Evaluation of New Anion Exchange Resins for Plutonium Processing

Abstract

This paper presents the results of studies comparing the performance of two new anion exchange resins for plutonium processing with the well proven and widely used benchmark, Dowex 1X4 resin. In this connection, the experiments on distribution ratio measurement of plutonium as a function of nitric acid concentration, Pu(IV) sorption kinetics, chemical, thermal, and radiation degradation of the two commercially available anion exchange resins namely, Tulsion A‐PSL 4 and Tulsion A‐PSL 6 have been studied, vis‐à‐vis the benchmark. Tulsion A‐PSL 6 was found to have higher plutonium sorption capacity and polymer matrix stability as well as better kinetics of sorption than the other two resins, while Tulsion A‐PSL 4 and Dowex 1X4 were found to have comparable sorption capacity, kinetics, and resistance to chemical and radiation degradation. The small‐scale evaluation of these new anion exchange resins shows that they can be used for the purification and concentration of plutonium.     

A Model Predicting Equilibrium for Plutonium Sorption by Anion Exchange Resin

A mathematical model is derived for prediction of equilibrium between plutonium in aqueous solution and plutonium sorbed on anion exchange resin. The model is analogous to the Langmuir (BET Type I) model for adsorption. Sorption kinetics are modeled as a first order reaction with respect to the plutonium and the resin sorption site concentrations. The model predictions are correlated to previously reported experimental equilibrium data over a range of plutonium concentration from 0.0029 to 300 g Pu/L. Plutonium content of the resin pores is shown to be a significant portion of the total resin phase plutonium. Two methods are described for calculating resin porosity from experimental equilibrium data. The porosity of Dowex-1x4 resin in 7M nitric acid is calculated to be 5 to 8 vol% at high plutonium sorption. Maximum sorption capacity of the resin for plutonium is calculated to be from 87 to 93% of the stoichiometric capacity for a divalent anion.     

Synthesis,Characterization, and Evaluation of Gel‐Type Poly(4‐Vinylpyridine) Resins for Plutonium Sorption

Abstract

Three different cross‐linked (4, 8, and 12%) gel‐type strong‐base poly(4‐vinylpyridine) resins (PVP) have been synthesized and characterized by elemental analysis, IR, exchange capacity, and moisture content. The uptake of plutonium and uranium was measured as a function of nitric acid concentration using all the three PVP resins. Plutonium sorption and elution kinetics experiments were also performed on all three PVP resins and compared with the benchmark, a gel‐type quarternary ammonium type anion‐exchange resin. The plutonium sorption rate decreases with the increase in cross‐linkage of the resin. All the three PVP resins exhibit better elution kinetics compared to the benchmark. The results on kinetic experiments performed on all three‐gel‐type resins indicated 8% gel‐type PVP resin with 50–100 mesh as a better candidate for plutonium processing or purification. Radiation degradation studies were carried out on the 8% PVP resin by gamma irradiation up to 200 MRad. The irradiated resins were characterized by IR, TGA, and SEM.

The exchange capacity, moisture content, and plutonium uptake were also evaluated for the irradiated PVP resins in comparison with the benchmark. The results indicated a better radiation stability for PVP resin over the benchmark.     

Studies on the Sorption of Palladium using Cross‐Linked Poly (4‐Vinylpyridine‐Divinylbenzene) Resins in Nitric Acid Medium

Various cross‐linked (4, 8, and 12%) gel‐type weak‐base poly(4‐vinylpyridine) (PVP) resins were studied for palladium recovery from nitric acid medium. The sorption of palladium was found to decrease with an increase in cross‐linkage of the resin. 8 and 12% PVP resins exhibited maximum D _Pd(II) values at 2–6 M HNO₃, whereas 4% PVP resin showed maximum D _Pd(II) values at lower acidities (0.1 M HNO₃). FT‐IR, SEM, and XPS techniques were used for the characterization of palladium‐loaded resins. Detailed studies were carried out with the resin of modest cross‐linkage i.e., 8% PVP resin. The sorption isotherm studies revealed that the maximum palladium loading approaches the theoretical capacity of the resin, presuming the sorption of palladium as divalent anion at 4 M HNO₃. The pseudo‐second order kinetics model yielded the best fit for the experimental data of sorption kinetics. An increase in temperature accelerates the rate of palladium extraction and also the addition of chloride ions increases the palladium uptake. Column studies were performed using 4 and 8% PVP resins in 2 and 4 M nitric acid concentrations. The loaded palladium could be eluted efficiently with acidic thiourea solution.     

