percentage extraction increased slightly with decreasing hydrochloric acid concentration. In 0.1 mol dm^?3 hydrochloric acid, 1.0 volume percent Aliquat 336 in toluene could load 9.8 mmol dm^?3 of platinum (II). The percentage stripping of platinum (II) from Pt(II)-load organic solvent increased with increasing sodium bisulphite concentration. The enthalpy changes of extraction and of stripping were 12.8 and 114.9 kJ mol^?1 respectively. Both of the reactions were endothermic.     

Electrochemical behavior of ruthenium (III), rhodium (III) and palladium (II) in 1-butyl-3-methylimidazolium chloride ionic liquid

Electrochemical behavior of ruthenium (III), rhodium (III) and palladium (II) in 1-butyl-3-methylimidazolium chloride (bmimCl) and their ternary and binary solutions in bmimCl was studied at various working electrodes at 373 K by cyclic voltammetry and chronoamperometry. Ruthenium (III) chloride forms a stable solution with bmimCl and the cyclic voltammogram of ruthenium (III) in bmimCl recorded at glassy carbon electrode consisted of several redox waves due to the complex nature of ruthenium to exist in several oxidation states. Electrolysis of ruthenium (III) chloride in bmimCl at the cathodic limit of bmimCl (−1.8 V (vs. Pd)) did not result in ruthenium metal deposition. However, it was deposited from bmimPF₆ and bmimNTf₂ room temperature ionic liquids at −0.8 V (vs. Pd). The electrochemical behavior of ruthenium (III) in bmimCl in the presence of palladium (II) and rhodium (III) was studied by cyclic voltammetry. The presence of palladium (II) in bmimCl favors underpotential deposition of ruthenium metal. The nuclear loop at −0.5 V (vs. Pd) was observed in all solutions when palladium (II) co-existed with other two metal ions. Nucleation and growth of the metal on glassy carbon working electrode was investigated by chronoamperometry. The growth and decay of chronocurrents has been found to follow the instantaneous nucleation model with three-dimensional growth of nuclei.     

Solvent extraction and separation of light lanthanoids with mixtures of two chelating extractants: Benzene vs. ionic liquid

Solvent extraction of lanthanoids (La-Gd) with mixtures of a chelating extractants (HL), either 4-(4-fluorobenzoyl)-3-methyl-1-phenyl-pyrazol-5-one(HPMFBP) or 3-methyl-4-(4-methylbenzoyl)-1-phenyl-pyrazol-5-one (HPMMBP) and 1-(2-thienyl)-4,4,4-trifluoro-1,3-butanedione (thenoyltrifluoroacetone, HTTA) has been studied in benzene. The composition of the extracted species was established as LnL₃·HL with the two para-substituted 4-aroyl-3-methyl-1-phenyl-pyrazol-5-ones. It was found that, in the presence of a thenoyltrifluoroacetone, the lanthanoids were extracted as LnL₃·HTTA. The separation factors between adjacent metals were evaluated. The extraction of Eu(III) ions was investigated by use of ionic liquid, 1-methyl-1,3-butylimidazolium-bis(trifluoromethanesulfonyl)imide instead of benzene in order to make comparison without looking at the mechanism aspects.     

Extraction of Pr(III), Nd(III), and Dy(III) from HTFSA Aqueous Solution by TODGA/Phosphonium-Based Ionic Liquids

The extraction behavior of rare earth (RE) elements using N,N,N′,N′-tetraoctyl diglycolamide (TODGA) in an ionic liquid (IL) system was investigated by slope analyses. Metallic salts of Pr(III), Nd(III), and Dy(III) with bis(trifluoromethylsulfonyl)amide (TFSA) were synthesized and studied for their extraction mechanism. The selected concentration of TODGA was diluted with triethylpentylphosphonium bis(trifluoromethylsulfonyl)amide ([P₂₂₂₅][TFSA]) to prepare an extracting phase for the slope analyses. The stoichiometry of RE(III) was determined in order to estimate the extracted species. Furthermore, the complexation state of the extracted species was evaluated by spectroscopic analyses, including Fourier-transform infrared (FT-IR) spectroscopy, Raman spectroscopy, and ultraviolet–visible (UV–Vis) spectroscopy. The FT-IR and Raman spectra were estimated using density functional theory (DFT) calculations. Thorough analysis of the FT-IR spectrum was carried out in order to assign the TODGA group that mainly coordinated the metal ion. The solvation of the [TFSA]^? anion in the coordination sphere of [Nd(TODGA)_(2–3)]³⁺ was investigated by Raman spectroscopic analysis. The coordination ability of TODGA was investigated from the peak shift of the hypersensitive transition (⁴I_9/2→²G_7/2) in UV–Vis spectroscopic measurements. From electrochemical analysis, the extracted [Nd(TODGA)₃]³⁺ complex in [P₂₂₂₅][TFSA] was found to be reduced as per the following reaction: [Nd(TODGA)₃]³⁺ + 3e^? → Nd(0) + 3[TODGA] at ?3.0 V, and the diffusion coefficient of [Nd(TODGA)₃]³⁺ was calculated to be 1.6 × 10^?11 m² s^?1 at 373 K. The direct electrodeposition of the extracted [Nd(TODGA)₃]³⁺ in [P₂₂₂₅][TFSA] at 373 K allowed us to conclude that the middle layer of Nd electrodeposits was the metallic state, while a part of the top surface was the oxidation state by XPS analysis.     

