Preparation of99Mo,132Te isotopes and99mTc,132I generators

Adsorption and desorption of⁹⁵Zr−⁹⁵Nb,⁹⁹Mo,¹⁰³Ru,¹³²Te and²³⁹Np in a HCl-alumina system were studied in order to purify⁹⁹Mo and¹³²Te obtained by the cation-exchange separation of fission products and to prepare highly pure^99mTc and¹³²I generators.⁹⁹Mo and¹³²Te, of which radionuclidic purity was over 99.99% and 99.999%, respectively, could be obtained by passing the cation-exchange separated Mo and Te fractions through alumina columns, by washing with HCl and finally by eluting⁹⁹Mo with 1M NH₄OH and¹³²Te with 3M NaOH. In order to raise the recovery of⁹⁹Mo and¹³²Te from the alumina columns, they should be eluted as quickly as possible after the adsorption. The direct use of the alumina column containing⁹⁹Mo or¹³²Te as the generator allowed milking of^99mTc or¹³²I, of which radionuclidic purity was over 99.999%. Milking yields of^99mTc with 0.1M HCl and¹³²I with 0.01M NH₄OH were 77% and 90%, respectively. The latter value was much higher than that in usual performance of the generator.     

Separation of radioindium (N.C.A.) from neutron irradiated tin and cadmium on hydrated antimony pentoxide

Hydrated antimony pentoxide (HAP) as an absorbent for column operation has been prepared by hydrolysis of SbCl₅ with deionized water. Sorption behavior of Sn, Cd, Sb and In was studied on HAP in HCl medium. Radiochemical separation of no-carrier added^113mIn from¹¹³Sn/¹²⁵Sb and^115mIn from¹¹⁵Cd wa achieved over a HAPO column. The separated products were of high radionuclidic purity.     

115Cd photonuclear production for115Cd−115mIn generator

Production of¹¹⁵Cd by means of photonuclear reaction and preparation of a^115mIn generator, based on the genetic sequence of¹¹⁵Cd^115mIn, were studied. The production rates of¹¹⁵Cd by the¹¹⁶Cd(γ, n)¹¹⁵Cd reaction were determined as a function of the maximum bremsstrahlung energies between 35 and 60 MeV. Then the parent,¹¹⁵Cd, was produced by irradiating about 0.15g of CdO with the bremsstrahlung from a 60 MeV-150 μA electron beam. After the parent in the Cd ₄ ²⁻ form was adsorbed on the Dowex 1x8 resin column, the daughter was eluted with a physiologic saline adjusted to pH 1. The generator was milked over a period of 3 days, during which time about 900 ml of eluent were allowed to flow through the column. Even after the milkings were repeated 15 times with 60 ml of the eluent, no¹¹⁵Cd was found in the^115mIn fractions (the detection limit of inactive cadmium: 0.02 μg).     

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.     

Separation of99Mo from132Te using thiourea as complexing agent. Application to the separation of99Mo from fission products

A radiochemical method to isolate⁹⁹Mo from¹³²Te, both produced in the fission of²³⁵U, has been developed. The method is based on the formation of a cationic complex of tellurium with thiourea in acid medium which is retained (98.7±0.5)% on a cation exchange resin (Dowex 50W-X8, 100–200 mesh), while (99.8±0.05)%⁹⁹Mo passes through it, due to the non-formation of such complex in the same experimental conditions. The radionuclidic purity of⁹⁹Mo was found to be suitable for the preparation of⁹⁹Mo–^99mTc generators. The retention of⁹⁹Mo on an alumina column as a function of pH was investigated and the best pH range for this purpose was found to be 4.0–4.5.     

Simple indium generators

Very economical, rapid and pure methods for the production of^115mIn and^113mIn from¹¹⁵Cd and¹¹³Sn, respectively are described. The methods are based on the extraction of^115mIn by o-xylene from 7.2M H₂SO₄ −0.06M HBr, and its reextraction with ≈11M H₂SO₄ −0.06M HBr from n-hexane. The γ-spectra of the generated^115mIn and^113mIn indicate that they are free from any other interferences.     