UPTAKE OF METAL IONS BY A NEW CHELATING ION EXCHANGE RESIN. PART 8 : SIMULTANEOUS UPTAKE OF CATIONIC AND ANIONIC SPECIES* *

ABSTRACT

The uptake of tri-, tetra- and hexa-valent actinides as well as of pertechnetate anions by some new multifunctional ion exchange resins has been investigated. The new resins, identified as Diphonix A, for anionic Diphonix, contain the same geminally substituted diphosphonic acid groups bonded to a styrenic-based polymer matrix as the regular Diphonix resin, plus strong base anion exchange groups such as the tetraalkylammonium (Diphonix A - Type 1 resins) or the quaternized pyridinium (Diphonix A - Type 2 resins) groups. Our uptake measurements have shown that the Type 2 Diphonix A resins are as effective as the regular Diphonix resin in the rapid uptake of actinides from acidic solutions, while at the same time sorbing pertechnetate anions in a manner comparable to existing commercial anion exchange resins. The failure of the Type 1 Diphonix A resins to perform equally well has been explained as a consequence of the mutual interaction of adjacent diphosphonic acid groups and tetraalkylammonium groups. Uptake data have also been obtained with Se(IV). The behavior of the Diphonix A resins toward Se(IV) uptake in acidic solutions is comparable to that of commercial anion exchange resins.     

EXTRACTION OF PLUTONIUM BY CHELATING HYDROXYPYRIDINONE AND CATECHOLAMIDE RESINS∗

ABSTRACT

Four new chelating hydroxypyridinone and catecholamide polystyrene-supported extractants have been prepared and evaluated for their ability to selectively remove ppm levels of plutonium from a variety of acidic aqueous waste compositions. The hydroxypyridinone and catecholamide ligands, modeled after the metal ion binding sites found in siderophores, were derivatized to allow covalent attachment to a polymeric support. The synthesis, loading capacities and chemical stability of the new resins are reported along with the results from extraction studies evaluating their performance for the extraction of Pu(IV) and Pu(VI) from a variety of HNO₃ and NaN0₃ solutions up to 5 M and in competition with Fe(III), Al(III), Zr(IV) and EDTA. The kinetics of metal ion sorption onto the resins are fast, and the extraction results are compared to the commercial Chelex resin.     

Ion‐Exchange Separation of Pu from Macro Concentration of Th in HNO3 Medium

Abstract

Sorption behavior of Th and Pu from anion‐ as well as cation‐exchange resin was investigated from nitric acid medium by both batch and column methods. The anion‐exchange studies involved anionic nitrate complexes of Pu⁴⁺ and Th⁴⁺ sorbed onto DOWEX 1x4 resin (50–100 mesh), and the cation‐exchange studies involved the sorption of Pu³⁺ and Th⁴⁺ onto BIORAD AG 50Wx8 (50–100 mesh) or DOWEX 50Wx4 (50–100 mesh) resin. The batch data gave a separation factor (K _d,Pu/K _d,Th) of 22 for the anion‐exchange method and 0.017 for the cation‐exchange method at 3 and 2 M HNO₃, respectively. A two‐stage ion‐exchange separation method was developed for the quantitative separation of Pu (8 g/L) from a macro amount of Th (200 g/L) in nitric acid medium. The first step involved the quantitative sorption of plutonium from the mixture while about 90% of Th could be washed in 6 column volumes. The plutonium, eluted (as Pu³⁺) using 0.5 M HNO₃ + 0.2 M hydrazinium nitrate (HN) + 0.2 M hydroxyl ammonium nitrate (HAN), and the residual (～10%) Th were subsequently loaded onto a cation‐exchange column in the second step. Greater than 99% Pu was recovered with 2 M HNO₃ (in ～8 column volumes) containing 0.2 M HN + 0.2 M HAN. The final elution of thorium from the cation‐exchange column was achieved in about 6 column volumes of 1 M α‐hydroxy isobutyric acid. A (Pu, Th)O₂ fuel scrap sample was dissolved in 16 M HNO₃ containing 0.005 M HF and was used subsequently as the feed for the anion‐exchange column. The eluted Pu was subsequently loaded onto a cation‐exchange column for final purification. The recovery of plutonium and thorium was found to be >99% and >98%, respectively, while the respective decontamination factors were estimated to be 215 and 292.     

