Synthesis of maghemite nano-particles and its application as radionuclidic adsorbant to purify <Superscript>109</Superscript>Cd radionuclide

Maghemite nano-particles were synthesized by a solid-state chemical reaction for its highly selective use as, cyclotron-produced, ¹⁰⁹Cd (462.9 days) purification method of choice. ¹⁰⁹Cd radiochemical separation starts with Ag activities precipitated with HCl 0.0015 M followed by, on a second step, ¹⁰⁹Cd separation from Cu carrier and ⁶⁵Zn (243.8 days) using Ca (NO₃)₂ 0.01 M. Experimental parameters such, pH and sorbent concentration, on ¹⁰⁹Cd extraction efficiency were investigated. Phase morphology, nanostructure and size of nano-particles were studied by X-ray diffraction (XRD) and scanning electron microscopy (SEM). A 10–20 nm average grain size was derived from XRD line broadening and SEM data. Heat treatment on Fe³⁺:Fe²⁺ ratios equal to 2:1, produced powders, resulting in tetragonal (maghemite) structure at 300 °C and rhombohedra (hematite) at 600 °C. ¹⁰⁹Cd chemical and radionuclidic purity were determined by ICP-AES and HPGe detector gamma-ray spectrometry. The overall recovery and radionuclide purity were 80.0% from obtained 129.63 kBq/C MeV (70 kBq/μAh) initial activity and 91.4%, respectively.     

Separation of no-carrier-added 109Cd from natural silver target using RTIL 1-butyl-3-methylimidazolium hexafluorophosphate

The room temperature ionic liquid (RTIL), 1-butyl-3-methylimidazolium hexafluorophosphate [C₄mim][PF₆] has various applications in the separation of a range of metal ions replacing volatile and toxic traditional organic solvents in liquid–liquid extraction systems. In this study, the RTIL [C₄mim][PF₆] was used to separate no-carrier-added (NCA) ¹⁰⁹Cd from α-particle irradiated Ag target. A natural Ag foil was bombarded by 30 MeV α-particles to produce ¹⁰⁹Cd. After the decay of all co-produced short-lived products, NCA ¹⁰⁹Cd was separated from the bulk Ag using [C₄mim][PF₆] as extractant from HNO₃ medium. Ammoniumpyrrolidine dithiocarbamate (APDC) was used as a complexing agent. At the optimum condition, 3 M HNO₃, 0.01 M APDC in presence of [C₄mim][PF₆], ~99 % bulk Ag was extracted to the IL phase, leaving NCA ¹⁰⁹Cd in the aqueous phase. The amount of Ag became negligibly small after re-extraction in the same condition. The ionic liquid was recovered by washing it with 1 M HCl.     

Simultaneous production and separation of no-carrier-added 111In, 109Cd from alpha particle induced silver target

A natural silver foil was bombarded by 30 MeV α-particles which produced ¹¹¹In, ¹⁰⁹Cd and ^106mAg in the target matrix. ¹¹¹In and ¹⁰⁹Cd were separated from the Ag target matrix employing ion-exchange chromatography and liquid–liquid extraction (LLX). In the chromatographic separation, the active solution containing the NCA products were adsorbed in the column containing Dowex 50 and were eluted with HNO₃. Bulk silver and ¹⁰⁹Cd were sequentially eluted with 1 M HNO₃. After complete elution of ¹⁰⁹Cd and the bulk, ¹¹¹In was eluted with 1.5 M HNO₃. In the LLX, the NCA ¹¹¹In was extracted to 1 % HDEHP (di-2(ethylhexyl)phosphoric acid) from 10^?2 M HNO₃ solution, leaving cadmium and bulk silver quantitatively in the aqueous phase. The NCA ¹⁰⁹Cd was separated from the bulk Ag by precipitating Ag as AgCl. NCA ¹¹¹In was stripped back quantitatively from HDEHP phase using 8 M HNO₃.     

