Diphonix Resin Research Articles

Novel multifunctional ion exchangers for metal ions removal in the presence of citric acid

The present study deals with the potential application of Purolite S957 and Diphonix Resin® for the removal of rare earth elements from aqueous liquors as a result of the extraction of spent Ni-MH batteries in the presence of citric acid. The effects of the metal ion and the citric acid ratio, pH, ion exchanger dose, contact time, initial concentration and temperature were studied using the batch technique. The Langmuir and Freundlich adsorption isotherm models were used for the description of the adsorption process. The equilibrium adsorption data were fitted using the pseudo first order, pseudo second order, intraparticle diffusion, Boyd, film diffusion and Dumwald-Wagner models. The maximum adsorption capacity q0 obtained from the Langmuir isotherm was found to be 46.63 mg/g for Ni(II) and 60.75 mg/g for La(III) on Purolite S957 as well as 46.55 mg/g for Ni(II) and 60.12 mg/g for La(III) on Diphonix Resin®. The kinetics followed the pseudo second order reaction. Based on the Weber-Morris model the adsorption process proved to proceed in two stages. Based on the Boyd model the rate controlling steps were film and intraparticle diffusions. The adsorption process was spontaneous and endothermic in nature. Reusability of ion exchangers in the desorption studies was also evaluated as a sustainable approach. The physicochemical properties of Purolite S957 and Diphonix Resin® were studied using the ASAP analysis, optical and scanning electron microscopy, potentiometric titration, pHPZC and FT-IR as well as XPS analysis.

Fundamental distribution coefficient data and separations using eichrom extraction chromatographic resins

Distribution coefficient (Kd) data provides the analyst with a powerful set of tools for designing elemental chemical separations. While considerable Kd data exists in the literature for traditional anion and cation exchange resins, a comprehensive Kd study for the majority of the periodic table has not been published to date for several newer Eichrom extraction chromatographic resins. Kd values for the sorption of 41 different of elements on TEVA, TRU, UTEVA, and Diphonix resin were determined in this work. The power of Kd data in designing chemical separations is then demonstrated through development of separation methods for several challenging chemical separations including U/Mo/Te, Zr/Nb/Mo, and Cd isolation. Separation methodologies are finally applied to soil samples, where the ability for each separation to perform under complex matrix conditions is evaluated.

Recovery of metals from waste nickel-metal hydride batteries using multifunctional Diphonix resin

In this study, Diphonix resin containing sulfonic, diphosphonic and carboxylic groups was used to evaluate the adsorption capacity of metal ions contained in the nickel-metal hydride batteries (Ni-MH). This type of ion exchanger can be considered as the multifunctional material having great affinity to many metal ions. Using Diphonix resin adsorption process was carried out for La(III) and Ni(II) ions to characterize kinetic, adsorption and thermodynamic parameters. Preliminary studies of the Nd(III), Ce(III), La(III), Fe(III), Co(II), Ni(II), Cu(II) and Zn(II) metal ions mixture were also performed. The best results of adsorption studies were obtained using 0.2 M HNO3. Diphonix resin exhibits especially good adsorptive properties with respect to rare earth element ions (adsorption efficiency of about 100%) in comparison with the heavy metal ions in the second oxidation state (about 50% or below). The series of affinity of the resin for the studied ions can be presented as follows: La(III) > Fe(III) > Nd(III) > Ce(III) > Cu(II) > Zn(II) > Co(II) > Ni(II). The obtained results confirmed the possibility of further use of the resin for the recovery and separation of rare earth elements from solutions after Ni-MH batteries leaching.

Solvent Extraction of Tungsten(VI) from Moderate Hydrochloric Acid Solutions with LIX 63

The solvent extraction of tungsten(VI) from hydrochloric acid solutions using 5,8-diethyl- 7-hydroxydodecan-6-one oxime (LIX 63) was analyzed in solutions having an initial pH range from 2 to 5, by varying the concentration of metal and extractant. In our experimental range, the cationic exchange reaction as well as the solvation reaction occurred simultaneously. The cation exchange reaction was identified by applying a slope analysis method to the extraction data. The existence of cationic tungsten(VI) species was confirmed by ion exchange experiments with Diphonix resin at pH 3. Further study is needed to identify the nature of this tungsten cationic species. (Received November 23, 2016; Accepted January 10, 2017)