Sorption Behavior of Dowex PSR-2 and Dowex PSR-3 Resins of Different Structures for Metal(II) Removal

The sorption behavior of palladium(II) (Pd(II)) onto strongly basic anion exchange Dowex resins was studied depending on the concentration of hydrochloric acid (0.1–6.0 M HCl–100 mg Pd(II)/L), concentration of hydrochloric and nitric(V) acids (0.1–0.9 M HCl–0.9–0.1 M HNO₃–100 mg Pd(II)/L), and the time of contact of the solution with the anion exchange resin in the batch mode. Similar research was carried out also for the base metal ions such as cobalt(II) (Co(II)), copper(II) (Cu(II)), nickel(II) (Ni(II)), and zinc(II) (Zn(II)). The sorption process was also examined depending on the initial Pd(II) concentration, agitation rate, bead size distribution, and temperature. Pd(II) sorption was also checked in the column mode. The equilibrium and kinetic characteristics of the sorption of Pd(II) with the Dowex PSR-2 and Dowex PSR-3 anion exchange resins were determined. The possibilities of Pd(II) elution and reuse using the batch method was exploited. Pd(II) and Zn(II) sorption on the Dowex resins is time and concentration of acids dependent. Evaluating the determination coefficients, the kinetic studies showed that the pseudo-second-order equation and the Langmuir model described the data more appropriately than others. The maximum sorption capacity was 165.15 mg Pd(II)/g for Dowex PSR-2 and 184.39 mg Pd(II)/g for Dowex PSR-3. Dowex resins give quantitative Pd(II) removal from diluted acidic solutions.     

Introduction of bifunctionality into the phosphinic acid ion-exchange resin for enhancing metal ion complexation

In nuclear industry the role of conventional strong cation exchange resins is limited as they function less in high acid media. The phosphorous group that has got more affinity towards actinide elements is chosen as a chelating group and the phosphinic acid ion exchange resin was synthesized. The extraction ability of the phosphinic acid resin for plutonium (Pu) from HNO₃ medium as well as from H₂SO₄ medium was studied. Though the resin shows better extraction for Pu than the strong cation exchanger resins at higher acidities, its kinetics is slow. In order to enhance the kinetics as well as to improve upon selectivity, a sulphonic group is introduced into the phosphinic acid resin. To verify the effect of bifunctionality extraction studies have been carried out with Pu from different acid media of varying concentrations. Sulphonated phosphinic acid resin shows a 2-fold increase in distribution coefficient (k_d) as well as it reached equilibrium very fast compared to the phosphinic acid resin. It is postulated that the sulphonic acid ligand provides an access mechanism for the metal ions into the polymer matrix while it is the phosphinic acid group that is responsible for selective coordination of metal ions. Thus bifunctionality is coupling of an access mechanism to a recognition mechanism. The experiments carried out demonstrated the applicability of sulphonated phosphinic acid resin in the nuclear industry.     

Piperazine Functionalized Resins for Au(III), Pt(IV), and Pd(II) Sorption

The result of synthesis of anion exchangers bearing piperazine functionalities is presented in this paper. A series of new ion exchange resins was synthesized by modification of VBC/DVB copolymer with 1(2-aminoethyl)piperazine (resin 1P), 1-amino-4-methylpiperazine (resin 2P), and 1-methylpiperazine (resin 3P). Adsorption studies of gold, platinum, and palladium were conducted with batch and dynamic method from multicomponent solutions containing AuCl₄^?, PtCl₆^2?, and PdCl₄^2? in the concentration range 10 mg/dm³ to 919 mg/dm³. The resins revealed excellent sorption ability towards these metals. The greatest total sorption capacities were determined as 331 mg/g Au for 2P resin, 405 mg/g Pt for 3P resin, and 150 mg/g Pd for 1P resin. The examined 3P resin showed the best total sorption capacity 796 mg/g. Affinity studies were also conducted. The examined resin 1P revealed the greatest affinity to platinum and palladium (lgK 4.5-5) whereas resin 2P revealed the best affinity to gold where lgK were ca. 4.9.     

