Synthesis of bifunctional ion-exchange resins through the Arbusov reaction: Effect on selectivity and kinetics

Bifunctional ion-exchange resins are synthesized from vinylbenzyl chloride—styrne copolymers. The two types of functional groups are introduced by an Arbusov reaction followed by sulfonation. The effect of ligand ratios, macroporosity, and matrix rigidity on the complexation of Eu (III) from solutions of low pH is quantified. It is found that ion complexation kinetics and selectivity are maximized with resins having both sulfonic and phosphonic acid ligands. Maximum metal ion complexation rates depend on a balance between chemical interactions (i.e., a bifunctional network interacting with a given substrate through an access and a recognition mechanism) and physical parameters (i.e., matrix porosity and rigidity). Structural integrity must be maintained through an appropriate crosslink level in order for the advantage of bifunctionality to be maintained in low-pH solutions. © 1994 John Wiley & Sons, Inc.     

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     

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.     

Bifunctional Phosphinic Acid Resins for the Complexation of Lanthanides and Actinides

Abstract

Phosphinic acid ion exchange/redox resins are synthesized by the reaction between polystyrene beads and phosphorus trichloride followed by base hydrolysis. The reaction requires a temperature of 73°C for full functionalization to occur. The effect of lower functionalization temperatures on resin acid capacity was determined and the concomitant effect on ion exchange investigated. The acid capacity was found to vary from 1.68 mequiv/g to 4.79 mequiv/g in the functionalization temperature range studied (15°C to 73°C). The percent resin sites loaded with zinc ions is independent of the actual capacity. The extracting ability of the phosphinic acid resin for europium, thorium, uranium, americium, and plutontutn was examined as a function of acid concentration from acid nitrate solutions both at varying and constant ionic strength. The phosphinic resins show better extraction for these ions than the sulfonic resins, especially from high acid solution (4M HNO₃) due to the superior coordination ability of the phosphoryl oxygen. They also show a higher selectivity for the ions tested over sodium. For example, under conditions where sulfonic resins absorb 85% of the plutonium in solution, the phosphinic acid resins absorb 99.7%.     

Intraligand cooperation in metal‐ion binding by immobilized ligands: The effect of bifunctionality

Intraligand cooperation between carbonyl and phosphoryl moieties in ion bonding was studied by the synthesis of β‐ketophosphonic acid (βkPh), phosphonoacetic acid (PhAc), and phosphonic acid (Ph) resins. A subsequent reaction gave bifunctional analogues with sulfonic acid as an additional ligand (βkPh_s, PhAc_s, and Ph_s resins). Ionic affinities were quantified with dilute solutions of Cu(II), Cd(II), and Pb(II) in 0.10M HNO₃. The effect of an increased solution ionic strength was studied with a second set of 0.10M HNO₃/0.04M NaNO₃ solutions. The results from the monofunctional resins and nitric acid alone showed that βkPh had the highest metal‐ion affinities, whereas PhAc had affinities similar to those of Ph. Comparing βkPh to Ph led to the conclusion that the carbonyl group was a strong contributor to binding through intraligand cooperation with the phosphoryl group, whereas comparing PhAc to Ph led to the conclusion that the carbonyl group played no role in the ion binding. These opposing conclusions were reconciled as follows: (1) the extent of complexation from the 0.10M HNO₃ solutions increased significantly when the monofunctional resins were sulfonated and (2) a comparison of the results for the monofunctional resins when contacting Cu(II), Cd(II), and Pb(II) in the absence of NaNO₃ with those for the bifunctional resins when contacting those ions in the presence of NaNO₃ showed that the ionic affinities were comparable for Ph and Ph_s, greater for PhAc_s than for PhAc, and comparable for βkPh_s and βkPh. The resins PhAc_s and βkPh displayed comparable ionic affinities that were higher than that of Ph. The results were consistent with the conclusion that, in the monofunctional resin, the affinity of the phosphonoacetate ligand for the metal ions was reduced because of intraligand hydrogen bonding. Intraligand cooperation was, therefore, an important variable in enhancing the metal‐ion affinities, but its effect could be attenuated by intraligand hydrogen bonding. This attenuation could be eliminated by the introduction of a highly hydrophilic group into the matrix. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 463–468, 2004     

