Plutonium removal by ion exchange chromatography

A study of Pu recovery at trace level from U solutions by ion exchange technique is presented. Plutonium retention >99.5% onto strong anionic resin, AG-X8, from nitric acid solutions and a 92% recovery using 0.4M HNO₃ at 60°C as eluent, were obtained. Uranium interference in Pu sorption from mixed U/Pu nitrate solutions with low U/Pu ratio (25) was not verified. However, for high U/Pu ratio solutions (10000), uranium interference in Pu retention on the resin, decreases to 59%. Selecting the loading conditions and using AG-X4 resin, 99% Pu retention was achieved. The Pu product is still contaminated with U and another purification cycle is recomended. A scheme for U/Pu first cycle separation is proposed.     

Direct spectrophotometric analysis of low level Pu(III) in Pu(IV) nitrate of Pu precipitation process feed solution

To achieve end user’s specified PuO₂, controlling and monitoring of Pu in its fourth valency state is essential prior to the conversion of Pu-nitrate to its oxide through oxalate precipitation process. Conventional radiometric procedure for the analysis of Pu oxidation state in Pu-nitrate solution containing trace level of Pu(III) has limitation due to oxidation of Pu(III) during the sample preparation with respect to acidity. A simple direct spectrophotometry using an optic fiber spectrophotometer was attempted for the estimation of trace level of Pu(III), after separating the bulk amount of Pu(IV) by maintaining the sample acidity. By using a synergistic mixture of 30 % TBP and 1 M theonyl trifluoro acetone in benzene, the Pu(IV) could be removed to a level which doesn’t interfere in the Pu(III) absorption.     

A rapid and selective separation of palladium

Palladium was separated from Al, Ru, Rh, U, Pu and also from a mixture of fission products using -benzoin-oxime as the extractant and Solvesso-100 as the diluent. The extraction is quantitative over a wide range of acidity from 0.1M to 4M HNO₃. The method has been found to be equally effective to separate Pd at trace level (carrier-free form). The stoichiometry of the complex, the interference of foreign elements in Pd separation, etc., are reported. The applicability of the method to separate palladium formed in fission rapidly from all other fission products, especially the most strongly interfering molybdenum isotopes, and the recovery of this element from high level radioactive waste are also mentioned.     

Elemental analysis of topaz from northern areas of Pakistan and assessment of induced radioactivity level after neutron irradiation for color induction

To study the impurity elements, which render color-induced topaz long lived radionuclides, three samples of topaz, from three different cities of the Northern Pakistan (Baltistan, Gilgit and Mardan) were analyzed using k ₀ instrumental neutron activation analysis (k ₀-INAA). The samples were irradiated in Pakistan Research Reactor-1 (PARR-1) and PARR-2 at Pakistan Institute of Nuclear Science & Technology (PINSTECH), Islamabad. The method was validated by analyzing IAEA-S7 reference material. In three samples a total of 22 trace level impurity elements were quantified. Among impurities, 10 elements including As, Ce, Ga, Ge, La, Na, Sb, Sc, U and Zn were common in topaz of all the three places. The storage time has been calculated for each sample required to bring the induced radioactivity down to permissible level given by US National Regulatory Commission.     

One step U-Pu-Cs-Ln-steel separation using TRU preconditioned extraction resins from Eichrom for application on transmutation targets

A one step Cs, lanthanides (Ln), Pu and U separation using TRU resin (Eichrom), for subsequent isotopic analyses, is presented for samples of transmutation targets containing a predominant matrix of steel elements. Cs, Ln, Pu and U are successively eluted using minor volumes (<12 mL) of 2M HNO₃, 4M HCl, 0.075M oxalic acid in 1M HCl media and 0.1M ammonium hydrogen oxalate in 0.02M HNO₃ media, respectively. Accurate and precise isotopic compositions obtained for these elements by thermal ionization mass spectrometry or multiple collector inductively coupled mass spectrometry show neither significant fractionation nor contamination during the complete analytical process.     