Use of zirconium phosphate as ion exchanger in some parent-daughter radioisotope separations

Zirconium phosphate as ion exchanger suitable for column operation has been prepared by mixing hot metaphosphoric acid solution with a solution of zirconium oxychloride when the white insoluble phosphate separated out which was dried and purified. The ratio of zirconium: phosphate was found to be 1:2. Separation of parent-daughter systems like¹¹⁵Cd-^115mIn,¹⁴⁴Ce-¹⁴⁴Pr and²¹⁰Pb-²¹⁰Bi were carried out with this exchanger. γ-ray spectrum of the separated^115mIn and the β-decay curve of¹⁴⁴Pr and²¹⁰Bi showed that all the daughter activities are radiochemically pure. The separation process in each case takes less than half an hour and the yield is quantitative.     

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%.     

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.     

Technetium-99m generator based on 12-molybdocerate —99Mo precipitate as column matrix

The preparation of insoluble 12-molybdocerate(IV) from⁹⁹Mo of low specific activity, produced by thermal neutron irradiation of MoO₃, is described. Samples of the material are dried at 50, 100 and 200°C and used as column matrices from which the generated^99mTc activity is periodically eluted with saline solution or saline solution containing 5·10^–5M K₂CrO₄ as an oxidant. The elution yields of^99mTc are high and reproducible (95–81%) with radionuclidic purity 99.98%. Both chemical and radiochemical purity (as TcO ₄ ^– ) of the eluates decrease with increasing drying temperature of the column matrix. Using chromated saline solution as eluent improves the radiochemical purity of the^99mTc eluate.     

Adsorption of tracer cations,and the separation of carrier-free95Nb from95Zr,XU1 from U and45Ca from46Sc on titanium phosphate column

Titanium phosphate as ion exchanger for column operation has been prepared by mixing TiCl₄ and H₃PO₄ in suitable proportion. The ratio of titanium: phosphate was obtained to be 1:2.02. The uptake of Na⁺, K⁺, Rb⁺, Cs⁺, Ag⁺, Ca²⁺, Sr²⁺, Ba²⁺, Pb²⁺, Sc³⁺, Co³⁺, Y³⁺, Tb³⁺, Zr⁴⁺ and Th⁴⁺ cations at very small concentrations has been studied on this exchanger. The data indicated that the different cations are adsorbed in the exchanger by different mechanisms. Radiochemical separations of carrier free⁹⁵Nb from⁹⁵Zr, UX₁ from U and⁴⁵Ca from⁴⁶Sc have been achieved by adopting very simple chemical procedures through a column of titanium phosphate. The -spectrum of the separated⁹⁵Nb, UX₁ and⁴⁶Sc showed that the products are of high radionuclidic purity. The individual separation procedures took less than 20 min and the yields are quantitative.     

Preconcentration of radioiodine as AgI and purification from radiotellurium waste

A radiochemical method was investigated for separation and preconcentration of radioiodine from alkaline radiotellurium waste solution as Ag¹²⁵I followed by recovery of ¹²⁵I into aqueous NH₃ solution and final purification by wet distillation. ¹²⁵I–^123mTe radiotracer solution (5 M NaOH) was equilibrated with prepared silver granules for different times and it was found that ¹²⁵I was quantitatively removed from the aqueous phase after 7.0 h. The ¹²⁵I-loaded silver was then equilibrated with ammonia solution in the presence of one of different reducing agents (namely, sodium borohydride, dextrose and zinc dust). Different concentrations of NH₃ solution and reducing agents were studied. Quantitative recovery of ¹²⁵I in the aqueous phase was achieved after 1.0 h of equilibration of ¹²⁵I-loaded silver granules with 2.7M NH₃ solution in the presence of Zn dust with a Zn:Ag molar ratio of 0.5. Purification of the recovered ¹²⁵I was carried out by wet distillation from 20 % H₂SO₄ in the presence of H₂O₂. The distilled off ¹²⁵I was received in a mixture solution of 0.1M NaOH and 0.01M Na₂S₂O₃ with a radionuclidic purity of ≥99.99 %, radiochemical purity of ~98.8 % (as I^? anions) and pH-value of ~13.     