The production of 103Pd and 109Cd from a proton irradiated tandem natAg/natAg targets

This paper describes a new method for the production of ¹⁰³Pd and ¹⁰⁹Cd using the 66 MeV proton beam of iThemba LABS on a tandem natural silver target (Ag/Ag). The radiochemical separation of the Pd radionuclides (¹⁰³Pd, ¹⁰⁰Pd) from the bulk ^natAg was done using a Chelex-100 chelating resin column. The recovery of ¹⁰³Pd from the irradiated ^natAg target was found to be >98 % without any Ag or Rh impurities detected. The radiochemical separation of ¹⁰⁹Cd from the bulk ^natAg target was done by the precipitation of Ag ions by Cu followed by the separation of ¹⁰⁹Cd, traces of Ag, Cu²⁺ and Rh using a AG1-X10 anion exchange resin column. The recovery yield of ¹⁰⁹Cd was >99 % without any Ag or Rh impurities detected.     

Ionic liquid-salt based aqueous biphasic system for separation of 109Cd from silver target

Aqueous biphasic system (ABS) is greener alternative to the conventional liquid liquid extraction as ABS does not involve any organic or volatile reagents. Generally ABS systems are composed of polymer and salt rich phases. In this paper a new ABS system is proposed replacing polymer rich phase by water soluble room temperature ionic liquid (RTIL) 1-butyl-3-methylimidazolium Chloride ([bmim]Cl) and kosmotropic salt K₂HPO₄. The system has been applied to separate the no-carrier-added (NCA) ¹⁰⁹Cd (T _1/2 = 462.6 days) from the α-particle irradiated bulk Ag target. The optimum separation condition was achieved with the addition of 6 M HNO₃ to the ABS, where ~87 % of the bulk Ag was extracted in the IL phase, leaving ~96 % NCA ¹⁰⁹Cd in the salt rich phase. The salt rich phase was re-extracted twice with the RTIL to free from bulk Ag. This process achieved an overall separation of 91 % NCA ¹⁰⁹Cd free from bulk Ag. The developed method demonstrates minimum requirement of RTIL to carry out the separation. The method is environmentally benign and cost effective.     

Radiochemical separation of 109Cd from a silver target

A radiochemical separation method was developed for the separation of ¹⁰⁹Cd from a ^nat.Ag target (6.6 g, pressed into a 19 mm disc). The method comprised of two stages. In the first stage, after dissolution of the target in nitric acid, silver was separated from Cd by precipitation into the metallic form using 20 g of Cu turnings for the reduction of Ag⁺ ions. In the second stage, ¹⁰⁹Cd in the filtrate, that contained trace amount of silver and substantial quantity of Cu(I), was purified by use of a Bio-Rad AG1-X10 anion-exchange resin. The ion-exchange chromatography employed a column with (1.6 cm i.d. and 4 cm length) with a flow rate of 2 ml/min throughout the separation. ¹⁰⁹Cd was quantitatively recovered from the first stage and the recovery yield from the ion-exchange chromatography was greater than 96%. 2M HCl containing H₂O₂ was used for the adsorption of ¹⁰⁹Cd and elution of Cu. ¹⁰⁹Cd was eluted by 50 ml 1M HNO₃. The concentrations of stable isotopes of Ag and Cu in the final solution (5 ml 0.05M HCl) were measured by an ICP-OES method and found to be <1 ppm.     

Chemical separation of enriched cadmium target from copper backing in cyclotron production of radioisotope 111In

A radiochemical purification procedure was developed for the separation of enriched cadmium (¹¹¹Cd and ¹¹²Cd) from natural copper that used as backing; and was based upon the chromatographic adsorption. The separation of copper from cadmium was studied in this work. The ions were selectively separated from aqueous solution. Ion-exchange chromatography was employed as a column (1.5 cm i.d. and 15 cm length) with AG1-X8 resin (chloride form, 100–200 mesh) and a flow rate of 1–2 ml/min throughout the separation. 6 M HCl media was used for the adsorption of Cd and Cu on the resin. Then, Cu was eluted by 2 M HCl and Cd by 100 ml 0.5 M HNO₃. The amount of Cu and Cd ions in the final solution (0.5 M HNO₃) were measured by pulse polarographic method and the concentration of Cu was found to be <0.1 ppm. The Cd was quantitatively recovered and the recovery yield from ion-exchange chromatography was greater than 96 %.     