Kinetic modeling analysis for the removal of Cr(III) by Diphonix resin

The sorption of Cr(III) and Cu(II) ions from aqueous solutions with the Diphonix resin in the sodium form have been investigated. Irreversible ion-exchange equilibrium isotherms were obtained for each pair metal/resin and well described by the Langmuir and Langmuir–Freundlich models. The maximum exchange capacities, which are temperature dependent, were estimated to be 2.73 and 3.74meq/gdryresin for Cr(III) at 25 and 50°C, respectively. For Cu(II), those values were 2.45 and 3.17meq/gdryresin. The effects of resin dosage, initial chromium concentration and initial pH on the uptake rate of Cr(III) were studied. The pseudo-second-order rate, pore diffusion and shrinking core models were applied for describing the kinetic data. The shrinking core model, based on non-steady state intraparticle diffusion, enabled a more realistic prediction of the evolution of concentrations of chromium and sodium in solution with time. By fitting the model equations to experimental data, the effective pore diffusivities of Cr(III), Dpef=2.66×10−11m2/s for initial metal concentrations of 250 and 500mg/L and, Dpef=5.31×10−11m2/s for initial concentration of 750mg/L were evaluated.

Evaluación de resinas de intercambio iónico para el control del hierro en soluciones de electro-obtención de cobre

Two commercial resins were evaluated for the extraction of iron from a copper electrowinning solution. Both resins efficiently extract iron. TheMonophosphonic resin has a greater charge capacity than the Diphonix resin and the Diphonix resin shows faster kinetics. Experimental results of the interrupted test and tests with different particle size of resins have demonstrated that extraction kinetics is controlled by diffusion into the particle in both resins. A good agreement with Fick’s model for diffusion inside the particles confirms the proposed mechanism. Finally, temperature favors the process kinetics and its effect on the diffusion coefficient follows Arrhenius law, obtaining a value of 4,89 kcal/mol for theMonophosphonic resin and 4,94 kcal/mol for the Dphonix resin. The aforementioned values are close to typical values for the proposed diffusional control which are 6 to 10 kcal/mol.

Diphonix Resin ® in sorption of heavy metal ions in the presence of the biodegradable complexing agents of a new generation

This paper presents the equilibrium and kinetic studies of Cu(II), Zn(II), Co(II), Pb(II) and Cd(II) complexes with Dissolvine GL-38 (GLDA) and Enviomet™ C140 (EDDS) from aqueous solution by the chelating ion exchanger Diphonix Resin ®. The selected complexing agents Dissolvine GL-38–tetrasodium salt of N,N-bis(carboxylmethyl)- l-glutamic acid and Enviomet™ C140–trisodium salt of ethylenediaminedisuccinic acid belong to the group of a new generation of complexons which easily undergo biodegradation but their complexes are not biodegradable. The effect of pH, phase contact time and concentration has been studied using the batch technique at room temperature. After achieving the best conditions for complexes sorption, isotherms were obtained and fitted to the Langmuir, Freundlich, Temkin and Dubinin–Radushkevich (D–R) models. The kinetic data were fitted using the pseudo-first-order, pseudo-second-order and intraparticle diffusion models. The respective characteristic rate constants were presented. The results showed that the sorption processes of Cu(II), Zn(II), Co(II), Pb(II) and Cd(II) complexes with Dissolvine GL-38 and Enviomet™ C140 on Diphonix Resin ® followed well the pseudo-second-order kinetics.

Evaluation of chelating ion-exchange resins for separating Cr(III) from industrial effluents

In this study two chelating resins containing iminodiacetic acid groups (Amberlite IRC 748 and Diaion CR 11) and a chelating resin based on sulfonic and diphosphonic acid groups (Diphonix) were investigated in order to separate Cr(III) from industrial effluents produced in hard and decorative electroplating. Samples of two industrial plants were characterized during a period of about one year and a half in terms of the metals content (Cr, Cu, Na, Ca, Fe and Ni), Total Suspended Solids (TSS), Total Dissolved Solids (TDS), Chemical Oxygen Demand (COD) and pH. Some of the physical properties of the resins, namely the moisture content, apparent density, intraparticle porosity and the particle size distribution were also evaluated. To quantify the sorption capacity of the resins, batch experiments were performed using synthetic solutions of Cr(III), as well as solutions of Fe in the case of Diphonix. The Langmuir and Langmuir–Freundlich isotherms enabled a good description of the ion-exchange equilibrium data, and the maximum sorption capacity determined for Amberlite and Diaion was 3.6 mequiv./g dry resin. For Diphonix that parameter was 3.4 mequiv./g dry resin. The Diphonix resin exhibits a high selectivity for transition metals (Fe, Ni) over the chromium trivalent. Therefore, it was screened as the most suitable for selectively removing those metal impurities from chromium electroplating effluents. For this resin, the sorption capacity is strongly dependent on the initial pH of the solution. Though, high regeneration efficiencies of Diphonix for stripping Cr(III) were found by using a mixture of NaOH/H 2O 2. The mathematical model tested for describing the dynamics of the process allowed a good fitting to the experimental data and enabled the estimation of effective pore diffusivity of Cr(III). The saturations of Diphonix with industrial effluents demonstrated that the breakthrough capacity of the resin is affected by the presence of other species in solution, such as Fe and Ni. Nevertheless, these effluents may be treated with this resin, being possible to separate Cr(III) from other transition metallic ions in solution.