Rapid Separation of Plutonium in Environmental Samples Using an Anion Exchange Resin Disk

A rapid analytical method of Pu in environmental samples by alpha-ray spectrometry and high-resolution inductively coupled plasma mass spectrometer (HR-ICP-MS) using a 3M Empore anion exchange resin disk for solid phase extraction has been developed. A trace amount of Pu was quantitatively adsorbed with an Empore anion exchange resin disk (47 mm diam.) at a flow rate of 150–200 ml/min from 8M HNO₃ sample solution. The disk was washed with 10 ml of 8M HNO₃ and 12 ml of 9M HCl and then the Pu was quantitatively eluted with 15 ml of 1M HNO₃/0.03M ascorbic acid solution. The time needed to separate Pu from the sample solution with the present method was about 20 minutes. The separated Pu was determined with alpha-ray spectrometry and HR-ICP-MS. The present method was applied to the determination of Pu in the certified reference material (IAEA-135) and the environmental soil sample. The analytical results were almost in good agreement with the literature values.     

Determination of trace impurities in tantalum powder and its compounds by inductively coupled plasma optical emission spectrometry using solvent extraction

A procedure was developed for the analysis of 18 trace impurity elements in capacitor-grade tantalum powder (Ta), potassium tantalum fluoride (K₂TaF₇), and tantalum pentoxide (Ta₂O₅) using inductively coupled plasma optical emission spectrometry (ICP-OES). The detection limits achieved were in the ppb levels. The samples were dissolved in hydrofluoric acid (HF) in a microwave digestion system and the Ta matrix was extracted using cyclo hexanone. The impurity traces remained almost completely in the aqueous phase. The text was submitted by the authors in English.     

Preconcentration Atomic Absorption Spectrophotometric Determination of Trace Lead(II) by Hydride Generation Combined with an Adsorbent Water Suspension Sampling Technique

The optimization of preconcentration atomic absorption spectrophotometric determination of trace lead(II) has been studied by using hydride generation and adsorbent water suspension sampling techniques. The uptake of lead(II) by a specially adapted chelate-forming resin, that is, a sulfonated dithizone (DzS)-loaded resin, was complete in the pH range 6.3-10. Lead adsorbed on DzS-loaded resin was successfully converted into its hydride in a medium, HCI --- H₂O₂ --- NaBH₄ without the need for a desorption procedure. Chelating agents except for DzS and DzS-loaded resin interfered seriously with the generation of lead hydride. Severe interference from diverse hydride-forming elements and transition metal ions is eliminated to a great extent by the treatment with DzS-loaded resin. The calibration curve obtained from the lead-bearing resin-water suspension was linear in the range of 5-500 ng/ml, whereas that from aqueous standard solution was in the range of 5-200 ng/ml. The detection limit of the method depends on the concentration factor and is 0.025 ng/ml in the present study. The proposed method was applied to the determination of trace lead(II) in environmental water samples.     

Determination of impurities in niobium metal by a radiochemical neutron activation analysis

A radiochemical separation method using an anion exchange resin has been applied to 3N grade Nb for determining nine impurity elements. Five elements (Cr, Fe, Co, Zn and Se) were separated in 2M HF, three elements (Mo, W and Hf) in 32M HF, Nb in 0.5M HF/3M HCl, and Ta in 1M NH₄F/4M NH₄CCl. The contents of the elements were calculated by a single comparator method using two monitors of Au and Co. The main impurity was revealed to be Ta with a content of over 160 ppm.     