Zirconium silicotungstate matrix as a prospective sorbent material for the preparation of <Superscript>113</Superscript>Sn/<Superscript>113m</Superscript>In generator

The zirconium silicotungstate (ZrSiW) was studied as an effective sorbent material to be used in the ¹¹³Sn/^113mIn generator. The results elucidated that the distribution coefficient of ¹¹³Sn (3700 mL/g) is greater than ^113mIn (275 mL/g) from 0.1 M HCl acid solution to the ZrSiW material. The maximum sorption capacity of Sn (IV) was found to be 33 mg per gram ZrSiW (~?0.3 mmol/g). The elution yield of ^113mIn was found to be >?78?±?6.4% with an acceptable purity of radionuclidic and radiochemical (≥?99.99 and 96.8%, respectively). The rigorous separation of ^113mIn from the ¹²⁵Sb was carried out due to its long half-life (2.758 years) and beta emission that causes tissue damage. Zr, W and Si levels are below the permitted limit in the ^113mIn eluate.     

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.     

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 no-carrier-added 113,117mSn and 113m,114mIn from alpha particle irradiated natural cadmium target

A natural cadmium foil was irradiated by 42 MeV α-particles to produce ^113,117mSn, ^{111,113m,114m}In simultaneously in the target matrix. After the complete decay of short lived radionuclides, long-lived NCA products were separated sequentially from the bulk cadmium by liquid–liquid extraction using di-(2-ethylhexyl)phosphoric acid (HDEHP) dissolved in cyclohexane as organic phase and HCl as aqueous phase. At the optimum condition, 10^?2 M HCl and 5 % HDEHP, NCA In along with NCA Sn radionuclides (75 %) were separated from the bulk Cd resulting to high separation factors of 2.7 × 10⁴ (D _In/D _Cd) and 500 (D _Sn/D _Cd), respectively. The NCA In was stripped back completely to the aqueous phase by 6 M HCl leaving NCA Sn in the HDEHP phase with a separation factor (D _Sn/D _In) of 3.94 × 10⁶.     

<Superscript>137</Superscript>Cs/<Superscript>137m</Superscript>Ba radioisotope generator based on 6-tungstocerate(IV) column matrix

Summary Barium-137m radioisotope generator of the chromatographic column elution mode based on loading 1.5 g 6-tungstocerate(IV) gel matrix with ~54 kBq of fission-produced ¹³⁷Cs is described. The elution performance of the generated ^137mBa radionuclide was investigated as a function of chemical composition of the eluent, flow rate, elution frequency, and age of the generator system. At comparable conditions, ^137mBa eluates with 0.9% NaCl-0.1M HCl eluent had higher elution yields and radionuclidic purity than with 0.1M NH₄Cl-0.1M HCl eluent. The generator has been repeatedly eluted for 311 days by passing 4810 ml of the saline eluent (10 ml × 481 elution operations) at a flow rate of 3.0 ml/min. Barium-137m eluates of high and reproducible elution yields, chemical and radionuclidic purities of (≥ 99.99%) were obtained.     

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.     

Anion-exchange and solvent extraction studies on the separation of radioiodine with particular reference to the production of 123I via proton irradiation of 123Te metal target

The separation of radioiodine was investigated using two wet chemical procedures, namely anion-exchange and solvent extraction. Some factors affecting the separation, such as HCl, NaOH and tetrabutyl ammonium bromide (TBAB) concentrations, used solvents ethyl acetate, benzene and carbon tetrachloride and different quaternary ammonium salts were studied. For each procedure the optimum conditions were deduced. The separation of ¹²³I was effected from proton-irradiated ¹²³Te target under the optimized conditions of the two procedures. The yield of ¹²³I obtained using the Dowex 21k anion-exchanger and tetrabutyl ammonium bromide solution as eluting agent was 88±3%; the radionuclidic purity was high and the time needed was 60 minutes. In solvent extraction process using TBAB in ethyl acetate as the extracting agent, the yield of ¹²³I was low (47±3%), the radionuclidic purity was not as good as in the anion-exchange method, and the time needed was 150 minutes. Therefore, the anionexchange method is preferable. A comparison of this wet chemical method of separation of ¹²³I with the commonly used dry distillation method is given. The wet method appears to be more suitable when a ¹²³Te metal target is used.     

