Role of stannic phosphate in the uptake of cations. Separation of zirconium from thorium and cadmium from indium at tracer concentrations

The uptake of Na⁺, K⁺, Rb⁺, Cs⁺, Ag⁺, Ca²⁺, Cu²⁺, Sr²⁺, Cd²⁺, Ba²⁺, Pb²⁺, Sc³⁺, Co³⁺, Y³⁺, Sb³⁺, Tb³⁺, Zr⁴⁺ and Th⁴⁺ cations at very small concentrations has been studied over a column of stannic phosphate. The exchanger was prepared by mixing H₃PO₄, NaCl and SnCl₄ in suitable proportions and the ratio of PSn, in the product was obtained to be 1.96. Radiochemical separations of carrier free⁹⁵Zr from²³⁴Th and^115mIn, from¹¹⁵Cd have been carried out by adopting a simple chemical procedure over a column of stannic phosphate. The -spectrum analysis showed that the separated products are of high radionuclidic purity. The separation procedures took less than half an hour with quantitative yield.     

Ceric tungstate as sorbent for polyvalent tracer cations and as an ion exchanger for separation of carrier-free95Nb from95Zr and113mIn from113Sn

The uptake of a few polyvalent ions Ca²⁺ Cu²⁺, Zn²⁺, Cd²⁺, UO²⁺, Cr³⁺, Y³⁺, Ce³⁺, Nd³⁺, Sm³⁺, Tb³⁺, Tm³⁺, Yb³⁺, Lu³⁺, Zr⁴⁺, Hf⁴⁺, Sn⁴⁺, Nb⁵⁺, Se⁶⁺, Mo⁶⁺ and W⁶⁺ at very small concentrations has been studied over ceric tungstate exchanger. A good column variety of the material was prepared by mixing ceric sulphate in 2N H₂SO₄ and aqueous solution of sodium tungstate in suitable proportion. The ratio of cerium: tungstate was obtained to be 11. Separation of carrier-free⁹⁵Nb from⁹⁵Zr and^113mIn from¹¹³Sn have been carried out by applying a very simple chemical procedure over the column of ceric tungstate. The -spectrum of separated⁹⁵Nb and^113mIn products were found to be of high radionuclidic purity. The separation procedure took less than 15 min and the yields were close to 100%.     

Ceric phosphate as ion exchanger in the separation of carrier-free210Bi from210Pb,90Y from90Sr and UX1 from u

Separations of tracer cations in parent daughter systems such as carrier-free²¹⁰Bi from²¹⁰Pb,⁹⁰Y from⁹⁰Sr and UX₁ from U have been carried out in a column of ceric phosphate as ion exchanger. The exchanger has been prepared by mixing ceric sulfate in hot 10M orthophosphoric acid at 80°C and keeping for overnight. A pale yellow coloured precipitate was formed which was washed, dried at 70°C for 48 hours when a hard, granular variety suitable for column use, with a cerium to phosphate ratio of 1∶2 was obtained. 0.1M H₃PO₄ was used as medium in each of the systems studied. The β-decay curves of the separated²¹⁰Bi and⁹⁰Y and the γ-spectrum of UX₁ show that all these activities are radiochemically pure. The separation procedures adopted in each case were very clean and simple, gave quantitative yields and took less than half an hour.     

Reversed phase chromatographic separation of zirconium,niobium and hafnium tracers with HDEHP

Effective separation of the congeneric pair of elements, zirconium and hafnium and also niobium which was in admixtures with zirconium as daughter in its isotopic form were achieved through reversed phase column and paper extraction chromatographic procedures using di-(2-ethylhexyl)phosphoric acid (HDEHP) as the liquid exchanger. In reversed phase column chromatographic separation, the tracers,⁹⁵Zr,⁹⁵Nb and^175,181Hf, were extracted by HDEHP impregnated on kieselguhr and were sequentially eluted with 6N H₂SO₄+xN oxalic acid+H₂O₂(where x=0.1, 0.5 and 2). Similarly, in reversed phase paper chromatographic study in which a coating of HDEHP on Whatman No. 1 chromatographic paper was used as stationary phase, the mobile phase, 18N H₂SO₄+0.1N oxalic acid + H₂O₂, helped in separating the elements with favorable separation factors. Under the optimal conditions, the separation and decontamination of the elements in both methods were found to be quantitative, as verified by -spectrometric studies.     