Extraction and separation of Pt(IV)/Rh(III) from acidic chloride solutions using Aliquat 336

Extraction and separation of Pt(IV)/Rh(III) from chloride solutions using Aliquat 336 (Quaternary ammonium salt made by the methylation of mixed tri octyl/decyl amine) diluted in kerosene as an extractant/synergist alone and mixed with organophosphorous extractants as synergists/extractants were carried out from an aqueous feed containing 0.0005 mol L⁻¹ Pt(IV)/Rh(III).Variation of hydrochloric acid concentration of aqueous phase from 0.005 to 10.0 mol L⁻¹ increased the percentage extraction of platinum up to 5.0 mol L⁻¹ there after it decreases. Whereas in the case of rhodium, from 0.005 to 1.0 mol L⁻¹ acid range the percentage extraction was decreased from 1.0 to 10.0 mol L⁻¹ acid range is favorable for extraction. Platinum(IV)/rhodium(III) separation factor of 279.2 was obtained at 1.0 mol L⁻¹ HCl concentration with 0.005 mol L⁻¹ Aliquat 336 and separation factor of 612.3 was obtained at 3.0 mol L⁻¹ HCl concentration with 0.01 mol L⁻¹ Aliquat 336. The present study optimized the various experimental parameters like phase contact time, effect of extractant, salts, temperature, loading capacity of extractant, stripping studies with various mineral acids/bases, recycling and reusing capacity of extractant up to ten cycles.     

Extraction of U(VI), Th(IV), and Lanthanides(III) from Nitric Acid Solutions with CMPO-Functionalized Ionic Liquid in Molecular Diluents

The extraction of microquantities of U(VI), Th(IV), and lanthanides(III) from nitric acid solutions with CMPO-functionalized ionic liquid 1-[3[[(diphenylphosphinyl)acetyl]amino]propyl]-3-tetradecyl-1H-imidazol-3-ium hexafluorophosphate, CMPO-FIL(I) in molecular organic diluents has been studied. The effect of HNO₃ concentration in the aqueous phase and that of extractant concentration in the organic phase on the extraction of metal ions is considered. The stoichiometry of the extracted complexes was determined. CMPO-FIL(I) demonstrates greater extraction ability towards Ln(III) than its neutral CMPO analog, diphenylphosphorylacetic acid N-nonylamide. This inner synergistic effect increases with a decreasing organic diluent polarity. The partition of CMPO-FIL(I) between the equilibrium organic and aqueous phases is the dominant factor governing the extractability of Ln(III) ions in the extraction system.     

Solvent extraction separation of titanium(IV), vanadium(V) and iron(III) from simulated waste chloride liquors of titanium minerals processing industry by the trialkylphosphine oxide Cyanex 923

The solvent extraction of magnesium(II), aluminium(III), titanium(IV), vanadium(V), chromium(III), manganese(II) and iron(III) from hydrochloric acid solutions has been investigated using the trialkylphosphine oxide Cyanex 923 (TRPO) in kerosene as extractant. The results demonstrate that titanium(IV), vanadium(V) and iron(III) are extracted into kerosene as TiOCl₂·2TRPO, VO₂Cl·TRPO and HFeCl₄·2TRPO, respectively. On the other hand magnesium(II), aluminium(III), chromium(III) and manganese(II) are not extracted with TRPO from hydrochloric acid solutions (1.0–4.0 mol dm^?3) under the experimental conditions. IR spectral studies of the extracted complexes were further used to clarify the nature of the extracted complexes. The effect of the diluent on the extraction of titanium(IV), vanadium(V) and iron(III) has been studied and correlated with the dielectric constant. The loading capacity of the TRPO system has been evaluated and the potential for the separation and recovery of titanium(IV), vanadium(V) and iron(III) from simulated waste chloride liquors of the titanium minerals processing industry has been assessed. Copyright © 2004 Society of Chemical Industry     

Hg(II) removal from HCl solutions using a tetraalkylphosphonium ionic liquid impregnated onto Amberlite XAD‐7

Extractant impregnated resins (EIRs) were prepared by impregnation of Amberlite XAD‐7 with tetraalkylphosphonium chloride ionic liquid (IL). The EIRs were tested for the sorption of Hg(II) in HCl solutions. Mercury is bound on the EIR through an ion exchange mechanism involving chloroanionic species and the IL. The effect of HCl concentration and IL content is studied and the sorption isotherms are obtained in 1 M HCl solutions: the sorption capacity linearly increases with IL loading up to 100 mg Hg L^?1. A little fraction of the IL immobilized on the resin (about 40 mg IL g^?1) is tightly bound to the polymer limiting its reactivity with metal ions. The uptake kinetics are mainly controlled by intraparticle diffusion. At high IL loading the kinetics are slowed down, while the temperature has a limited impact. Nitric acid can be used for desorbing mercury and recycling the EIR for at least five cycles. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 41086.