Novel Bifunctional Resins in Metal Ion Separations: Ion Exchange/Coordination Resins and Ion Exchange/Precipitation Resins

Abstract

Dual mechanism bifunctional polymers (DMBP's) as metal ion extractants are described within the context of two new examples. The carboxylic acid/pseudocrown resin is a new example of the DMBP class of resins described as ion exchange/ coordination resins. The polyethylene glycol ligand within the resin functions as a coordinating site for metal ions which are brought into the resin via ion exchange with the acid ligand. Initial studies with alkali metal ions are presented. The third general class of DMBP's is also presented. In this case, precipitation is the reaction occurring along with ion exchange thus yielding the ion exchange/precipitation resins. Barium recovery from aqueous solution via barium sulfate precipitation is described.     

Diphonix® Resin: A Review of Its Properties and Applications

Abstract

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.

     

The Synerqistic Solvent Extraction of Manganese by Macrocyclic Crown Ethers in Combination with Didodecylnaphthalene Sulfonic Acid: Effect of Macrocycle Substituents

Abstract

Crown ethers in combination with organophilic cation exchangers synergize the extraction of certain metai ions from aqueous solutions, and their selectivity has been thought largely dependent on the correspondence between the crown other's cavity diameter and the metal ion diameter. This work focuses on two crown ethers, tert. -butylbenzo -15-crown-5 (tBB15C5). and tert, -butylcyclohexano 15-crown-5 (tBC15C5) each of which has a cavity diameter of 1.7 to 2.2 × 10^?10 m. and their extraction of Mn²⁺ (ionic diameter 1.4 to 2.2 × 10^?10 m) from aqueous nitrate solutions. The organophilic cation exchanger used was didodecylnaphthalene sulfonic acid (HDDNS). The data show no observable complexes of the manganese salt of HDDNS     

MECHANISM OF POLYMER-BASED SEPARATIONS. III. METAL ION LOADING CAPACITIES OF REACTIVE POLYMERS WITH SPECIFIC RECOGNITION MECHANISMS

The metal ion selectivity series displayed by a reactive polymer, the phosphinic acid ion exchange/redox resin, was determined from equinormal solutions of 1 milliequivalent metal ion per milliequivalent of polymer ligand sites and compared to results from trace ion solutions. It was found that intervention by the recognition mechanism (i.e., reduction) with Hg(II) and Ag(I) ions from pH 2 aqueous solutions led to high resin loading capacities. Thus, the phosphinic resin/Hg(II) interaction displayed a log D of 3.88, compared to 3.80 from a 10^-4 N solution, indicating that the recognition mechanism obviated any influence of a loading effect. The loading effect was apparent in Fe(III) complexatign wherein a log D of 4.94 was found from a 10^-4 N solution and 0.40 from the equinormal solution. The solution acidity was also an important determinant of selectivity: the series was Fe > Hg > Mn > Ag from 4N HNO₃ and Hg > Ag > Mn > Fe from 0.01N HN0₃. The performance of the phosphinic acid resin was contrasted to that from the non-reactive (i.e., solely ion exchanging) phosphonic acid resin.     