Retention profile and selective separation of 90Y from 89Sr using zirconium-vanadate gel packed column

A low cost and selective method has been developed for the separation of trace concentrations of ⁹⁰Y³⁺ from its parent ⁸⁹Sr²⁺. The proposed procedure is based upon complete retention of ⁹⁰Y³⁺ onto zirconium-vanadate (Zr-V) gel ion exchanger packed column from aqueous solutions containing HCl (1.0 × 10^?5mol dm^?3). Under these conditions, ⁸⁹Sr²⁺ species were not retained onto Zr-V sorbent. The retained ⁹⁰Y³⁺ species were then recovered with HCl. The performance of Zr-V sorbent packed column was determined via the height equivalent to the theoretical plates (HETP) and the number of plates (N). Validation of the developed method was checked by calculating the radionuclidic purity in terms of purification factor (P _f = A/A₀) and radiochemical purity of the eluted ⁹⁰Y from the column. Zr-V sorbent packed column offers unique advantages of retention and quantitative separation of ⁹⁰Y from retention over conventional solid sorbents in rapid and effective separation of trace concentration of ⁹⁰Y³⁺ from ⁸⁹Sr²⁺ in their aqueous equilibrium media.     

Separation of <Superscript>113m</Superscript>In from <Superscript>113</Superscript>Sn based on activated carbon used as column matrix

The activated carbon was prepared by using corncobs and characterized by sorpatometer for using as an exchanger material to separate the generated ^113mIn from ¹¹³Sn and ^124,125Sb. To optimize the separation process, the different parameters like acetone percentage, HCl concentration were studied. The exchange capacity of Sn(IV) is 7.6 meq/g onto the activated carbon and the elution efficiency of ^113mIn > 80% by using 10 mL of 0.2 M HCl-80% acetone with flow rate 1 mL/min. The radionuclidic purity and radiochemical purity of the eluted ^113mIn were examined and clarified the presence of ^124,125Sb with relatively high level as radio impurities, so further separation was carried out by using Dowex 1×8 as an anion exchanger below the activated carbon matrix on the same separation column to adsorb the ¹¹³Sn and ^124,125Sb, which escape from the activated carbon matrix.     

Radiochemical precipitation studies for separation of iodine from tellurium and other trace impurities

Precipitation of radiotellurium, containing trace radioimpurities, has been carried out from sulfate media at different pH-values. The highest precipitation yield was achieved at the region of pH ~4–6. Quantitative uptake by the formed precipitate was noticed for (i) ⁵⁴Mn, ^110mAg and ¹²⁵Sb over all the pH-range of study (pH 1.7–9.2), (ii) for ⁶⁵Zn and ⁶⁰Co in the regions of pH ~6–8 and pH 6–8.8, respectively, and (iii) for ¹³⁴Cs in the region of pH 1.7–2.8, while its percent uptake fluctuated around 60.5 % in the region of pH 4.4–6.4. Further precipitation studies have been conducted for a mixture of ¹²⁵I and radiotellurium from sulfate, nitrate and chloride media at pH-values of 6.0 and 7.5. The highest ¹²⁵I recovery yield in the obtained supernatant was 95.0 ± 1.3 %, which was achieved with sulfate medium at pH 6.0 with percent uptake values of 5.0 ± 1.3, 98.9 ± 0.9 and 62.0 ± 4.6 % of ¹²⁵I, ^123mTe and ¹³⁴Cs, respectively, and quantitative uptake of ⁵⁴Mn, ^110mAg, ¹²⁵Sb, ⁶⁰Co and ⁶⁵Zn by the precipitated tellurium. Thereafter, the supernatant was further acidified with H₂SO₄ and boiled, after adding H₂O₂, for 3 h. >99 % of ¹²⁵I was distilled off from the acidified supernatant. The distilled of ¹²⁵I was received in 0.1 M NaOH + 1 % Na₂S₂O₃ solution, with a radionuclidic purity of >99.99 %, radiochemical purity of >99.8 % as I^? and pH ~13.     