Study of the state of95Zr+95Nb in aqueous solutions

The adsorption on paraffine and polyethylene and the paper chromatography in aqueous solutions in the pH range of 2–12 were used for the study of the behaviour of⁹⁵Zr and⁹⁵Nb. The effect of complexing ions (SO ₄ ^2? and CO ₃ ^2? ) was studied in the same pH range. The constants of hydrolysis and the composition of hydrolytic species of⁹⁵Zr in the solution containing sulphate ions were determined in the pH range of 1–2. The paper chromatography was used for the control of the purity of⁹⁵Zr after an extractive separation from⁹⁵Nb with α-benzoinoxime. The possibility of studying the extraction processes of Zr (without its previous separation from Nb) by reversed phase chromatography is shown. Conditions for the formation of polynuclear compounds of Zr and Nb and their influence on the extraction separation in nitrate media were studied.     

Separation of carrier-free210Bi and UX1 from210Pb and U,respectively, using silica gel as ion exchanger

Radiochemical separations of carrier-free²¹⁰Bi and UX₁ activities from²¹⁰Pb and U, respectively, have been carried out using a silica gel column.²¹⁰Pb was adsorbed in the column as molybdate and²¹⁰Bi passed unadsorbed. Lead activity was next removed with 25 ml of 0.1 M HNO₃. In the case of separation of UX₁, the coloured carbonate complex of U was removed from the silica surface by washing with saturated sodium carbonate solution, keeping UX₁ retained, and finally UX₁ was washed out with 25 ml of conc. HNO₃. Studies of the beta decay of²¹⁰Bi and the γ-spectrum analysis of UX₁ has shown that the separated products in both cases are of high radiochemical purity. The processes in each case took less than one hour and the yield was satisfactory.     

Studies on the ion-exchange behaviour of chromium ferrocyanide

The sorption of univalent, bivalent and trivalent ions has been studied on chromium ferrocyanide gel. The studies reveal a high sorption capacity for Cs⁺, Tl⁺, Ag⁺, Cu²⁺, Zn²⁺, Cd²⁺, Fe³⁺ and Th⁴⁺. The sorption of monovalent cations show purely ion-exchange mechanism while the uptake of bivalent and trivalent cations is non-equivalent in nature. Single elution of Rb⁺, Cs⁺ and Tl⁺ has been performed from the columns of this exchanger and the recovery is almost complete in all the cases. Cu²⁺ and Ag⁺ get completely adsorbed on the gel column and their elution is not possible probably due to the formation of some new solid phases. Depending on the K_d values of the metal ions, a large number of separations of radiochemical as well as analytical importance can be performed on the columns of this exchanger material.     

Separation of Monovalent and Divalent Cations on a Pure Silica Gel Column with Dilute Oxalic Acid Containing 18-Crown-6 as Mobile Phase

Summary Pure silica gel (Pia Seed 5S-60-SIL) has been investigated as a cation-exchange stationary phase for ion chromatography of common monovalent and divalent cations (Li⁺, Na⁺, NH₄⁺, K⁺, Mg²⁺, and Ca²⁺) with conductimetric detection; dilute oxalic acid (0.05 mm oxalic acid, pH 4.1, to 1 mm oxalic acid, pH 3.0) was used as mobile phase. The Pia Seed 5S-60-SIL silica gel acted as a cation-exchange stationary phase for these cations when 0.2 mm oxalic acid at pH 3.6 was used as the mobile phase. Excellent simultaneous separation and highly sensitive indirect conductimetric detection of these cations were achieved in 20 min on a 150 mm × 4.6 mm i.d. Pia Seed 5S-60-SIL silica gel column with 0.2 mm oxalic acid containing 4 mm 18-crown-6 (1,4,7,10,13,16-hexaoxacycloctadecane), pH 3.7, as mobile phase (detection limits (signal-to-noise ratio, 3, injection volume, 20 L), were 0.15 m for Li⁺, 0.16 m for Na⁺, 0.21 m for NH₄⁺, 1.0 m for K⁺, 0.17 m for Mg²⁺, and 0.25 m for Ca²⁺). The proposed IC–CD method was successfully applied to the separation and detection of major cations (Na⁺, NH₄⁺, K⁺, Mg²⁺, and Ca²⁺) in rain and river water samples.     

Zirconium vanadophosphate as an inorganic ion exchanger

Zirconium vanadophosphate was characterized as a stable inorganic ion exchager. The ion-exchange capacity was measured as 1.75 meq. H⁺ g^?1 at room temperature and it is stable up to 300°C. The exchanger is selective for devalent cations and the order of sorption of cations was found to be M²⁺ > M⁺ > M³⁺ M⁴⁺. Separations of Co²⁺?Ni²⁺, Cu²⁺?Hg²⁺ and Cr(VI)?Cr³⁺ were achieved on a column containing the ion exchanger. Copper could be separated from other base metals in geochemical samples. Differential thermal analysis showed an endothermic peak in the range of 65–420°C due to the dehydration of the ion exchanger with a low activation energy of 7.79 kcal mol^?1, which follows first-order kinetics. The ion exchanger did not show any further decomposition up to 1000°C. Infrared studies confirmed the presence of

groups which act as exchange sites for the cations. X-ray diffraction studies revealed that the compound is crystalline, with a crystal structure resembling that of the mineral muscovite.     