Synthesis and characterization of a bifunctional ion exchange resin with polystyrene-immobilized diphosphonic acid ligands

A new ion exchange resin for the selective complexation of metal ions has been synthesized by functionalizing vinylbenzyl chloride-styrene-divinylbenzene copolymer beads with the sodium salt of tetra(isopropyl) methylene diphosphonate. The effects of bifunctionality, matrix rigidity, degree of functionalization, and macroporosity on final resin properties have been quantified. A sulfonic acid-diphosphonic acid bifunctional resin is highly selective with rapid complexation kinetics. A macroporous polymer matrix crosslinked with 10% divinylbenzene provides optimum results; for example, 99.7% Eu(III) is complexed from a 1M nitric acid solution with a 30-min contact time. The importance of physical crosslinking as well as chemical crosslinking in limiting access of substrates into polymer-supported reagents is discussed. © 1996 John Wiley & Sons, Inc.     

PROTON / NICKEL(II) INTERD1FFUSION COEFFICIENTS ON STRONG ACID RESINS

ABSTRACT

Ion exchange kinetics between proton and nickel(II) ions on sulfonic acid cation resins, with polystyrene-divinylbenzene matrix, type gel and macroporous, in high concentration of the external solution was studied at 298 K using a potentiometric method. The ratio between the amount of ions in the resin and in the solution phase was kept smaller than 0.1. The integral interdiffusion coefficients were determined using the quasi-homogeneous resin phase kinetic models at infinite and finite solution volume. The results were compared and discussed in terms of their range of validity. The influence of the ionic composition of the ion exchanger and matrix nature (gel or macroporous) on the integral interdiffusion coefficients was investigated and discussed. The simpler infinite solution volume kinetic model gives higher values for the integral interdiffusion coefficients than the Paterson's finite solution volume model. The numerical values of the integral interdiffusion coefficients are greater for gel than for macroporous type resin up to     

RADIUM SEPARATION THROUGH COMPLEXATION BY AQUEOUS CROWN ETHERS AND ION EXCHANGE OR SOLVENT EXTRACTION

ABSTRACT

The effect of three water-soluble, unsubstituted crown ethers (15-crown-5 (15C5), 18-crown-6 (18C6) and 21-erown-7 (21C7) on the uptake of Ca, Sr, Ba and Ra cations by a sulfonic acid cation exchange resin, and on the extraction of the same cations by xylene solutions of dinonylnaphthalenesulfonic acid (HDNNS) from aqueous hydrochloric acid solutions has been investigated. The crown ethers enhance the sorption of the larger cations by the ion exchange resin, thereby improving the resin selectivity over calcium, a result of a synergistic interaction between the crown ether and the ionic functional groups of the resin. Similarly, the extraction of the larger alkaline earth cations into. xylene by HDNNS is strongly synergized by the presence of the crown ethers in the aqueous phase. Promising results for intra-Group IIa cation separations have been obtained using each of the three crown ethers as the aqueous ligands and the sulfonic acid cation exchange resin. Even greater separation factors for the radium - calcium couple have been measured with the crown-ethers and HDNNS solutions in the solvent extraction mode. The application of the uptake and extraction results to the development of radium separation schemes it discussed and a possible flowchart for the determination of ²²⁶Ra/²²⁸Ra in natural waters is presented.

     

UPTAKE OF METAL IONS BY A NEW CHELATING ION-EXCHANGE RESIN. PART 4 : KINETICS

Abstract

The rate of uptake of several actinide ions [Am(III), U(VI), Th(IV), Np(IV) and Pu(IV)] and of some transition-metal ions [Co(II), Zn(II), Fe(III) and Cr(III)] at tracer concentration level, from solutions of various compositions, 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. It binds actinide and other ions through the formation of chelate complexes with the phosphoryl groups of the gem-diphosphonic acids. The experiments discussed in this work have allowed us to establish the paramount importance of the presence of the sulfonic groups in obtaining practically useful rates of metal ions uptake. Comparison of the kinetic behavior of Diphonix with that of commercial sulfonic-type resins has shown that Diphonix reacts with the investigated ions as rapidly as do the other resins. Conditions for efficient and rapid stripping of all the investigated cations, including Cr(III), have been found.     