Determination of Microamounts of Hafnium in Zirconium Using Inductively Coupled Plasma Atomic Emission Spectrometry and Inductively Coupled Plasma Mass Spectrometry during Their Separation by Ion Exchange on Diphonix Chelating Resin

Inductively coupled plasma atomic emission spectrometry (ICP-AES) and inductively coupled plasma mass spectrometry (ICPMS) methods were applied to check the possibility of determination of hafnium in zirconium at a level lower than 100 ppm. A zirconium matrix of hafnium content lower than 10 ppm was obtained using a worked-out separation method exploiting ion exchange on Diphonix resin. Both methods give results in good agreement with each other as well as with those for certified reference material BCR-098 (Zircaloy-4). They were utilized in determination of Hf in the samples collected during separation of microamounts of hafnium from zirconium by the mentioned ion exchange. These results proved the earlier described method of separation on Diphonix resin to be effective even when the initial concentration of hafnium in zirconium decreases from 2.4% to 0.0082%.

New method for removal of spectral interferences for beryllium assay using inductively coupled plasma atomic emission spectrometry

Beryllium (Be) has been used widely in specific areas of nuclear technology. Frequent monitoring of air and possible contaminated surfaces in U.S. Department of Energy (DOE) facilities is required to identify potential health risks and to protect U.S. DOE workers from beryllium-contaminated dust. A new method has been developed to rapidly remove spectral interferences prior to beryllium measurement by inductively coupled plasma atomic emission spectrometry (ICP-AES) that allows lower detection limits. The ion exchange separation removes uranium (U), plutonium (Pu), thorium (Th), niobium (Nb), vanadium (V), molybdenum (Mo), zirconium (Zr), tungsten (W), iron (Fe), chromium (Cr), cerium (Ce), erbium (Er) and titanium (Ti). A stacked column consisting of Diphonix Resin and TEVA Resin reduces the levels of the spectral interferences so that low level Be measurements can be performed accurately. If necessary, an additional anion exchange separation can be used for further removal of interferences, particularly chromium. The method has been tested using spiked filters, spiked wipe samples and certified reference material (CRM) standards with high levels of interferences added. The method provides very efficient removal of spectral interferences with very good accuracy and precision for beryllium on filters or wipes. This new method offers improvements over other separation methods that have been used by removing large amounts of all the significant spectral interferences with greater simplicity and effectiveness. The effective removal of spectral interferences allows lower method detection limits (MDL) using inductively coupled atomic emission spectrometry. A vacuum box system is employed to reduce analytical time and reduce labor costs.

Removal of iron from cobalt sulfate solutions by ion exchange with Diphonix resin and enhancement of iron elution with titanium(III)

Diphonix resin was used to remove ferric iron from a cobalt sulfate solution. In the pH range of 0.5 to 2.5, the solution pH greatly affected the loading of cobalt while the loading behaviour of iron was little changed. Lower pH values and higher resin concentrations led to a higher separation factor between iron and cobalt. Iron was not eluted at all at low acid concentrations while 96% of cobalt was eluted with 30 g/L sulfuric acid. Addition of Ti(III) to the sulfuric acid eluant greatly enhanced the elution of iron even at low acid concentrations. Elution of iron with an eluant containing 4 g/L Ti(III) and 300 g/L sulfuric acid led to complete elution of iron at room temperature. It was found that the enhancement of iron elution with Ti(III) is due to the combined effects of reduction of Fe(III) and competitive adsorption of Ti(III) and Ti(IV) ions.