Effect of gamma irradiation on the metal sorption and separation of some divalent metals by some new polymeric bifunctional resins

The metal sorption and separation of some divalent metals from solutions of varying acidity by a new series of gamma-irradiated ionic polymer resins have been investigated. Three polymeric resins, viz., phosphonic acid, phosphonate monoethyl ester, and phosphonate diethyl/monoethyl ester, were used in this study. The results of metal sorption and separation were compared with those of the well-known cation exchange resin Dowex X8. The results were correlated in the usual manner of distribution coefficients (D) of three divalent metals Sr(II), Co(II), and Ni(II). The results of metal sorption by the ionic resins under investigation compared with that of sulfonic acid resin, showed that Ni showed the highest affinity for the unirradiated monoethyl ester/phosphonic acid resin, while Sr showed the highest affinity for phosphonic acid resin and Co showed the highest affinity for mono/diethyl ester phosphonic acid resin. Moreover, the three metals (Sr, Co, Ni) showed the lowest affinity toward sulfonic acid resin. The calculated separation factors for the different resins indicate that the unirradiated phosphonic acid resin has the highest capacity to separate Sr from Ni, whereas mono/diethyl ester/phosphonic acid resins have the highest capacity to separate Co from Sr and Ni. Furthermore, the affinity of the ionic polymers for the metal ions was not greatly changed after gamma irradiation. © 1997 John Wiley & Sons, Inc. J Appl Polm Sci 65:1091–1101, 1997     

CYPHOS IL 101 (Tetradecyl(Trihexyl)Phosphonium Chloride) Immobilized in Biopolymer Capsules for Hg(II) Recovery from HCl Solutions

Abstract

A composite polymer (made of gelatin and alginate) was used for the synthesis of Cyphos IL 101-immobilized resins. These resins (with varying size and different ionic liquid (IL) content) have been tested for the recovery of mercury from concentrated HCl solutions (0.1–5 M HCl concentrations). Prior to the study of sorption performance on resins, the reactivity of Cyphos IL 101 versus mercury was tested using solvent extraction methodology. These results showed that the extraction was hardly affected by the concentration of HCl and that an ion exchange mechanism was probably involved in metal recovery (binding of HgCl₄ ^2-). The performance of these resins for Hg(II) recovery was tested through sorption isotherms and uptake kinetics, investigating the effect of resin size, ionic liquid content, metal concentration, agitation speed, and resin state (dry state versus wet state). Sorption capacity (which was proportional to the IL content) can reached up to 150 mg Hg g^?1 in 1 M HCl; this sorption capacity was decreased by increasing chloride concentration. The kinetics were described well by the pseudo-second order equation and by the intraparticle diffusion equation (the so-called Crank's equation). The intraparticle diffusion coefficient was in the range of 10^?11–1.2 × 10^?10 m² min^?1. The kinetic profiles were controlled by the IL content, sorbent dosage, and the sorbent particle size. Drying of the resins significantly decreased diffusion rates in the resins. The presence of competitor metals did not affect sorption capacity except when stable chloro-anionic species such as in the case of Zn(II) were formed. Mercury can be desorbed using 6 M nitric acid solutions; and the sorbent can be recycled for at least six sorption/desorption cycles without significant decrease in the sorption performance.     