聚乙烯乙二胺丙酰胺肟大孔螯合树脂的合成及其富集分离微量元素的应用研究

本文以大孔聚氯乙烯树脂为原料,合成聚乙烯乙二胺丙酰胺肟螯合树脂,建立了利用该螯合树脂富集分离20余种微量元素的ICP化学光谱法,讨论了其富集各待测元素的性能和机理,进行了螯合树脂的红外光谱等结构分析及样品中微量元素的富集和测定,结果较满意。     

Synthesis of chitosan resin possessing 3,4-diamino benzoic acid moiety for the collection/concentration of arsenic and selenium in water samples and their measurement by inductively coupled plasma-mass spectrometry

A chitosan resin functionalized with 3,4-diamino benzoic acid (CCTS-DBA resin) was newly synthesized by using a cross-linked chitosan (CCTS) as base material. The adsorption behavior of trace amounts of elements on the CCTS-DBA resin was examined by the pretreatment with a mini-column and measurement of the elements by inductively coupled plasma-Mass spectrometry (ICP-MS). Arsenic(V) could be retained on the CCTS-DBA resin at pH 3 as an oxoanion of H₂AsO₄⁻. Selenium(VI) is strongly adsorbed at pH 2 and pH 3 as an oxoanion of SeO₄²⁻, while selenium(IV) as HSeO₃⁻ is adsorbed on the resin at pH 3. The sorption capacities are 82, 64, and 88 mg g⁻¹resin for As(V), Se(IV), and Se(VI), respectively. The effect of common anions and cations on the adsorption of As(V), Se(IV), and Se(VI) were studied; there was no interference from such anionic matrices as chloride, sulfate, phosphate, and nitrate up to 20 ppm, as well as from such artificial river water matrices as Na, K, Mg, and Ca after passing samples through the mini-column containing the resin. The CCTS-DBA resin was applied to the collection of arsenic and selenium species in bottled drinking water, tap water, and river water.     

Determination of neptunium in plutonium materials by ICP-MS

An ICP-MS analytical method as an alternative to the current radiochemical method was developed to analyze trace level ²³⁷Np in bulk plutonium materials. In this method, ²³⁷Np is determined together with a suite of trace elements during a single analysis using one dissolution solution. Method validation was achieved through precision examination, spike recovery study, detection limit determination, comparison of results with the radiochemical method, and laboratory intercomparison studies on Pu metals. The ICP-MS method significantly reduced the analysis cost, the sample amount, consumption of chemicals and waste generation, as well as the sample turnaround time.     

Direct determination of trace metals in solid samples by atomic absorption spectrometry with electrothermal atomizers: Part 4. Interference effects in the determination of lead and bismuth in steels

The origin of observed interference effects is investigated by comparing signals obtained for lead and bismuth before and after the addition of different matrix components. It is concluded that the applicability of the solid-sampling technique should be related to the solubility of the impurity in the matrix components and to the volatilities of the impurity and matrix. The extent to which trace elements are removed from steels is similarly established by using steels and graphite pieces to which the element was added. The samples are introduced under isothermal conditions and peak areas are evaluated. It is found that 80% of lead or bismuth is recovered from stainless steel at 2100°C. Thus standardization against aqueous solutions gives inaccurate results for solid samples.     

Americium and plutonium separation by extraction chromatography for determination by accelerator mass spectrometry

A simple method was developed to separate Pu and Am using single column extraction chromatography employing N,N,N′,N′-tetra-n-octyldiglycolamide (DGA) resin. Isotope dilution measurements of Am and Pu were performed using accelerator mass spectrometry (AMS) and alpha spectrometry. For maximum adsorption Pu was stabilized in the tetra valent oxidation state in 8 M HNO₃ with 0.05 M NaNO₂ before loading the sample onto the resin. Am(III) was adsorbed also onto the resin from concentrated HNO₃, and desorbed with 0.1 M HCl while keeping the Pu adsorbed. The on-column reduction of Pu(IV) to Pu(III) with 0.02 M TiCl₃ facilitated the complete desorption of Pu. Interferences (e.g. Ca²⁺, Fe³⁺) were washed off from the resin bed with excess HNO₃. Using NdF_3, micro-precipitates of the separated isotopes were prepared for analysis by both AMS and alpha spectrometry. The recovery was 97.7 ± 5.3% and 95.5 ± 4.6% for ²⁴¹Am and ²⁴²Pu respectively in reagents without a matrix. The recoveries of the same isotopes were 99.1 ± 6.0 and 96.8 ± 5.3% respectively in garden soil. The robustness of the method was validated using certified reference materials (IAEA 384 and IAEA 385). The measurements agree with the certified values over a range of about 1–100 Bq kg⁻¹. The single column separation of Pu and Am saves reagents, separation time, and cost.     