Radium-228 determination of natural waters via concentration on manganese dioxide and separation using Diphonix ion exchange resin

The objective of this work was to establish a new procedure for 228Ra determination of natural waters via preconcentration of radium on MnO 2 and separation of its daughter, 228Ac, using Diphonix ion exchange resin. Following removal of potential interferences via passage through an initial Diphonix Resin column, the first daughter of 228Ra, 228Ac, is isolated by chromatographic separation via a second Diphonix column. A holding time of >30 h for 228Ac ingrowth in between the two column separations ensures secular equilibrium. Barium-133 is used as a yield tracer. Actinium-228 is eluted from the second Diphonix Resin with 5 ml 1 M 1-Hydroxyethane-1,1-diphosphonic acid (HEDPA) and quantified by addition of scintillation cocktail and LSC counting. Radium (and 133Ba) from the load and rinse solutions from the 2nd Diphonix column may be prepared for alpha spectrometry (for determination of 223Ra, 224Ra, and 226Ra) by BaSO 4 microprecipitation and filtration. Decontamination tests indicate that U, Th, and Ra series nuclides do not interfere with these measurements, although high contents of 90Sr ( 90Y) require additional treatment for accurate measurement of 228Ra. Addition of stable Sr as a “hold back” carrier during the initial MnO 2 preconcentration step was shown to remove most 90Sr interference.

A new method to isolate americium from environmental samples using Diphonix resins

The Aquatic Radioactivity Laboratory of Ciemat has been performing transuranic analyses in different types of matrices such as soils, marine sediments and biota for a good number of years. Analysing americium in large size/volume samples by employing ionic-exchange resins becomes a long and tedious process, usually resulting in low chemical recoveries. A new procedure to isolate americium from environmental samples has been developed by concentrating americium in a Diphonix resin. This resin is then destroyed by calcination at 550°C and further digestion with HNO3 and H2O2 in a microwave oven programmed with increasing pressure stages, reaching 175 psi. Isolation is completed with TRU-Spec and TEVA-Spec columns. Americum is finally quantified by high resolution alpha spectrometry. Analyses carried out with various reference IAEA materials proved that this new method produces higher radiochemical yields, thus allowing treatment of smaller environmental samples.

New fecal method for plutonium and americium

A new fecal analysis method that dissolves plutonium oxide was developedat the Westinghouse Savannah River Site. Diphonix Resin . (Eichrom Technologies),is used to pre-concentrate the actinides from digested fecal samples. A rapidmicrowave digestion technique is used to remove the actinides from the DiphonixResin ., which effectively extracts plutonium and americium from acidic solutionscontaining hydrofluoric acid. After resin digestion, the plutonium and americiumare recovered in a small volume of nitric acid that is loaded onto small extractionchromatography columns, TEVA Resin and TRU Resin (Eichrom Technologies). Themethod enables complete dissolution of plutonium oxide and provides high recoveryof plutonium and americium with good removal of thorium isotopes such as 228Th.

Efficient preconcentration and separation of actinide elements from large soil and sediment samples

Large (approximately 10 g) soil and sediment samples are often required for analysis of low-level man-made actinides for monitoring environmental radioactivity. However, use of large environmental samples often results in significant chemical losses during chemical separations due to matrix interferences. We present a technique based on the ion-exchange resin Diphonix which selectively collects actinides and lanthanides into a common form, which then behaves uniformly and predictably during subsequent separation schemes. Diphonix is attractive for this purpose because it has an extremely high affinity for actinides and a low affinity for most common ions and is resistant to hydrofluoric acid. After being adsorbed onto Diphonix resin in a column mode at a pH approximately 1, actinides are completely eluted with 0.5 M 1-hydroxyethylidene-diphosphonic acid (HEDPA). After destruction of the HEDPA by ozonation or use of Fenton's reagent, Am, Pu, U, and Th are separated from each other and the remaining matrix by use of extraction chromatographic resins. We obtained high and consistent chemical recoveries (mean, 85%), as well as excellent chemical separations, for Am, Pu, U, and Th through the entire procedure for several 10-g soil and sediment samples.

A review of plutonium(IV) selective ligands

This review compares 40 chelating ligands of differing denticity and basicity for the recovery of Pu from process waste streams. These ligands have been shown to form stable Pu(IV) complexes and to be selective for the Pu(IV) ion. Three plutonophiles identified as potentially cost-effective chelators for waste treatment are the siderophore analogue DFO-HOPO, the novel actinide-chelating diphonix resin and the amide substituted N-macrocycle TCM-12aneN 4. Possible means of isolating Pu on related chelating resins are explored.