Electrochemical characterization of phosphonic acid cation exchange membrane prepared by plasma-induced graft polymerization

The phosphonic acid cation exchange membrane (CEM) was prepared by plasma-induced grafting of phosphonated glycidyl methacrylate, and its properties were compared with those of sulfonated acid CEM. Although ion exchange capacity and water content of the phosphonic and sulfonic acid CEMs are almost same, the electrical resistance of the phosphonic acid CEM was higher and the transport number was slightly lower compared to the sulfonic acid CEM due to weakly acidic fixed ionic charges. However, those properties of the phosphonic acid CEM were comparable with those of the membranes reported in literature. Current-voltage curves of the membranes showed that the strong fixed charge of sulfonic acid CEM induced more electroconvection of electrolyte near the surface over the limiting current density than phosphonic acid CEM with weaker fixed charge.     

Construction of template polymeric ligand with 8-hydroxy quinoline

8-Hydroxy quinoline was coupled with half diazotized p-pheylene diamine. Complexes of Cu²⁺, Ni²⁺, Zn²⁺, and Co²⁺ were prepared with the resulting dye–ligand. The complexes were then covalently bound into a crosslinked polymer matrix based on styrene–acrylamide copolymer through the ligand moiety. After removal of the metal ions from the polymer matrix, the metal ion absorption capacities of the polymer bound ligands were measured. The procedure could induce some specificities with template effect. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 67:1215–1219, 1998     

SOLVENT IMPREGNATED RESINS CONTAINING DI(2-ETHYL-HEXYL)PHOSPHORIC ACID.II. STUDY OF THE DISTRIBUTION EQUILIBRIA OF Zn(II), Cu(II) AND Cd(II).

ABSTRACT

The extraction of Zn(II), Cu(II) and Cd(II) from nitrate solutions at 0.1 M ionic strength by impregnated resins containing di(2-ethylhexyl)phosphoric acid has been studied at 25 °C.

The distribution coefficient was determined as a function of both pH and extractant concentration in the resin phase. The data were analyzed graphically using the slope analysis method, and numerically using the program LETAGROP-DISTR. The composition of the extracted species in the resin phase has been determined.

Analysis of the results showed that the extraction of these metal ions can be explained assuming the formation of metal complexes in the resin phase with a general composition ML₂(HL) _q where q takes different values depending on the metal. An extraction reaction is proposed and the extraction constants of these species are given.

Finally, a comparison between the extraction of Zn(II), Cu(II) and Cd(II) by di(2-ethylhexyl)phosphoric acid into Amberlite XAD2 and the extraction using organic solvents has been made.     

MECHANISM OF POLYMER-BASED SEPARATIONS. I. COMPARISON OF PHOSPHINIC ACID WITH SULFONIC ACID ION EXCHANGE RESINS

The metal ion complexing ability of the phosphinic acid polymeric extractant has been compared with that for the sulfonic acid ion exchange resin. Based on the performance of the extractants with Fe(III), Hg(II), and Mn(II) under dilute solution/ high acid conditions, both with and without the presence of a large excess of sodium ions, it is concluded that the phosphinic resin operates through an entropy-driven coordination for hard trivalent ions such as Fe(III), an enthalpy -driven coordination for soft ions such as Hg(II) and only ion exchange for hard divalent ions such as Mn(II). The sulfonic resin operates non-selectively through the ion exchange mechanism.     

Synthesis and characterization of chelating resins with amino moieties and application on removal of copper(II) from EDTA complexes