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.     

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.     

Separation of In3+ from Cd2+ on crystalline antimonic acid.115Cd−115mIn generator

The distribution coefficients of Cd²⁺ and In³⁺ on crystalline antimonic(V) acid (C-AA) have been determined in order to find the best conditions for separation of both cations. Very high affinity of C-AA for Cd²⁺ ions enables to separate^115mIn from¹¹⁵Cd in a single-step rapid procedure. The indium fraction obtained was very pure; the amount of radioactive contaminants was less than 0.0005%.     

Radiochemical separation of99Mo from natural uranium irradiated with thermal neutrons

⁹⁹Mo was separated from uranium and insoluble fission product hydroxides. More than 98% of⁹⁹Mo radioactivity was extracted with bis (2-ethylhexyl)phosphoric acid. The organic phase was washed and⁹⁹Mo was back-extracted from the organic phase with NH₄OH solution. The percent recovery from the organic phase was 91% and the purity of⁹⁹Mo was more than 99%. Pure^99mTc was also extracted from the organic phase with a saline solution. Reversed-phase partition chromatography was used for the purification of⁹⁹Mo from¹³¹I and other fission products (10% HDEHP on kieselguhr bed).¹³¹I and other isotopes were quantitatively eluted with 0.1M H₂SO₄,⁹⁹Mo was eluted using a mixture of 0.5 M HCl and 30% H₂O₂.     

Use of Adogen-464 in some parent — daughter separations by reverse phase extraction chromatography

Seperation of few carrier-free daughter isotopes from their respective parents, e.g.,¹³²I from¹³²Te,¹⁴⁰La from¹⁴⁰Ba and²³⁴Th from²³⁸U, using Adogen-464, a high molecular weight quaternary ammoaium salt by reversed phase extraction chromatographic technique is reported.     

Radiochemical separation of110mAg,210Pb,127Te and131I from aqueous nitric acid solution by bis-2-(butoxyethyl ether)

A bis-2-(butoxyethyl ether) (DBC) solvent extraction method has been developed for the radiochemical separation of^110mAg,²¹⁰Pb,¹²⁷Te and¹³¹I in varying concentrations of aqueous HNO₃. Various factors were examined to determine the optimum conditions of extraction. The effect of various masking agents has been studied. The extraction of¹³¹I is enhanced to 99% at 2.4M HNO₃ in the presence of KSCN.¹³¹I was stripped into aqueous sodium hydroxide from the oxygenated organic extractant. The method was then applied for the recovery of¹³¹I from neutron irradiated tellurium metal. The mechanism and reactivity of DBC with metal ions is described.     

Radiochemical determination of Mo in pure tungsten

A radiochemical neutron activation technique for Mo determination in high purity tungsten, based on some specific properties of Mo and W radionuclides has been developed. Al₂O₃ powder has been used as a sorbent. An estimation of the Mo content was carried out via the selectively separated^99mTc daughter radionuclide. Limit of detection was 10 ng g^–1.     

Elution of 235U fission products through a calcined hydrotalcite-packed column

Calcined hydrotalcite packed columns were utilized to sorb ²³⁵U fission products and their decay products. The elution behavior of some radionuclides was studied after washing the columns, either with distilled water or 0.5% NaCl solution. Afterwards, fission products and their decay products were eluted using 0.5% NaCl solution. It was found that no matter the washing process, ^99mTc, the b^--decay product of ⁹⁹Mo, was easily separated from ⁹⁹Mo which was strongly retained on the hydrotalcite. ¹³²I, the b^--decay product of ¹³²Te, was eluted slowly and was separated from ¹³²Te which was retained on the column. ¹³¹I and ¹⁴⁰Ba were eluted together with ^99mTc and ¹³²I, although in smaller proportions.