Ion Exchange on LIX 65N and Kelex 100 Impregnated Foams

Abstract

The metal capacity vs pH contours and the separation ratios for copper, zinc, and aluminum have been studied for an oxine containing, chelating ion-exchange resin. Metal-metal exchange studies on this resin involving the three metals have demonstrated that this is not a simple substitution process, sorption and desorption of the ions being controlled by solution concentration. The sterically hindered ligand, 8-hydroxyquinaldine, incorporated in a resin, demonstrated much greater selectivity for other metals over aluminum and confirmed published solvent extraction data for this ligand.     

A MECHANISM FOR ENHANCING IONIC ACCESSIBILITY INTO SELECTIVE ION EXCHANGE RESINS

ABSTRACT

A bifunctional monophosphonic/sulfonic acid ion exchange resin with high capacity has been synthesized. Metal ion studies have been carried out with europium, americium, and ferric nitrate in solutions of varying acidity, with and without sodium nitrate added. The bifunctional resin complexes far higher levels of Eu(III) from 0.5 and 1 N nitric acid than the monofunctional phosphonic acid resin. It is postulated that the sulfonic acid ligand provides an access mechanism for the metal ions into the polymer matrix by hydrating the matrix and preventing its collapse in high ionic strength solutions thus allowing for rapid ionic complexation by the selective phosphonic acid ligands. The bifunctional monophosphonic/sulfonic acid resin has both ligands bound to a polystyrene support. It complexes higher levels of metal ions than a comparable resin differing only by having the monophosphonic acid ligand directly bound to the C-C backbone. Results are compared to a diphosphonic / sulfonic acid resin.     

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.     

Co-ordination Polymers of 1,6-bis(8-hydroxyquinolin-5-yl)-2,5-dioxa-3-methyl hexane

Abstract

Co-ordination polymers of novel bis oxine bidentate ligand namely 1,6-bis(8-hydroxyquinolin-5-yl)-2,5-dioxa-3-methyl hexane (BQDMH) have been prepared with different metal ion like Zn⁺², Cu⁺², Ni⁺², Co⁺² and Mn⁺². The novel bis bidentate ligand (BQDMH) is synthesized by condensation of 5-chloromethyl-8-hydroxyquinoline hydrochloride with propylene glycol in presence of base catalyst. All these co-ordination polymers and parent ligand are characterized by elemental analysis, IR spectra and diffuse reflectance spectral studies for their structure determination. The thermal stability and number-average molecular weight ( M _n ) of all these co-ordination polymers have estimated by thermogravimetric analysis and non-aqueous conductometric titration method respectively. Besides this all the co-ordination polymers have also characterized for their magnetic susceptibility and metal to ligand stoichiometry estimation.     

CHELATION PROPERTIES OF POLY(8-HYDROXYQUINOLINE 5,7-DIYLMETHYLENE) TOWARDS SOME TRIVALENT LANTHANIDE METAL IONS

ABSTRACT

The sorption and desorption properties of the chelate-forming phenol-formaldehyde resin, poly(8-hydroxyquinoline 5,7-diylmethylene) towards various trivalent lanthanide ions such as La⁺³, Ce⁺³, Nd⁺³, Sm⁺³, and Gd⁺³ were studied by a static batch equilibration technique as a function of pH and contact time. The resin selectivity and binding capacity towards various lanthanide metal ions are discussed.     

Cation Separations Using A Proton-Ionizable Macrocycle in a Dual Module Hollow Fiber Membrane System

Abstract

Separation of metal cations in aqueous solution using a proton-ionizable macrocycle in a dual module hollow fiber membrane system is described. The advantages of this system, such as easy access to all phases, rapid transport rates, and the potential for continuous operation are maintained with the proton-ionizable macrocycles which allow for proton driven transport. Transport is diffusion limited in the organic phase boundary layer near and on the fibers. Hence, the selectivity of the extraction system is maintained. Selective transport of Ag⁺ over all other cations tested from neutral source phases and of K⁺ over other alkali metal cations from basic source phases using a triazole-18-crown-6 carrier has been demonstrated. Selective K⁺ transport from less basic source phases has been demonstrated using the more acidic thiopyridone-18-crown-6 ligand. However, the large aqueous partition of this ligand makes it difficult to maintain it in the organic phase. Design of the separation systems requires a knowledge of extraction equilibrium constants and partition coefficients. These data have been measured in order to understand these membrane systems.     