Parametric studies on the synthesis of amidoximated adsorbent resins

The main goal of this study was to obtain acrylonitrile (AN)‐divinylbenzene (DVB) copolymer beads that can serve as the matrix for preparation of amidoxime resins. AN‐DVB amidoxime resin was synthesized via suspension polymerization and the effect of different parameters such as the speed of stirrer, the amounts of suspending agent, hydrophilic agent, diluent agent, and initiator on its properties was investigated by fractional factorial (Taguchi) experimental design method. This method gives much‐reduced variance for the experiments with optimum control parameters setting and provides a set of minimum experiments compared to the conventional methods. The results showed that the most effective parameters on the amidoximation of resins were hydrophilic agent content, speed of stirrer, and the amount of suspending agent, respectively. Furthermore, anion‐exchange capacity of the amidoxime resins was utilized as a criterion for the evaluation of amidoxime adsorbent groups and the adsorption potential of the synthesized resins was determined by cation‐exchange capacity. The amount of methylacrylate as a hydrophilic agent had the most significant effect on the ion‐exchange capacity of the final product. Swelling ratio was also measured to evaluate the adsorption capacity of the synthesized resin. The results showed that the amounts of hydrophilic and diluent agents had significant effects on swelling ratio of resin. Finally, cation‐exchange capacity and swelling ratio of amidoxime resin were changed greatly because of alkaline treatment, but it had no significant effect on the anion‐exchange capacity of the synthesized resin. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Polyacrylate Ion Exchangers in Sorption of Noble and Base Metal Ions from Single and Tertiary Component Solutions

Two polyacrylic resins of different types such as Purolite S-984 (macroporous, chelating with a polyacrylic matrix supporting functional groups of the polyamine type) and Amberlite IRA-478RF (gel, intermediate polyacrylic anion exchanger with the tertiary amine and quaternary ammonium functional groups) were applied in removal of palladium(II) metal ions from HCl and HCl – HNO₃ solutions. Its sorption behaviors for base (Co(II), Ni(II), Cu(II), Ni(II)) and other noble metal (Pt(IV), Au(III)) ions, kinetics, and equilibrium studies were carried out in detail. The obtained results indicate that the resin is characterized by high sorption capacity and good kinetics of the sorption process. For the elution, the solutions of various reagents, that is, HCl, HNO₃, H₂SO₄, NaOH, NH₄OH, (NH₂)₂CS were studied as regards the complete release of the metal ions retained by the resin. Gold(III) could be eluted quantitatively from the loaded resin whereas Pd(II) and Pt(IV) could not by means of the applied eluting agent.     

Selective Separation of Uranium using Alizarin Red S (ARS)-Modified Anion-Exchange Resin or by Flotation of U-ARS Chelate

ABSTRACT

An alizarin red S (ARS)-modified anion-exchange resin was prepared by a simple reaction of ARS with the anion exchanger Doulite A101 and used for the efficient sorption of uranium from aqueous media. The effect of various parameters on the sorption of U(VI) (pH effect, sorption kinetics, resin capacity and breakthrough curves) was investigated. The modified resin sorbs U(VI) over a wide range of pH (2·8–5) with a maximum sorption capacity of 0·68 mmol.g^?1 at pH 3·2 to 4·0. Iron (III), Zr(IV), Ti(IV), Cu(II), and Th(IV) ions are also sorbed to different extents, but Be(II), Bi(III), Ca(II), Mg(II), Pb(II), Hg(II), Zn(II), Cd(II), AI(III), Mn(II), Co(II) and Ni(II) are not sorbed; thus, conditions for separating U(VI) from these metal ions have been identified. For eluting U(VI) from the resin, 0·2 mol.L^?1 HCl was used and the recovery recorded was as high as 99.9%. The use of ARS is extended to float uranium quantitatively and selectively from aqueous media at pH = 4 by using oleic acid as a surfactant. The different parameters affecting the flotation process have also been investigated. Uranium(VI) has been effectively separated from natural water samples and certified uranium ores using both procedures.     

