Distribution coefficients and cation-exchange behaviour of 45 elements with a macroporous resin in hydrochloric acid/methanol mixtures

Cation-exchange distribution coefficients are presented for 45 elements with the macroreticular (macroporous) cation-exchange resin AG MP-50 in mixed hydrochloric acid/methanol media, with acid concentrations ranging from 0.5 to 6.0 M, and methanol concentrations from 0 to 90%. The ion-exchange behaviour of the elements is discussed, some possible separations are indicated, and 3 multi-element elution curves are presented, demonstrating the separations of the combinations In-Zn-Ga-Al-Yb; Cd-Li-Cu(II)-Mg-Ca; and Pt(IV)-Te(IV)-V(IV)-Fe(III)-Mn(II).     

Quantitative separation of gold from cadmium, indium, zinc and other elements by cation-exchange chromatography in hydrochloric acid-acetone medium

Gold(III) can be separated from Cd, In. Zn, Ni, Cu(II), Mn(II), Co(II), Mg, Ca, Al, Fe(III), Ga and U(VI) by adsorbing these elements on a column of AG50W-X8 sulphonated polystyrene cation-exchange resin from 0.1M HCl containing 60% v v acetone, while Au(III) passes through and can be eluted with the same reagent. Separations are sharp and quantitative. The amounts of gold retained by the resin are between 1 and 2 orders of magnitude lower than encountered during adsorption from aqueous 0.1M HCl. Recoveries for mg amounts of gold are 99.9% or better and for ng amounts are still better than 99%, as shown by radioactive tracer methods. Hg(II), Bi, Sn(IV), the platinum metals and some elements which tend to form oxy-anions in dilute acid accompany gold. All other elements, though not investigated in detail, should be retained, according to their known distribution coefficients. Relevant elution curves, results of quantitative separations of binary mixtures and of recovery tests are presented.     

Selective separation of uranium from other elements by cation-exchange chromatography in hydrobromic acid and hydrochloric acid-acetone mixtures

U(VI) can be separated from Ga, Fe(III), Bi, Pb, Cd, Zn, Cu(II) and Au(III) by quantitative elution with 0.50M HBr in 86% acetone or with 0.35M HBr in 90% acetone from a column of AG50W-X4 cation-exchange resin of 200-400 mesh particle size. U(VI) and many other ions are retained. U(VI) then can be eluted selectively with 0.50M HCl in 83% acetone or with 0.35M HCl in 85% acetone. Co(II), Mn(II), Mg, Ca, Ti(IV), Al, Zr, Th and La are quantitatively retained by the column. These elements then can be eluted with 5M HNO(3). At the higher acid concentration (0.50M) the separation between U(VI) and Li is not satisfactory but is excellent at the lower acid concentration; the U(VI) peak is sharper at the higher acid concentration. Separations are sharp and quantitative, as is demonstrated by results for some synthetic mixtures. Distribution coefficients and elution curves are presented.     

Distribution coefficients for twelve elements in oxalic acid medium on a strong anion-exchange resin

The distribution coefficients were determined for twelve elements, namely As(III), Ce(III), Cr(III), Co(II), Cu(II), In(III), Lu(III), Mn(II), Hg(II), Mo(VI), Sc(III) and Zn(II), on a strong base anion exchanger in pure oxalic acid solutions. The K_D curves are given. A scheme was developed for the chromatographic separation of five elements, namely As(III), Mn(II), Co(II), Zn(II) and Cu(II). Ce(III) can be separated from Lu(III).     

Selective separation of indium from zinc, lead, gallium and many other elements by cation-exchange chromatography in hydrohalic acid-acetone medium

Indium can be separated from Zn, Pb(II), Ga, Ca, Be, Mg, Ti(IV), Mn(II), Fe(III), Al, U(VI), Na, Ni(II) and Co(II) by selective elution with 0.50M hydrochloric acid in 30% aqueous acetone from a column of AG50W-X8 cation-exchange resin, all the other elements being retained by the column. Lithium is included in the elements retained by the column when 0.35M hydrochloric acid in 45% aqueous acetone is used for eluting indium, but the elution of indium is slightly retarded. Ba, Sr, Zr, Hf, Th, Sc, Y, La and the lanthanides, Rb and Cs should also be retained according to their distribution coefficients. Cd, Bi(III), Au(III), Pt(IV), Pd(II), Rh(III), Mo(VI) and W(VI) can be eluted with 0.20M hydrobromic acid in 50% aqueous acetone before the elution of indium, and Ir(III), Ir(IV), As(III), As(V), Se(IV), Tl(III), Hg(II), Ge(IV), Sb(III) and Sb(V), though not investigated in detail, should accompany these elements. Relevant distribution coefficients and elution curves and results for analyses of synthetic mixtures of indium with other elements are presented.     