Strong‐field ligands (amino moieties) are introduced into a hydrogel resin to obtain a chelating resin via inversion suspension polymerization. The characteristics of chelating copolymers are measured by using Fourier transform IR spectroscopy (FTIR), elemental analysis (EA), and scanning electron microscopy (SEM). After chelating copolymers adsorb cupric ions, the absorption peak of stretch N? H is shifted to higher frequency because of a coordination reaction from the FTIR spectra. Furthermore, the mechanism of metal complex adsorption on the chelating copolymer is that the strong‐field chelating ligand decomposes the bonding of the metal complexes and recoordinates the cupric ion to a chelating polymer, which is examined via FTIR, SEM with EA, and ionic chromatography analysis. The maximum adsorption capacity of cupric ions is 1.08 mmol/g and the adsorption capacity increases with the increase of the pH of the solution. The stability constant of the Cu chelating copolymer is 10^18.72, and it can have competition adsorption with EDTA in aqueous solution. These amino chelating copolymers can be used not only to recover metal ions but also to move anion pollution in wastewater. It is interesting that parts of the cupric ions adsorbed on the chelating copolymer are reduced into cupreous ions and/or copper atoms after electron spectroscopy for chemical analysis measurement. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 2457–2468, 2005     

N-vinylpyrrolidone/acrylic acid/2-acrylamido-2-methylpropane sulfonic acid based hydrogels: Synthesis,characterization and their application in the removal of heavy metals

In this work, the synthesis of N-vinylpyrrolidone/acrylic acid/2-acrylamido-2-methylpropane sulfonic acid (NVP/AAc/AMPS) based hydrogels by UV-curing technique was studied and their swelling behavior, heavy metal ion recovery capabilities were investigated. The structures of hydrogels were characterized by FT-IR analysis and the results were consistent with the expected structures. Thermal gravimetric analysis of hydrogels showed that the thermal stability of hydrogel decreases slightly with incorporation of AMPS units into the structure. In addition, the morphology of the dry hydrogel sample was examined by SEM. According to swelling experiments, hydrogels with higher AMPS content gave relatively higher swelling ratio compared to neat hydrogel. These hydrogels were used for the separation of Cd(II), Cu(II) and Fe(III) ions from their aqueous solutions. The influence of the uptake conditions such as pH, time and initial feed concentration on the metal ion binding capacity of hydrogel was also tested. The selectivity of the hydrogel towards the different metal ions tested was Cd(II) > Cu(II) > Fe(III). It was observed that the specific interaction between metal ions and ionic co-monomers in the hydrogel affected the metal binding capacity of the hydrogel. The recovery of metal ions was also investigated in acid media.     

Recovery of Zn(II), Mn(II) and Cu(II) in Aqueous Solutions by Foam Fractionation with Sodium Dodecyl Sulphate in Combination with Chelating Agents

Abstract

Adsorptive bubble separation was used to remove polyvalent ion colligends Zn(II), Mn(II) and Cu(II) from aqueous solutions, for which optimum parametrical values that influenced the recovery of these ions were scrutinized. Additionally, the effect of some auxiliary ligands (malic acid, maleic acid, and EDTA) on the recovery was investigated. Sodiumdodecylsulphate (SDS) was used as a collector. The pH was measured as 5.5 and 4.0 for the solutions, which include metal∶SDS and metal∶SDS∶auxiliary ligand, respectively. In the metal : SDS mixtures, SDS has retained metal ions at pH 5.5, which was exactly the value of the membrane filtered water. Therefore, no further pH adjustment was necessary throughout the experiments. The metal ions were determined by inductively coupled plasma optical emission spectroscopy (ICP‐OES). The optimum experimental conditions (run time, SDS concentration, and the concentration of feed solution) on the recovery and enrichment of metal ions were also discussed. The maximum recovery rate was reached within 60 min. The optimum molar ratio between metal and SDS was found to be 1∶5, and it was shown that the recovery of metal ions increased with increasing concentration of SDS. The most suitable initial concentration of metal ions was 2×10^?5 M. The recovery rates for Zn(II), Mn(II) and Cu(II) in the presence of SDS was found to be 90.5, 99.8 and 73.4%, respectively. By adding malic acid, and maleic acid as auxiliary ligands, higher recovery rates were achieved, even in a shorter foaming time. For optimal recovery, the best molar ratio between metal:SDS:auxiliary ligand was 1∶5∶5.