Coordination Polymers of 1,9-Bis(8-Hydroxyquinolin-5-yl)-2,5,8-Trioxanonane

ABSTRACT

Coordination polymers of a novel bis(oxine) bidentate ligand, namely 1,9-bis(8-hydroxyquinolin-5-yl)-2,5,8-trioxanonane (BHQTN) (H₂L) have been prepared with the metal ions Zn⁺², Cu⁺², Ni⁺², Co⁺², and Mn⁺². The novel bis(bidentate) ligand BHQTN was synthesized by condensation of 5-chloromethyl-8-hydroxyquinoline hydrochloride with diethylene glycol in the presence of a base catalyst. All of these coordination polymers and the parent ligand were characterized by elemental analyses and IR spectral studies. The diffuse reflectance spectral studies and magnetic susceptibilities of all of the coordination polymers have also been performed. Thermogravimetric parameters such as T_o, T₁₀, T_max., IPDT, and the activation energy of the thermo-degradation process were calculated.     

UPTAKE OF METAL IONS BY A NEW CHELATING ION-EXCHANGE RESIN. PART 2: ACID DEPENDENCIES OF TRANSITION AND POST-TRANSITION METAL IONS*

ABSTRACT

Diphonix^(tm)is a new dual-mechanism polyfunctional resin containing sulfonic and gem-diphosphonic acid groups. In Part 1 of this series the effectiveness of Diphonix in removing actinide ions from very acidic solutions was demonstrated. In this paper we report on the uptake of various transition and post-transition metal ions with Diphonix and two other resins for comparison. The results show that Diphonix has a very high affinity for Fe(III) and Cr(III) in very acidic solutions. From neutral solutions Diphonix exhibits a high selectivity for lead and transition metals over calcium. Conditions for efficient stripping of the investigated ions have been found.     

Ion Exchange Behavior of Selected Elements on Chelex 100 Resin

Abstract

Ion exchange behavior of some selected elements on Chelex 100 ion exchange resin in weakly acidic medium has been investigated. The acidity and the concentration of the supporting electrolyte have considerable influence on the sorption of metal cations by the ion exchanger. Column experiments have revealed that elution of cobalt and zinc in the definite pH range exhibits certain deviation compared to the other examined elements, resulting in doubly peaked elution curve. Apart from the commonly known cation (chelating) exchange function, under appropriate conditions Chelex 100 can also act as an anion exchanger. Ion exchange behavior of mercury in diluted hydrochloric acid medium is an illustration of amphoteric character of this resin. Two regions of pH can be distinguished, which correspond to the specified sorption mechanism of the metal by Chelex 100. In practical aspect, the use of Chelex 100 for the separation of trace amounts of several selected elements is demonstrated.     

CHARACTERISATION OF METALFIX-CHELAMINE AND ITS APPLICATION IN PRECIOUS METAL ADSORPTION

ABSTRACT

The physical and chemical characteristics of the chelating resin Chelamine, which contains a pentamine ligand, are investigated in order to consider its application in the separation of precious metals- Adsorption isotherm experiments for Pt, Pd and Au and kinetic experiments were carried out under batch procedures. The resin presents a high level of adsorption selectivity for Pt(IV), Au(III) and Pd(II) giving a capacity of 2.8 mmol/g, 3.1 mmol/g and 2.0 mmol/g respectively. Acidic solutions, complexing agents, lipophilic anions and ammonia were used for metal elution. NaClO₄ solutions are the most effective eluting agents for Pt(IV) while thiourea is the best stripping agent for both Pd(II) and Au(III). Selective separation of the three metals can be achieved by sequential elution from the resin with NaClO₄ solutions in different HCl concentrations and thiourea 0.5 M.     

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.     