Quantitative separation of calcium from magnesium,aluminium, iron(III) and many other elements by cation-exchange chromatography in methanolic hydrochloric acid on a macroporous resin

Calcium can be separated from Mg, Al, Cu(II), Fe(III), Ga, Zn, Mn(II), Co(II), U(VI) and Ti(IV) by cation-exchange chromatography on a column of AG MP-50 macroporous resin. Sr, Ba, Sc, Y, the lanthanides, Zr, Hf and Th are retained together with calcium. The separation factor for the Ca—Mg pair in 3 M HCl containing 50% methanol is about 20 which is considerably larger than those obtained by other ion-exchange procedures. Separations with the cation-exchange resin are sharp and quantitative. A column containing only 2 g (5.4ml) of resin is sufficient to separate up to 0.2 mmol of calcium from 2 mmol of magnesium and larger amounts of Fe(III), Cu(II) and Zn. On a 10-g column, up to 2.5 mmol of calcium can be separated easily from similar and larger amounts of other elements. Distribution coefficients for calcium and magnesium with variation of cross-linkage and variation of methanol concentration are presented, together with relevant elution curves and results for synthetic mixtures.     

Distribution coefficients and cation-exchange selectives of elements with AG50W-X8 resins in perchloric acid

Cation-exchange distribution coefficients with AG50W-X8, a sulphonated polystyrene resin, aie presented for 44 cations in perchloric acid solutions of concentrations varying from 0.1 to 4.0M. The cations are arbitrarily arranged in a table according to their distribution coefficients in 1.OM perchloric acid. Some possible separations are discussed and elution curves are presented for the separation of the ion pairs Zn-Pb, Tl(I)-Bi, Mg-Al and Co(II)-Fe(III). Selectivity sequences for uni-, bi-, ter- and quadrivalent cations are given in which the cations are ordered on the basis of the average numerical value of their distribution coefficients over the straight part of the curve obtained by plotting the logarithm of the distribution coefficient against the logarithm of [H(+)].     

Distribution coefficients and ion exchange behaviour of some elements with Purolite S-950 in hydrochloric acid

Equilibrium distribution coefficients, K_d, are presented for some elements in hydrochloric acid using the phosphonated polystyrene ion exchange resin Purolite S-950. A few possible separations using this resin are demonstrated by elution curves and separations of synthetic mixtures of some elements (Ru, Rh, Mo, I, Li, Te, Si, Y).     

Selective and quantitative separation of zinc and lead from other elements by cation-exchange chromatography in hydrohalic acid-acetone solutions

Zinc and lead can be separated from Cd, Bi(III), In and V(V) by eluting these elements with 0.2M hydrochloric acid in 60% acetone from a column of AG50W-X8 cation-exchange resin, zinc and lead being retained. Mercury(II), Tl(III), As(III), Au(III), Sn(IV), Mo(VI), W(VI) and the platinum metals have not been investigated quantitatively, but from their distribution coefficients, should also be eluted. Vanadium(V), Mo(VI) and W(VI) require the presence of hydrogen peroxide. Zinc and lead can be eluted with 0.5M hydrochloric acid in 60% acetone or 0.5M hydrobromic acid in 65% acetone and determined by AAS; the alkali and alkaline-earth metal ions, Mn(II), Co, Ni, Cu(II), Fe(III), Al, Ga, Cr(III), Ti(IV), Zr, Hf, Th, Sc, Y, La and the lanthanides are retained on the column, except for a small fraction of copper eluted with zinc and lead. Separations are sharp and quantitative. The method has successfully been applied to determination of zinc and lead in three silicate rocks and a sediment.     

