Extraction of metal ion

In separation, ILs are mainly used to extract metal ions with popular ILs [C4QIm][PFJ, [QCiIm][PFg], or other ILs with [PFJ or [TfjN] anions [162-167], ILs have usually hydrophobic character that allows them to extract hydrophobic compounds in biphasic separation. Metal ions tend to stay in the aqueous soluhon being hydrated. Therefore, to remove metal ions from the aqueous phase into the hydrophobic IL, extractants (ligands) are normally needed to form complexes to increase fhe hydrophobicify of fhe mefal. In more details this area will be covered in chapter 10 of fhe book. 

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Extraction of metal ions Extraction processes Extraction resistance Extractive distillation... 

The extraction of metal ions depends on the chelating ability of 8-hydroxyquinoline. Modification of the stmcture can improve its properties, eg, higher solubility in organic solvents (91). The extraction of nickel, cobalt, copper, and zinc from acid sulfates has been accompHshed using 8-hydroxyquinohne in an immiscible solvent (92). In the presence of oximes, halo-substituted 8-hydroxyquinolines have been used to recover copper and zinc from aqueous solutions (93). Dilute solutions of heavy metals such as mercury, ca dmium, copper, lead, and zinc can be purified using quinoline-8-carboxyhc acid adsorbed on various substrates (94). 

Metal Extraction. As with other carboxyhc acids, neodecanoic acid can be used in the solvent extraction of metal ions from aqueous solutions. Recent appHcations include the extraction of zinc from river water for deterrnination by atomic absorption spectrophotometry (105), the coextraction of metals such as nickel, cobalt, and copper with iron (106), and the recovery of copper from ammoniacal leaching solutions (107). 

In the pulp and paper industry, anionic and cationic acrylamide polymers are used as chemical additives or processing aids. The positive effect is achieved due to a fuller retention of the filler (basically kaoline) in the paper pulp, so that the structure of the paper sheet surface layer improves. Copolymers of acrylamide with vi-nylamine not only attach better qualities to the surface layer of.paper, they also add to the tensile properties of paper in the wet state. Paper reinforcement with anionic polymers is due to the formation of complexes between the polymer additive and ions of Cr and Cu incorporated in the paper pulp. The direct effect of acrylamide polymers on strength increases and improved surface properties of paper sheets is accompanied by a fuller extraction of metallic ions (iron and cobalt, in addition to those mentioned above), which improves effluent water quality. 

The nature of the donor atoms in the chelating agent. Ligands which contain donor atoms of the soft-base type form their most stable complexes with the relatively small group of Class B metal ions (i.e. soft acids) and are thus more selective reagents. This is illustrated by the reagent diphenylthiocarbazone (dithizone) used for the solvent extraction of metal ions such as Pd2+, Ag+, Hg2+, Cu2+, Bi3+, Pb2+, and Zn2 +. ... 

Discussion. Because of the specific nature of atomic absorption spectroscopy (AAS) as a measuring technique, non-selective reagents such as ammonium pyrollidine dithiocarbamate (APDC) may be used for the liquid-liquid extraction of metal ions. Complexes formed with APDC are soluble in a number of ketones such as methyl isobutyl ketone which is a recommended solvent for use in atomic absorption and allows a concentration factor of ten times. The experiment described illustrates the use of APDC as a general extracting reagent for heavy metal ions. 

The extraction of metal ions from aqueous sulphate media by alkylamines. R. W. Cattrall and S. J. E. Slater, Coord. Chem. Rev., 1973,11, 227-245 (64). 

Liquid-liquid extractions of metal ions by chelating ligands. E. Uhlig, Coord. Chem. Rev., 1982, 43, 299-312 (38). 

The solvent extraction of metal ions by crown compounds. Y. Takeda, Top. Curr. Chem., 1984,... 