Adsorption of several tracer cations and separation of234Th from238U and113mIn from113Sn on tin dioxide

The uptake of 22 cations at tracer concentrations has been studied over hydrous tin dioxide exchanger material. A granular variety of tin dioxide was prepared from the reaction of tin(IV) chloride with NaOH solution, and the formula of the material was ascertained to be SnO₂·1.7 H₂O. Radiochemical separation of carrier-free²³⁴Th from²³⁸U and^113mIn from¹¹³Sn was achieved over a tin dioxide column. The separated products were of high radionuclidic purity. The overall separation procedures are very simple and quick with quantitative yield.     

Extraction separation of Cs+, Sr2+ and Ba2+ from a mixture of cations forming stable non-extractable complexes with ethylenediamine-N,N, N′,N′-tetraacetic acid in the water-nitrobenzene system

In the two-hase water-nitrobenzene extraction system, a method for gradual separation of Cs⁺, Sr²⁺ and Ba²⁺ from the mixture of cations forming stable non-extractable complexes with ethylenediamine-N, N, N,N-tetraacetic acid in the presence of the sodium salt of dicarbollylcobaltate anion {[-(3)-1, 2-B₉C₂H₁₁]₂ Co(III)}^– and polyethylene glycol ligand with a mean relative molecular mass of 400 (PEG 400), respectively, was developed. In the first extraction step, Cs⁺ was extracted into the organic phase while the other cations studied (Ca²⁺, Sr²⁺, Ba²⁺, Zn²⁺, Co²⁺, Ce³⁺) remained in the aqueous phase. In the second extraction step, Sr²⁺ and Ba²⁺ were extracted into the nitrobenzene phase. Finally, in the following reextraction step, Sr²⁺ was transferred into the aqueous phase while Ba²⁺ remained in the organic phase.     

Effect of the nature and concentration of salting-out agents on the extraction of cobalt(II) from chloride solutions with trialkylamine

The effect of chlorides of Ca²⁺, Ni²⁺, Mg²⁺, Al³⁺, Li⁺, Fe²⁺, Cr³⁺, Na⁺, NH ₄ ⁺ , La³⁺, Nd³⁺ on the extraction recovery of cobalt from chloride solutions with mixtures based on trialkylamine was studied. The series of the salting-out activity of differently charged cations and the degree of their coextraction were determined.     

Sorption of Cs<Superscript>+</Superscript> and Sr<Superscript>2+</Superscript> by ion exchanger based on titanium phosphate

Sorption capacity of a composite ion exchanger based on titanium phosphate for Cs⁺ and Sr²⁺ cations was studied. The effect of pH and concentration of salts and, in particular, sodium chloride in solution on the sorption efficiency and distribution coefficient was analyzed. The diffusion coefficients were calculated for the Cs⁺ and Sr²⁺ cations and the time of half-exchange of the Na⁺ cation for the Cs⁺ and Sr²⁺ cations was found.     

Effect of aryl ligands on the chemical hardness of arylmercury cations

¹⁹F NMR spectroscopy was used to study the exchange reactions involving 4-fluorothiophenoxides, 4-nitrophenoxides, chlorides, and acetates of arylmercury and triphenylphosphinegold. The analysis of the data on equilibrium constants allows one to obtain information on the comparative chemical hardness of ArHg⁺ and Ph₃PAu⁺ cations. The increase in the electron-donating ability of aryl ligands enhances the chemical hardness of ArHg⁺ cations, their influence being best described by ⁰ constants of substituted phenyl groups.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 1255–1260, May, 1996.     

Chloro- und Azidokomplexe des Vanadyl(IV)-Ions in Acetonitril,Propandiol-1,2-carbonat,Trimethylphosphat und Dimethylsulfoxid

The formation of chloro- and azidocomplexes of VO²⁺(IV) is investigated in acetonitrile (AN), propanediol-1,2-carbonate (PDC), trimethyl phosphate (TMP) by spectrophotometric, potentiometric and conductometric methods. The following coordination forms are indicated: [VOCl]⁺ inAN, PDC andDMSO), [VOCl₂] (inAN, PDC andTMP), [VOCl₃]^? (inPDC andTMP[?]), [VOCl₄]^2? (inAN, PDC andTMP); [VON₃]⁺ (inAN, PDC andDMSO), [VO(N₃)₂] (inAN, PDC, TMP andDMSO), [VO(N₃)_2+n]^n? (inAN, PDC, TMP andDMSO). The results are interpreted by the donor numbers and sterical properties of the solvent molecules.     

