Extraction of Copper(II) Ions from Aqueous Solutions with a Methimazole-Based Ionic Liquid

Abstract

The recently synthesized ionic liquid (IL) 2-butylthiolonium bis(trifluoromethanesulfonyl)amide, [mimSBu][NTf(2)], has been used for the extraction of copper(II) from aqueous solution. The pH of the aqueous phase decreases upon addition of [mimSBu](+), which is attributed to partial release of the hydrogen attached to the N(3) nitrogen atom of the imidazolium ring. The presence of sparingly soluble water in [mimSBu][NTf(2)] also is required in solvent extraction studies to promote the incorporation of Cu(II) into the [mimSBu][NTf(2)] ionic liquid phase. The labile copper(II) system formed by interacting with both the water and the IL cation component has been characterized by cyclic voltammetry as well as UV-vis, Raman, and (1)H, (13)C, and (15)N NMR spectroscopies. The extraction process does not require the addition of a complexing agent or pH control of the aqueous phase. [mimSBu][NTf(2)] can be recovered from the labile copper-water-IL interacting system by washing with a strong acid. High selectivity of copper(II) extraction is achieved relative to that of other divalent cobalt(II), iron(II), and nickel(II) transition-metal cations. The course of microextraction of Cu(2+) from aqueous media into the [mimSBu][NTf(2)] IL phase was monitored in situ by cyclic voltammetry using a well-defined process in which specific interaction with copper is believed to switch from the ionic liquid cation component, [mimSBu], to the [NTf(2)] anion during the course of electrochemical reduction from Cu(II) to Cu(I). The microextraction-voltammetry technique provides a fast and convenient method to determine whether an IL is able to extract electroactive metal ions from an aqueous solution.

Modulating the Solubilities of Ionic Liquid Components in Aqueous–Ionic Liquid Biphasic Systems: A Q‐NMR Investigation

“…In particular, in the field of metal extraction/separation/recycling by liquid/liquid processes, hydrophobic ILs of the type [C n C m im][Tf 2 N] (1-alkyl, 3-alkyl-imidazolium bis(trifluoromethylsulfonyl)imide) have already proved to be tremendously efficient media for a large variety of metals, [9] from Li + to Pu 4 + , [10,11] including d-elementATT="tptxpt=0mm tptxt=5mm tptxb=1.4mm"s [1,2,[11][12][13] and lanthanoids. [14][15][16][17][18][19] The huge potential that ILs present for extraction processes results from the complex extraction mechanisms, which are strongly dependent not only on the nature of the IL but also on the aqueous phase composition, [20] most often based on nitric or hydrochloAqueous-ionic liquid (A-IL) biphasic systems have been examined in terms of deuterated water, acid, and IL cation and anion mutual solubilities in the upper (water-rich, in mole fraction) and lower phase of aqueous/IL biphasic systems at ambient temperature.…”

Extraction behavior of copper(II) ion with a hydrophobic amino-functionalized ionic liquid

“…This means that the determined value is in good agreement with the certified value. Recently, several works have reported the use of different extraction methods including liquid-liquid microextraction (LLME) [23], in situ solvent formation microextraction (ISFME) [24], homogeneous liquid-liquid extraction (HLLE) [25], cloud point extraction (CPE) [26][27][28] and solid phase extraction (SPE) [29,30] for the extraction of Cu 2+ from various samples. Table 1 summarizes the comparison of various methods for the extraction of Cu 2+ .…”

“…It is should be noted that although two recently published articles [23,24] have reported the extraction of Cu 2+ with ionic liquids, the extraction efficiency of Cu 2+ has not been reported. 6 ] was synthesized and purified according to the procedure described in literature [20][21][22].…”

Supported liquid membranes technologies in metals removal from liquid effluents

“…Some properties, such as the thermal stability and miscibility, mainly depend on the anion, while others, such as the viscosity, surface tension and density, depend on the length of the alkyl chain in the cation and/or shape or symmetry [17] . These characteristics make these reagents suitable for a broad spectrum of uses such as catalytic reactions, organic synthesis, polymer chemistry, fungicides and electrochemical applications [18][19][20][21][22] ; recently, they had been proposed as extractants in solvent extraction and ionic exchange technologies, in order to extract metals from metal-bearing wastewaters [23][24][25][26] .…”