UPTAKE OF METAL IONS BY A NEW CHELATING ION-EXCHANGE RESIN. PART 1: ACID DEPENDENCIES OF ACTINIDE IONS*

ABSTRACT

The uptake of several actinide ions [U(VI), Pu(IV), Np(IV), Th(IV] and Am(DI)) from nitric and hydrochloric acid solutions, and of U(VI) from near-neutral solutions by the new chelating ion-exchange resin, Diphonix^TM, has been investigated. Diphonix is a polyfunctional resin containing sulfonic and gem-diphosphonic acid groups chemically bonded in a styrene-divinylbenzene polymeric network. Comparison of the acid dependencies of the actinide ions uptake measured with Diphonix with those obtained using a commercial sulfonic -type resin and a resin containing both sulfonic and monophosphonic aCid groups, hat Shown that Diphonix binds the actinides via a different kind of chemical interaction, involving the.formation of chelate complexes through the phosphoryl groups of the gem-diphosphonic acids. As a consequence, Diphonix is superior to other resins in extracting actinide ions from very acidic solutions. A better performance of Diphonix is also observed with the uptake of uranium from neutral solutions. Conditions for efficient stripping of actinide species from the resin have been found.     

Treatment of wastewater containing Pb and Fe using ion‐exchange techniques

Treatment of wastewater containing lead and iron was examined using two different ion‐exchange resins namely Duolite ES 467 (containing amino‐phosphonic functional groups) and a chelating ion‐exchange resin (containing hydroxamic acid functional groups). Initially different sorption parameters such as contact time, pH, concentrations of sorbent, sorbate and chloride ion were studied. The sorption kinetics was observed to be fast and equilibrium could be reached within 30 min. Lead sorption efficiency increased with increase in pH whereas the opposite trend was observed with iron. The presence of chloride ions greatly reduced the Pb sorption efficiency in the case of Duolite ES 467. Column studies were carried out to recover Pb and Fe individually using Duolite ES 467 resin. The maximum uptake of Pb at pH 2 and 3 was observed to be 11.63 and 33.96 g dm^?3 of resin respectively. Similarly, for Fe at pH 2 and 3 the uptake was observed to be 10.07 and 6.96 g dm^?3 of resin respectively. In the presence of chloride ions, column studies were carried out using Duolite ES 467 for iron and chelating ion‐exchange resin containing hydroxamic acid functional groups for lead sorption. Hydroxamic acid resin's loading capacity remains constant for at least up to 20 cycles. Copyright © 2005 Society of Chemical Industry     

1，3-丙二醇发酵液脱盐用离子交换树脂的筛选

研究了用离子交换树脂处理1,3-丙二醇发酵液,选用6种阳离子交换树脂和3种阴离子交换树脂,以交换容量、电导率和再生时间为指标,考察了树脂的脱盐效果。结果表明：阳离子交换树脂中的D001-cc对1,3-丙二醇发酵液的处理效果最好,150mL树脂的平均交换容量达到240mL,电导率能降到2250gS／cm,再生时间7h;3种阴离子交换树脂中,D301R的去盐效果最好。     

THE INFLUENCE OF CROSSLINKAGE ON THE DISTRIBUTION COEFFICIENTS AND ANION EXCHANGE BEHAVIOUR OF SOME ELEMENTS IN HYDROCHLORIC ACID

Equilibrium distribution coefficients are presented for Cu(II), Zn(II), Cd(II), Fe(III), Ga(III), In(III), Th(IV) and U(VI) on the strongly basic anion exchangers AG1-X2, AG1-X4, AG1-X8, AG1-X10 and AG MP-1 in hydrochloric acid. Coefficients generally increase with increase in crosslinkage, while exchange kinetics show a marked improvement with decrease in crosslinkage. Elution curves for some elements on the lower crosslinked resins AG1-X2 and AG1-X4 and on the macroporous resin AG MP-1 demonstrate the advantages of these resins for some separations.     

Volatile fatty acid adsorption on anion exchange resins: kinetics and selective recovery of acetic acid

ABSTRACT

The removal of volatile fatty acids was examined through adsorption on anion exchange resins in batch systems. During the initial screening step, granular activated carbon and 11 anion exchange resins were tested and the resins Amberlite IRA-67 and Dowex optipore L-493 were chosen for further investigation. The adsorption kinetics and diffusion mechanism and adsorption isotherms of the two resins for VFA were evaluated. Based on the selective adsorption capacity of the resins, a sequential batch process was tested to achieve separation of acetic acid from the VFA mixture and selective recoveries > 85% acetic acid and ~ 75% propionic acid was achieved.