Recovery of americium from analytical solid waste containing large amounts of uranium,plutonium and silver

Trace metallic impurity analysis by spectroscopic techniques is one of the important steps of chemical quality control of nuclear fuel materials. Depending on the burn-up and the storage time of the fuel, there is an accumulation of ²⁴¹Am in plutonium based fuel materials due to β decay of ²⁴¹Pu. In this paper, attempts were made to develop a method for separation of ²⁴¹Am from 1.2 kg of analytical solid waste containing 70% U, 23% Pu, 5% Ag and 1–2% C as major constituents along with other minor constituents generated during trace metal assay of plutonium based fuel samples by d. c. arc carrier distillation atomic emission spectrometry. A combination of ion exchange, solvent extraction and precipitation methods were carried out to separate ~45 mg of ²⁴¹Am as Am(NO₃)₃ from 15 L of the analytical waste solution. Dowex 1×4 ion exchange chromatographic method was used for separation of Pu whereas 30% TBP–kerosene was utilized for separation of U. Am was separated from other impurities by fluoride precipitation followed by conversion to nitrate. The recovery of Pu from ion exchange chromatographic separation step was ~93% while the cumulative recovery of Am after separation process was found to be ~90%.     

Determination of analytes at trace level in uranium matrix by ICP-AES without chemical/physical separation

Determination of trace metallic constituents in nuclear materials e.g. U, Pu, Am, Zr etc. by Atomic Emission Spectroscopy requires the separation of the major matrix without the loss of analytes at trace level. For DC Arc carrier distillation technique, carrier is used to separate the matrix physically according to the volatility of the analytes while appropriate extractant in suitable diluent is used for chemical separation in inductively coupled plasma atomic emission spectroscopy (ICP-AES). In the present study an attempt was made to develop a methodology for the determination of B, Cd, Mg, Zn, Al, Sr and Sc at trace level (up to 0.1 μg/mL) in uranium matrix without any chemical or physical separation. It involves identification of suitable analytical lines of uranium for its ICP-AES determination; study the spectral interference of uranium to choose interference free analytical lines, optimization of instrumental and experimental parameters etc. The method was validated using synthetic samples.     

Determination of trace amounts of plutonium in low-active liquid wastes from spent nuclear-fuel reprocessing plants by flow injection-based solid-phase extraction/electrochemical detection system

A flow injection-based electrochemical detection system coupled to a solid-phase extraction column was developed for the determination of trace amounts of plutonium in low-active liquid wastes from spent nuclear-fuel reprocessing plants. The oxidation state of plutonium in a sample solution was adjusted to Pu(VI) by the addition of silver(II) oxide. A sample solution was made up in 3 mol L^?1 HNO₃ and loaded onto a column packed with UTEVA^® with 3 mol L^?1 HNO₃ as the carrier. Plutonium(VI) was adsorbed onto the resin, and interfering elements were removed by rinsing the column with 3 mol L^?1 HNO₃. Subsequently, the adsorbed Pu(VI) was eluted with 0.01 mol L^?1 HNO₃, and then introduced directly into the flow-through electrolysis cell with boron-doped diamond electrode. The eluted Pu(VI) was detected by an electrochemical amperometric method at a working potential of 0.1 V (vs. Ag/AgCl). The current produced on reduction of Pu(VI) was continuously monitored and recorded. The plutonium concentration was calculated from the relationship between the peak area and concentration of plutonium. The relative standard deviation of ten analyses was 1.1% for a plutonium solution of 25 μg L^?1 containing 50 ng of Pu. The detection limit calculated from three-times the standard deviation was 0.82 μg L^?1 (1.6 ng of Pu).     