Quantitative separation of gallium from zinc, copper, indium, iron(III) and other elements by cation-exchange chromatography in hydrobromic acid-acetone medium

Gallium can be separated from Zn, Cu(II), In, Cd, Pb(II), Bi(III), Au(III), Pt(IV), Pd(II), Tl(III), Sn(IV) and Fe(III) by elution of these elements with 0.50M hydrobromic acid in 80% acetone medium, from a column of AG50W-X4 cation-exchange resin. Gallium is retained and can be eluted with 3M hydrochloric acid. Separations are sharp and quantitative except for iron(III) which shows extensive tailing. With 0.20M hydrobromic acid in 80% acetone as eluting agent, all the species above except iron(III) and copper(II) can be separated from gallium with very large separation factors. Only a 1-g resin column and small elution volumes are required to separate trace amounts and up to 0.5 mmole of gallium from more than 1 g of zinc or the other elements. Hg(II), Rh(III), Ir(IV), Se(IV), Ge(IV), As(III) and Sb(III) have not been investigated, but should be separated together with zinc according to their known distribution coefficients. Relevant elution curves, results for the analysis of synthetic mixtures and for amounts of some elements remaining in the gallium fraction are presented.     

Distribution coefficients and cation-exchange behaviour of some ammines and aquo complexes of metallic elements in ammonium nitrate solution

Comparative cation-exchange distribution coefficients of ammines and aquo complexes of Cu(II), Ni(II), Cd, Zn, Ag, Co(II)/(III), Hg(II), Pd(II), Au(III) and Pt(II) were determined in 0.1, 0.2, 0.5 and 1.0 M ammonium nitrate solution. The values for mercury(II) in ammonium chloride and of the ammine of copper(II) in ammonium citrate and ammonium sulphosalicylate solutions were also measured. The ion-exchange behaviour of the ammines is discussed and some possible separations are demonstrated by the experimental elution curves for the ion pairs Mg-Ni(II), Ca-Zn, Yb-Cd and Fe(III)-Cu(II).     

Comparative distribution coefficients and cation-exchange behaviour of the alkaline earth elements with various complexing agents

Equilibrium distribution coefficients are presented for the alkaline earth metals Be(II), Mg(II), Ca(II), Sr(II) and Ba(II) with the complexing agents acetate, formate, lactate, citrate, tartrate, alpha-hydroxyisobutyrate, malonate, malate, acetylacetonate, EDTA, EGTA and DCTA, and the AG50W-X8 cation-exchange resin. Coefficients in HCl, HNO(3), HClO(4) and NH(4)Cl are included for the sake of completeness. The merits of the various complexing agents for the separation of adjacent element pairs are discussed and experimental elution curves are presented for selected separations. Separation factors for adjacent elements are calculated at eluting agent concentrations corresponding to a distribution coefficient of 10 for the less strongly absorbed element and are presented together with the eluting agent concentrations to form a basis for comparison.     

Synthesis and efficiency of a spherical macroporous epoxy-melamine chelating resin for preconcentrating trace elements from solutions

A new spherical macroporous epoxy-melamine chelating resin was synthesized simply and rapidly and used for the preconcentrating and separation of trace of Ga(III), In(III),Bi(III), Sn(IV)and Ti(IV) ions from sample solutions. The ions analyzed can be quantitatively enriched by the resin at a flow-rate of 2ml/min at pH4,and quantitatively desorbed with 10ml of 2mol/L HCl+0.2gCS(NH₂)₂ at a flow-rate of 1ml/min with recoveries of over 97%,The chelating resin can be reused 7times without obvious loss of efficiency.     

The influence of thiourea on the cation-exchange behaviour of various elements in dilute nitric and hydrochloric acids

Cation-exchange distribution coefficients for 21 elements between the cation-exchange resin AG50W-X4 and dilute nitric and hydrochloric acid containing up to 2.0M concentration of thiourea are presented. The ion-exchange behaviour of the elements and some possible separations are discussed. Four multi-element elution curves are presented, demonstrating the separation of the combinations Ga(Ag, Cu)Zn(Cd, Pb, In, Sn[IV]), CoPbSbTe, ZnCdBiHg, and AgCdInAu.     