Analytical applications of substituted cinnamohydroxamic acids in spectrophotometry and solvent extraction of metal ions. Y. K. Agrawal and R. K. Jain, Rev. Anal. Chem., 1982, 6,49-64 (71). 

D. Extraction of Metal Ions with Sulphoxides and Sulphones.573... 

Liquid Liquid Extraction of Metal Ions D. F. Peppard... 

Visser AE, Swatloski RP, Reichert WM, Mayton R, Sheff S, Wierzbicki A, Davis JH, Rogers RD (2001) Task-specific ionic liquids for the extraction of metal ions from aqueous solutions. Chem Commun 1 135-136... 

Visser, A.E., Swatloski, R.P., Reichert, W.M. et al. (2001) Task-Specific Ionic Liquids for the Extraction of Metal Ions from Aqueous Solutions. Chemical Communications, 1, 135-136. 

Takeda, Y. The Solvent Extraction of Metal Ions by Grown Compounds. 121, 1-38 (1984). 

The catalytic role of the liquid-liquid interface in the solvent extraction of metal ions described in this chapter and some important remarks on the interfacial phenomena reported in other studies are summarized ... 

The major uses of non-ionizing solvents in chemical analysis are twofold. They may be used simply to provide media for the dissolution and reaction of covalent materials, or they may play a more active part in a chemical process. For example, oxygen-containing organic solvents can be used to effect the solvent extraction of metal ions from acid aqueous solutions the lone pair of electrons possessed by the oxygen atom forming a dative bond with the proton followed by the extraction of the metal ion as an association complex. 

Uses Plasticizer for lacquers, plastics, cellulose esters, and vinyl resins heat-exchange liquid carbonless copy paper systems in aircraft hydraulic fluids solvent extraction of metal ions from solution of reactor products uranium extraction and nuclear fuel reprocessing pigment grinding assistant antifoaming agent solvent for nitrocellulose and cellulose acetate. 

Computational Chemistry in Modeling Solvent Extraction of Metal Ions... 

Peppard, D. F. Liquid-liquid extraction of metal ions. In Advances in Inorganic Chemistry and Radiochemistry, Academic Press New York and London, 1966 Vol. 9, p. 1. 

Cloud point extraction of metal ions. The use of cloud point extraction as a separation technique was first introduced by Watanabe for the extraction of metal ions forming sparingly water soluble complexes [109], Since then, the technique has been applied successfully to the extraction of metal chelates for spectrophotometric, atomic absorption, or flow injection analysis of trace metals in a variety of samples [105-107,110]. Other metal complexes such as AUCI4 or thiocyanato-metal complexes can be extracted directly using nonionic surfactants such as polyoxyethylene... 

Conventional extraction with chemical reaction is used for solutes that are insoluble in the organic phase unless they react with a reagent present in that phase. An example of this is the extraction of metal ions described by Eq. (15.8). In this case, if the organic phase is replaced by a W/O microemulsion containing the reactant, there is usually extraction enhancement due to the solubilization of the metal complex in the microphase. There are two possible ways of forming a W/O microemulsion in the solvent phase ... 

The most commercially important mechanism of all is the kinetics of solute transfer from an aqueous to a reverse micelle phase. The kinetics of extraction of metal ions have not received the same research attention as the extraction capacity of W/O microemulsions. As the mechanism of extraction of metal ions is chemical, the effect of creating a microemulsion in an organic phase that contains the reactant can be measured experimentally. Results indicate that, as in the case of extraction equilibrium, the rate of extraction may increase substantially by the presence of the microemulsion as compared with the conventional system [20,38,44] or decrease it to... 

It has already been shown in Chapter 4 (section 4.2.1) that from the thermodynamic point of view the process described by Eq. (16.2) can be modeled by the sum of its partial processes (extraction steps), irrespective of whether they really proceed or not. That is because Gibbs free energy is the function of state and its total change does not depend on the reaction path. According to the complex formation-partition model [76], one can distinguish two main steps in extraction of metal ions ... 

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