Crystal structure of tetramethylammonium hexafluoridoniobate(V) and hexafluoridotantalate(V)

Crystal structures of newly synthesized tetramethylammonium hexafluoridoniobate(V) and hexafluoridotantalate(V) (CH₃)₄N[МF₆] (M=Nb, Ta) have been determined; they crystallize in the tetragonal crystal system, sp. gr. P4/nmm. Crystal structures of isostructural compounds (CH₃)₄N[МF₆] (M=Nb, Ta) are formed by virtually regular tetrahedral tetramethylammonium cations (CH₃)₄N⁺ (NMe₄, TMA) and octahedral complex anions [МF₆]^– (M=Nb, Ta), fluorine atoms of the equatorial plane are statistically disordered over two positions. Ionic interactions and weak hydrogen bonds C–H???F join the cations and the complex anions in a 3D assembly.     

Ion-exchange selectivity and chromatographic separation of trivalent metals on titanium antimonate

Summary The ion exchange selectivity of trivalent metal ions has been determined on titanium antimonate cation exchanger prepared by coprecipitation of antimony to titanium at different mole ratios. The selectivity sequence Al³⁺<Cr³⁺<Ga³⁺<In³⁺<Fe³⁺ was found for trivalent metal ions at an initial concentration of 10^–4 mol dm^–3 in nitric acid media. A high separation factor ^Ga/Al = Kd^Ga/Kd^Al, 4.8×10³, was observed for the Ga³⁺–Al³⁺ pair on titanium antimonate with an antimony to titanium ratio of 0.34. The effective separation of Ga³⁺ and In³⁺ from Al³⁺ was achieved using a 3 cm×0.5 cm i.d. column containing titanium antimonate with an antimony to titanium ratio of 0.34.     

Ion-exchange selectivity of a sulfonic cation exchanger based on immobilized cis-tetraphenylcalix[4]resorcinolarene

The ion-exchange equilibrium of protons in SO₃H groups of a sulfonic cation exchanger based on immobilized cis-tetraphenylcalix[4]resorcinolarene with cations of Li⁺, Na⁺, Ag⁺, Cu²⁺, In³⁺, and protonated 1,3,5,7-tetraazaadamantane in aqueous solutions of electrolytes at 293 K was studied. The corrected coefficients of the cation exchange selectivity were calculated.     

Preparation of a hybrid monolithic stationary phase with allylsulfonate for the rapid and simultaneous separation of cations in capillary ion chromatography

A hybrid monolithic column with sulfonate functionality was successfully prepared for the simultaneous separation of common inorganic cations in ion‐exchange chromatographic mode through a simple and easy single‐step preparation method. The strong cation‐exchange moieties were provided directly from allylsulfonate, which worked as an organic monomer in the single‐step reaction. Inorganic cations (Li⁺, Na⁺, K⁺, NH₄⁺, Cs⁺, Rb⁺, Mg²⁺, Ca²⁺, and Sr²⁺) were separated satisfactorily by using CuSO₄ as the eluent with indirect UV detection. The allysulfonate hybrid monolith showed a better performance in terms of speed and pressure drop than the capillary packed column. The number of theoretical plates achieved was 19 017 plates/m (in the case of NH₄⁺ as the analyte). The relative standard deviations (n = 6) of both retention time and peak height were less than 1.96% for all the analyte cations. The allysulfonate hybrid monolithic column was successfully applied for the rapid and simultaneous separation of inorganic cations in groundwater and the effluent of onsite domestic wastewater treatment system.     

Synthesis and complexing properties ofcis,cis-1,3,5-tri-[2-(diphenylphosphinyI)ethylamino]cyclohexane

A novel polydentate phosphorus-containing complexing agent,cis,cis-1,3,5-tri[2-(diphenyl-phosphinyl)ethylamino]cyclohexane, has been prepared on the basis ofcis,cis-1,3,5-triamino-cyclohexane. The method of potentiometric titration in an aqueous—organic medium (70% ethanol, ionic strength 0.01M LiNO₃, 298 K) has been used to study the acid-base and complexing properties of the title compound. The ligand thus prepared forms 11 complexes with Cu²⁺, Co²⁺, Zn²⁺, and Ni²⁺ cations; formation of hydroxocomplexes MOHL⁺ has been observed in the case of Zn²⁺ and Cd²⁺.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1276–1279, July, 1993.The authors are grateful to A. G. Matveeva for his assistante in discussing the results of this study and in preparing this paper.