Cation exchange separation of metal

J. S. Fritz and B. B. Garralda, Cation exchange separation of metal ions with hydrobromic acid. Anal. Chem. 34,102,1962. 

Ishii, D., Hirose, A., Hibi, K., and Iwasaki, Y., Studies on micro high-performance liquid chromatography. 5. Design of a microscale liquid chromatograph and its application to cation-exchange separation of alkali-metals. Journal of Chromatography 157(Sep), 43-50,1978. 

J. S. Fritz and L. H. Dahmer, Cation exchange separation of molybdenum, tungsten, niobium and tantalum fiom other metals, Anal Chem., 37,1272,1965. 

J. S. Fritz and S. K. Karraker, "Ion Exchange Separation of Metal Cations", Anal. Chem. 32, 957 (i960). 

S. Fritz and J. E. Abbink, Cation exchange separation of vanadium from metal ions. Anal. Chem., 34,1080,1962. 

The applicability of induced pH gradients for separation of metal ions within anion- and cation-exchange columns was verified. 

Ion exchange from organic solvents and mixed organic aqueous solvents offers interesting possibilities for the extraction and separation of metals because of the different nature of the solvation processes in these systems. Only cation solvation is significant in dipolar, aprotic, organic... 

Small and co-workers [6] at Dow Chemical discovered that alkali and alkaline earth metals could be separated and determined analogously to anions with a cation exchange separation and an anion stripper now commonly known as a suppressor. With the latest developments in high efficiency columns and high capacity suppressors, it is possible to determine the common alkali and alkaline earth metals along with ammonia in a single injection run of less than 15min (Fig. 2.1). 

Juang R.-S. and Huang H.-C., Non-dispersive extraction separation of metals using hydrophilic microporous and cation exchange membranes. J. Membr. Sci. 156, 179, 1999. 

Toxic trace elements were isolated from water samples by extraction with di-ethyldithiocarbamate (Table 2.1.2). Following this pre-concentration step the metal ions were adsorbed on a cation-exchange resin using a mixture of tetrahydro-furan-methylglycol-6 M HCl as sorption solution. The succesive elution was treated with 6 M HCl, 1 M HCl and 2 M HNO3 for fractional separation. In another application hexane-isopropanol-HCl mixture was used as the adsorption medium An analytical scheme which provides quantitative results, is described for ion-exchange separation of fifteen major, minor and trace elements in silicates For concentration and separation of copper, chromium, lead and iron an ion-exchanger in phosphate or OH -form was used in various combinations ... 

Kawazu, K. Comparison of efficiency of cation-exchange resins in the chromatographic separation of metal ions with aqueous aceton-hydrochloric acid solutions. J. Chromatogr. 137, 381 (1977)... 

Ion Exchange Experiments. As described by Rao, et al. (70), ion exchange experiments were performed using columns of 1.2 cm inner diameter, with 5.7 cm of the column filled with Dowex 50 x 4, 100-200 mesh cationic exchange resin. This technique is designed to provide rapid separation of metal bound strongly to the polyelectrolyte from other metals (i.e., imcomplexed or labile metal complexes) in the system. The resin was used in the sodium form, and buffered to the desired pH. To start an experiment, a solution of polyelectrolyte was mixed with a solution of Eu(III) spiked with Immediately, a small aliquot was removed and forced through a... 

Fig. 3-132. Separation of alkali metals on a latex cation exchanger. - Separator column Fast-Sep Cation I chromatographic conditions see Fig. 3-129.

Fig. 3-134. Separation of alkaline-earth metals on a silica-based cation exchanger. - Separator column Nucleosil 5 SA eluent 0.0035 mol/L oxalic acid + 0.0025 mol/L ethylenediamine + 50 mL/L acetone, pH 4.0 flow rate 1.5 mL/min detection direct conductivity injection volume 100 pL solute concentrations 2.5 ppm magnesium, 5 ppm calcium, 20 ppm strontium, and 40 ppm barium.

Fig. 3-152. Separation of heavy and transition metals on a surface-sulfonated cation exchanger. -Separator column IonPac CS2 eluent 0.01 mol/L oxalic acid + 0.0075 mol/L citric acid, pH 4.2 flow rate 1 mL/min detection photometry at 520 nm after reaction with PAR injection volume 50 pL solute concentrations 5 ppm Fe3+, 0.5 ppm Cu2+, Ni2+, and Zn2+, 1 ppm Co2+, 10 ppm Pb2+, and 5 ppm Fe2+.

Fig. 3-153. Separation of heavy and transition metals on a polymethacrylate-based cation exchanger. - Separator column Sykam LCA A02 eluent 0.1 mol/L tartaric acid, pH 2.95 with NaOH flow rate 2 mL/min detection photometry at 500 nm after reaction with PAR and ZnEDTA injection volume 100 pL solute concentrations 2 ppm Fe3+ and Cu2+, 4 ppm Pb2+, 1 ppm Zn2+, 2 ppm Ni2+ and Co2+, 4 ppm Cd2+, 1.8 ppm Fe2+, 1 ppm Ca2+ and Mg2+.

Indium and gallium are separated by sequential elution from a Dowex-50 cation-exchanger with 0.4 M and 13 M HCl, respectively. Cation exchange in acetone-aqueous HCl gives a very clean separation of Ga, In, Al, and Tl [14]. Ga has been separated from In, Zn, Fe(III), Cu, and other metals by cation exchange chromatography in acetone-aqueous solution of hydrobromic acid [15]. The differences between the stabilities of chloride complexes [16] have permitted anion-exchange separation of Ga from In, Al, and Fe. 

When a sample is dissolved, the phosphorus usually passes into solution as P(V). Rather than isolate the phosphate, it is often better to isolate the interfering elements, leaving the phosphate to be determined in the mother liquor. Examples of such separations include distillation of Si, As, and Ge as volatile halides [1] or of boron as trimethyl borate [2], precipitation of heavy metals as sulphides from an acid medium, retention of cations on a strongly acidic cation exchanger, and electrolytic separation of metals. 

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