Studies on the production feasibility of 64Cu by (n, p) reactions on Zn targets in Dhruva research reactor

⁶⁴Cu is an useful radionuclide for both PET imaging and targeted therapy, as it decays by three different modes, namely, electron capture (41%), ??^? (40%) and positron emission (19%). ⁶⁴Cu is generally produced by ⁶⁴Ni (p, n) reaction in a cyclotron for medical use. High specific activity ??no carrier added?? grade ⁶⁴Cu by ⁶⁴Zn (n, p) route is an alternative for research studies and was hence explored. 10?mg zinc foil target (48.63% in ⁶⁴Zn) was irradiated in the medium flux reactor Dhruva at a thermal neutron flux of ~5.6?×?10¹³ n?cm^?2?s^?1 for 3?days. The irradiated Zn foil was dissolved in 5?mL 10?M HCl and ⁶⁴Cu was separated by anion exchange chromatography (Dowex 1?×?8; 100?C200 mesh) at 3?M HCl conditions. ⁶⁴Cu radioactivity content and its radionuclide purity were ascertained by ??-ray spectrometry using HPGe detector coupled to a 4?K multichannel analyser system. Radiochemical separation yielded a radionuclidic purity of 99.9% ⁶⁴Cu.     

A109Cd/109mAg generator

Sorption of Cd and Ag by a cation exchange resin has been studied at different molarities of nitric acid. The sorption capacity of Cd on a cation exchanger has been determined. A¹⁰⁹Cd/^109mAg generator is suggested, based on the sorption of Cd on AG 50W-X8 organic cation exchanger at 0.01M HNO₃.^109mAg is eluted with 0.2M NaCl, physiologically compatible for human use.     

Ein Trennverfahren zur Bestimmung von Ag, Cd, Hg und Zn in biologischem Material durch radiochemische Neutronenaktivierungsanalyse

Zusammenfassung Es wurde ein einfaches Trennverfahren für die radiochemische NAA von biologischem Material entwickelt, mit dem aus einem komplexen Nuklidgemisch die Indicator-Radionuklide ^110mAg, ¹⁹⁸Au, ¹¹⁵Cd, ²⁰³Hg und ⁶⁵Zn als eine Gruppe mit Ausbeuten >99% abgetrennt werden können. Besonders geeignet ist dieses Verfahren für die Trennung des ²⁰³Hg von ⁷⁵Se und ⁶⁵Zn von ⁴⁶Sc, die sich bei einer gammaspektrometrischen Messung in der instrumentellen NAA gegenseitig stören. Gleichzeitig können die Nachweisgrenzen für Ag, Au und Cd wesentlich gesteigert werden. Das Verfahren basiert auf dem Aufschluß der bestrahlten Probe in einem Gemisch von HNO₃, HCl und H₂O₂, und auf der Trennung von Ag, Au, Cd, Hg und Zn an Dowex 1X8 aus 1,5 M salzsaurer Probelösung. Die Leistungsfähigkeit dieses Verfahrens wurde an Beispielen der Analyse von Flechten und verschiedenen Pilzarten demonstriert. Bei den verwendeten experimentellen Bedingungen liegen die Nachweisgrenzen in der Größenordnung von 10 ng/g.

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A separation procedure for the determination of Ag, Cd, Hg and Zn in biological material by radiochemical neutron activation analysis

Summary A simple separation procedure for the determination of Ag, Au, Cd, Hg and Zn in biological material by radiochemical neutron activation analysis was developed. It enables the separation of the indicator radionuclides ^110mAg, ¹⁹⁸Au, ¹¹⁵Cd, ²⁰³Hg and ⁶⁵Zn in a group with yields >99% and is well suited for the separation of ²⁰³Hg from ⁷⁵Se and ⁶⁵Zn from ⁴⁶Sc. The separation of these radionuclides is often necessary because of the occurrence of instrumental interferences in the instrumental neutron activation analysis. Simultaneously, the limits of detection for Ag, Au and Cd can significantly be improved. The method is based on the decomposition of the sample in the mixture of HNO₃/HCl/H₂O₂ and on the separation of Ag, Au, Cd, Hg and Zn on Dowex 1X8 from a sample solution being 1.5 M with HCl. The applicability of this method is demonstrated by the analysis of lichens and several kinds of fungi. For the experimental conditions used, the limits of detection are of the order of magnitude of 10 ng/g.