Application of iminodiacetate chelating resin muromac A-1 in on-line preconcentration and inductively coupled plasma optical emission spectroscopy determination of trace elements in natural waters

On-line system incorporating a microcolumn of Muromac A-1 resin was used for the developing of method for preconcentration of trace elements followed by inductively coupled plasma (ICP) atomic emission spectrometry determination. A chelating type ion exchange resin has been characterized regarding the sorption and subsequent elution of 24 elements, aiming to their preconcentration from water samples of different origins. The effect of column conditioning, pH and flow rate during the preconcentration step, and the nature of the acid medium employed for desorption of the retained elements were investigated. A sample (pH 5) is pumped through the column at 3 ml min⁻¹ and sequentially eluted directly to the ICP with 3 M HNO₃/HCl mixtures. In order to remove residual matrix elements from the column after sample loading a short buffer wash was found to be necessary. The effectiveness of the matrix separation process was illustrated. The procedure was validated by analyzing several simple matrices, Standard River water sample as well as artificial seawater. Proposed method can be applied for simultaneous determination of In, Tl, Ti, Y, Cd, Co, Cu and Ni in seawater and for multielement trace analysis of river water. Recovery at 1 μg l⁻¹ level for the determination of investigated 24 elements in pure water ranged from 93.1 to 96% except for Pd (82.2%) and Pb (88.1%). For the same concentration level for seawater analysis recovery was between 81.9 and 95.6% except for Hg (38.2%).     

Synthesis of novel chitosan resin derivatized with serine diacetic acid moiety and its application to on-line collection/concentration of trace elements and their determination using inductively coupled plasma-atomic emission spectrometry

A novel chelating resin functionalized with serine diacetic acid moiety was synthesized by using chitosan as base material, and applied to the collection/concentration of trace elements in environmental water samples, followed by the determination using inductively coupled plasma-atomic emission spectrometer (ICP-AES). The synthesized resin, crosslinked chitosan serine diacetic acid (CCTS-SDA), showed good adsorption behavior toward trace amounts of Cd, Pb, Cu, Ni, V, Ga, Sc, In, and Th in a wide pH range. Additionally, rare earth elements also can be retained on the resin at neutral pH region. The adsorbed elements can be easily eluted with 1 mol L⁻¹ of nitric acid, and their recoveries were found to be 90-100%. The CCTS-SDA was packed in a mini-column, which was then installed in a computer-controlled auto-pretreatment system (Auto-Pret System) for on-line trace elements collection and determination with ICP-AES. Experimental parameters which related to the improvement of sensitivity and reproducibility were optimized. The limits of detection (LOD) for 13 elements were found to be in sub-ppb level. The proposed method with CCTS-SDA resin was successfully applied to the determination of trace elements in river water samples. The method was validated by determining a certified reference material of river water, SLRS-4.     

Development of rapid plutonium analysis for environmental samples by isotope dilution/inductively coupled plasma mass spectrometry with on-line column.

This paper describes our development of a rapid on-line column/ID-ICP-MS technique for the analysis of plutonium (Pu) in environmental samples using an UTEVA extraction chromatograph resin (UTEVA resin) column. It took only 40 min to separate and measure Pu in the sample solution, including the time for conditioning the resin column for the next analysis. In our method, Pu in a 3 M nitric acid solution was fed to the UTEVA resin, and then eluted from the resin by reducing Pu to Pu(III) with 3 M nitric acid mixed with 0.01 M ascorbic acid after washing the resin. The outflow from the resin column was directly introduced to an ICP-MS system. The low concentration of ascorbic acid and the small volume of the eluting solution (0.6 mL) made successive stable analysis possible without any skimmer cone clogging. The chemical recovery of Pu during column operation was 70%, and typical lower detection limits for 239Pu, 240Pu and 242Pu were 9.2, 4.3 and 7.5 fg (21, 36 and 1.1 microBq), respectively. We analyzed five international standard materials for Pu, and obtained good results.