High-speed ion-exclusion chromatography of dissolved carbon dioxide on a small weakly acidic cation-exchange resin column with ion-exchange enhancement columns of conductivity detection

The high-speed ion-exclusion chromatographic determination of dissolved carbon dioxide, i.e., carbonic acid, hydrogencarbonate or carbonate, with conductivity detection was obtained using a small column packed with a weakly acidic cation-exchange resin in the H+-form (40 mm long x 4.6 mm i.d., 3 microm-particle and 0.1 meq./ml-capacity). Two different ion-exchange resin columns, which were a strongly acidic cation-exchange resin in the K+-form and a strongly basic anion-exchange resin in the OH- -form, were connected after the separation column. The sequence of columns could convert dissolved carbon dioxide to KOH having high conductivity response. The enhancement effect for dissolved carbon dioxide could retain even on the vast chromatographic runs, by using the enhancement columns with high ion-exchange capacity above 1.0 meq./ml. The retention time was in 60 s at flow-rate of 1.2 ml/min. The calibration graph of dissolved carbon dioxide estimated as H2CO3- was linear in the range of 0.005-10 mM. The detection limit at signal to noise of 3 was 0.15 microM as H2CO3-. This method was applicable to several rainwater and tap water samples.     

Separation of silver from zinc, cadmium, copper, nickel and other elements in nitric acid with a macroporous resin

Traces of silver and amounts up to 50 mg can be separated from up to gram amounts of Zn, Cu(II), Ni, Co(II), Mg, Be, Ti(IV), V(IV), Li and Na by eluting these with 2.0M nitric acid from a column containing 54 ml (20 g) of macroporous AG MP-50 cation-exchange resin of 100-200 mesh particle size, in the H(+)-form. Silver is retained and can be eluted with 0.5M hydrobromic acid in 9:1 v v acetone-water. Separations are sharp and quantitative and only a few microg of the other elements are found in the silver fraction. Cadmium and manganese (II) can also be separated quantitatively but show tailing and require larger elution volumes. Some typical elution curves and results of analyses of synthetic mixtures are presented.     

Separation of beryllium and aluminium from other elements using an ion-exchange resin with N-benzoylphenylhydroxylamine as a functional group

A chelating polystyrene-divinylbenzene-based resin containing N-benzoylphenylhydroxylamine as the chelating group was synthesized and characterized through its water regain capacity (0.56 g g^?1) and stability towards acids, alkalis, heat and γ-radiation. The effective pH for use of the resin was 1.0–7.0 for beryllium, 2.5 for aluminium and 6.5 for coppjt]Analyst     

Simultaneous ion-exclusion/cation-exchange chromatography of anions and cations in acid rain waters on a weakly acidic cation-exchange resin by elution with sulfosalicylic acid

A simple, selective, and sensitive method for the simultaneous determination of anions (sulfate, nitrate, and chloride) and cations (sodium, ammonium, potassium, magnesium, and calcium) in acid rain waters was developed using ion-exclusion/ cation-exchange chromatography with conductimetric detection. A weakly acidic cation-exchange resin column (Tosho TSKgel OA-PAK-A) and a sulfosalicylic acid-methanol-water eluent was used. With a mobile phase comprising 1.25 mM sulfosalicylic acid in methanol-water (7.5:92.5) at 1.2 ml/min, simultaneous separation and detection of the above anions and cations was achieved in about 30 min. Linear calibration plots of peak area versus concentration were obtained over the concentration ranges 0-1.0 mM for anions (R=0.9991) and 0-0.5 mM for cations (R=0.9994). Detection limits calculated at S/N=3 ranged from 4.2 to 14.8 ppb for the anions and from 2.4 to 12.1 ppb for the cations. The reproducibility of retention times was 0.14-0.15% relative standard deviation (RSD) for anions and 0.18-0.31% for cations, and reproducibility of chromatographic peak areas was 1.22-1.75% RSD for anions and 1.81-2.10% for cations. The method was applied successfully to the simultaneous determination of anions and cations in aerosols transported from mainland China to central Japan, as determined by a meteorological satellite data analyzer.