Poly(Ester Amide) with Pendent 8-Quinolinol Moiety as a Novel Oligomeric Ligand

The poly(ester amide) (PEA) was prepared by polycondensation of 1,4-phenylenebisphthalamic acid and the epoxy resin diglycidyl ether of bisphenol-A. The PEA was then treated with 5-chloromethyl-8-quinolinol hydrochloride. The resultant oligomer, designated as PEA-8-quinolinol (PEAQ), was characterized by elemental analysis, IR spectral studies and thermogravimetry. The metal chelates of PEAQ with Cu²⁺, Zn²⁺, Mn²⁺, Ni²⁺, and Co²⁺ metal ions were prepared and characterized by metal:ligand ratio, IR and reflectance studies, magnetic properties, thermogravimetry and microbicidal activity.     

Column Chromatography and Kinetics of Nucleosides and Nucleic Acid Bases on Immobilized Nickel- and Cobalt-CDAE-Sporopollenin

ABSTRACT

Sporopollenin, a natural polymer, has been modified for application as a ligand-exchange material. The ligand-exchange Chromatography with the functionalized Lycopodium clavatum is a useful method for the rapid separation of nucleosides and nucleic acid bases. The synthesis of tris(carboxymethyl) ethylene diamine Lycopodium clavatum has been described. The resin contained functional diaminoethane and carboxyl groups. Nickel(II) and cobalt(II) metal ions can easily be immobilized on this carboxylated-diamino-ethyl (CDAE)-sporopollenin. Physico-chemical and chelating properties of Lycopodium clavatum have been studied extensively. Ligand-exchange chromatography of CDAE-sporopollenin has also been compared to the conventional synthetic chelex-100 resin. The kinetics of cytidine in CDAE-sporopollenin resin has been investigated. The rate measurements have been made by a potentiometric technique. The relative rates at which nucleosides bind to the resin are determined by the actual chemical-exchange reaction between ligands and resin.     

Metal coordination and selectivity with oxine ligands bound to silica polyamine composites

A series of oxine ligands, 5‐X, 8? OH? C₉H₆N (X = H, Cl, SO₃H) have been covalently bound to a silica gel polyamine composite made from a silanized amorphous silica xerogel and poly(allylamine) (BP‐1) by the Mannich reaction. The resulting modified composites WP‐4(X = H), CB‐1(X = Cl), and SB‐1(X = SO₃H) were characterized by elemental analysis, FTIR, and solid state CPMAS‐¹³C‐NMR. Using the analytical data before and after the ligand modification, the ligand loading could be estimated and in combination with metal ion capacities a metal to ligand ratio could be obtained. The composites WP‐4 and CB‐1 both showed ratios of approximately 1 : 1 while the sulfonate modified composite, SB‐1, showed a metal to ligand ratio of 1 : 2. This is tentatively interpreted in terms of a zwitterionic oxine as the dominant species at pH = 2 where the sulfonic acid group is ionized, the quinoline nitrogen is protonated and where two sulfonate groups on adjacent oxines bind a trivalent or divalent ion. All the modified composites show a clear selectivity for trivalent over divalent ions and a good selectivity for gallium over aluminum. The substituent groups on the oxine ligand have only a minor influence on these selectivity trends but SB‐1 shows slightly better capture kinetics. The selectivity for gallium over aluminum is applied to the separation of gallium from aluminum, ferrous, and zinc in an acid ore leach of solid tailings obtained from a zinc mine using WP‐4. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Effect of Ring-Size Variation within Dibenzocrown Ether Resins upon Ion-Pair Sorption of Alkali-Metal Cations from Aqueous and Aqueous Methanol Solutions

Abstract

A batch analysis method has been developed for evaluation of metal salt sorption by crown ether polymers. Selectivity in competitive alkali-metal chloride sorption by a series of formaldehyde condensation polymers of dibenzocrown ethers is influenced by the relationship between the crown ether cavity size and metal ion diameter, as well as the degree of hydration of the metal salt. Effective and selective sorption of KCl from the other alkali-metal chlorides was obtained with a dibenzo-18-crown-6 resin. Excellent sorption selectivity for the monovalent metal chlorides was noted for competitive ion-pair sorption of NaCl, KCl, MgCl₂, and CaCl₂ by this resin. This resin was examined as a stationary phase for selective column separation of KCl from alkali-metal chlorides and of KCl and NaCl from alkali-metal and alkaline-earth chloride mixtures in 80% methanol—20% water.     