Diphonix® Resin: A Review of Its Properties and Applications*

The recently developed Diphonix® resin is a new multifunctional chelating ion exchange resin containing geminally substituted diphosphonic acid ligands chemically bonded to a styrene-based polymeric matrix. Diphonix can be regarded as a dual mechanism polymer, with a sulfonic acid cation exchange group allowing for rapid access, mostly non-specific, of ions into the polymeric network, and the diphosphonic acid group responsible for specificity (recognition) for a number of metal cations. The Diphonix resin exhibits an extraordinarily strong affinity for actinides, especially in the tetra- and hexavalent oxidation states. Therefore the resin has potential for applications in TRU and mixed waste treatment and characterization, and in the development of new procedures for rapid actinide preconcentration and separation from environmental samples. Metal uptake studies have been extended to alkaline earth cations, to transition and post-transition metal species, and to metal sorption from neutral or near neutral solutions. Also the kinetic behavior of the resin has been investigated in detail. In view of the above applications the influence of the most commonly occurring matrix constituents (Na, Ca, Al, Fe, hydrofluoric, sulfuric, oxalic and phosphoric acids) on the uptake of actinide ions has been measured. This review paper summarizes the most important results obtained in the studies on the properties of the Diphonix resin and gives an overview of the applications already in existence or under development in the fields of mixed waste treatment, actinide separation procedures, treatment of radwaste from nuclear power and fuel processing plants, and removal of iron from copper electrowinning solutions. *Work performed under the auspices of the Office of Basic Energy Sciences, Divisions of Chemical Sciences and Advanced Energy Projects, U.S. Department of Energy, under contract W-31-109-ENG-38.

UPTAKE OF METAL IONS BY A NEW CHELATING ION EXCHANGE RESIN. PART 9: SILICA GRAFTED DIPHOSPHONIC ACID*

ABSTRACT A new chelating ion exchange resin, Diphonix®, containing geminally substituted diphosphonic acid ligands bonded to a styrene-based polymeric matrix, was recently developed and characterized. To overcome some of the problems associated with the stripping of actinide elements from the resin, a new version of the Diphonix resin has been prepared, where the chelating diphosphonic acid groups are grafted to a silica support. The new material is called Diphosil, for Diphonix on silica. The properties of the new material have been investigated with regard to its equilibrium and kinetic behavior in the uptake of actinide and other ions from acidic solutions. In this work data comparing the Diphonix and Diphosil resins are presented and discussed. The Diphosil resin appears particularly well suited for those cases where the recovery and further processing of the sorbed actinides is not required and the loaded resin can be considered as a solid waste. Because about 90 % of the Diphosil resin weight is sil...

ACIDS. PART 1. P,P"-DI(2-ETHYLHEXYL) METHANEDIPHOSPHONIC ACID

ABSTRACT Two novel extractants, P,P'-di(2-ethylhexyl) methanediphosphonic acid (H2DEH[MDP]) and P.P'-dioctyl methanediphosphonic acid (H2DO[MDP]) have been synthesized at high purity and yield. H2DEH[MDP] was selected for metal extraction studies because of its better physical properties. An investigation of the extraction of alkaline earth cations, Fe(III) and representative tri-, tetra- and hexavalent actinide ions from nitric acid solutions into o-xylene solutions of H2DEH[MDP] at different concentrations was performed. With a few exceptions, the acid dependencies of the extraction of the above metal species strongly resembles those measured in the uptake of the same metals by the chelating ion exchange resin Diphonix®, which contains gem-diphosphonic acid groups chemically attached to a polymeric matrix. H2DEH[MDP] exhibits practically no selectivity among the alkaline earth cations. The almost lack of acid dependency observed with Fe(lll) and tetra- and hexavalent actinides indicates that these ions are chelated by H2DEH[MDP] mostly through the P=0 groups of the extractant. With Fe(lll) and the actinides, variable slopes of the extractant dependencies were measured, their values being strongly dependent on the acidity of the aqueous phase. Typically, the slope of the extractant dependency has a value of about two if the metal is extracted from high acidity solutions. This value becomes progressively lower as the aqueous acidity is reduced, tending to almost zero for acidities around 0.1 M. This phenomenon has been attributed to the formation of metal complexes having different stoichiometrics, ligand protonation and solubility in the aqueous phase. H2DEH[MDP] possesses an extraordinary affinity for actinides and Fe(III). In analogy with the Diphonix resin, this property can be exploited for actinide preconcentration and separation from complex matrices of analytical interest and from mixed waste solutions.

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.