Experimental investigation on the enhancement of Mode I fracture toughness of adhesive bonded joints by electrospun nanofibers

ABSTRACT

The use of an electrospun nylon nanofibrous mat at the interface between adjacent plies of a composite laminate is a promising mean to improve the delamination strength, as the nanomat acts a reinforcing web enabling a ply-to-ply bridging. This kind of reinforcement can be potentially used in other applications, such as adhesive bonding, where it may also work as adhesive carrier. The present work is therefore aimed at analysing the potential of an electrospun polymeric nanomat as adhesive carrier and reinforcing web in adhesive bonding. The adhesive is used to pre-impregnate a nylon nanofibrous mat that is then placed at the interface between two metal pieces and cured. The effectiveness of this procedure is evaluated by comparing of the mode-I fracture toughness measured 2024-T3 aluminum alloy DCB (Double Cantilever Beam) specimen bonded using a two-part epoxy resin with and without the nanomat.     

EVALUATION OF A DIETHANOLAMINE CHELATING RESIN USING TWO-PHASE POTENTIOMETRY

ABSTRACT

The synthesis of a polystyrene resin functionalised with diethanolamine is described. Protonation of the resin and complexation of Pb(II), Cd(II), Hg(II), UO₂ ²⁺, Fe(III), Ca(n) and Nd(III) were studied using two-phase potentiometry. From these experiments, apparent formation constants could be calculated and distribution curves obtained. Predictions as to metal ion separations were then possible. Batch experiments with Eu(III) and Pu(IV) were also performed as well as a column experiment for Pb(II) and Ca(II) to test selectivity. The resin shows selectivity towards metal ions that are large and/or have a good affinity for nitrogen donor ligands. Metal ions susceptible to hydrolysis are well complexed by the resin due to its ability to suppress hydrolysis.     

DIPHONIX-CS : A NOVEL COMBINED CESIUM AND STRONTIUM SELECTIVE ION EXCHANGE RESIN*

ABSTRACT

The recently developed Diphonix® resin contains the geminally substituted diphosphonic acid ligand chemically bonded to a styrene-divinylbenzene copolymer. The resin exhibits an extraordinarily strong affinity for actinides, especially in the terra- and hexavalent oxidation states. Therefore the resin has potential for application in TRU removal from nuclear wastes. The Diphonix-CS resin is a Diphonix-type resin that contains also phenolic groups chemically attached to the polymeric matrix. The phenolic groups exhibit high affinity for Cs⁺ ions from highly alkaline media. Thanks to the combined action of the diphosphonic acid and the phenolic groups, the Diphonix-CS resin can simultaneously remove actinide species, Cs and Sr from alkaline media. In this paper the results obtained in the characterization of the new resin are reported, with regard to the uptake equilibrium and kinetics of Cs⁺ and Sr⁺² removal from NaOH solutions and from synthetic alkaline wastes. The chemical and radiolytic stability of the resin has been investigated. The results have indicated that the Diphonix-CS resin is remarkably stable under the experimental conditions of this work (up to 35 days in I to 4 M NaOH, and up to 200 MRad gamma ray absorbed dose). The possibility of stripping the Cs⁺ and Sr⁺² from the resin has been investigated in column experiments by using 1 M HNO₃ as the stripping agent. Some problems encountered in the stripping of Sr⁺² and possible ways to improve the stripping performance are discussed.     

Recovery of Nonferrous Metals from Metal Finishing Industry Wastes

Abstract

Flexible schemes have been devised for recovery of nonferrous metals (copper, chromium, nickel and zinc) from metal finishing industry waste acids and hydroxide sludges. Evaluations conducted with bench scale experimentation established technical feasibility for adaptations of solvent extraction, precipitation and ion exchange separation processes. It was demonstrated with industrial waste samples that by tailoring several separation stages appropriate for specific waste compositions for complex mixtures of widely varying character that efficient separations can be achieved for copper, chromium, nickel or zinc from contaminant metals such as aluminum, chromium or iron.     

ion-Exchange Paper Chromatography of Metal Ions with Mixed Aqueous-Organic Solvents Containing Mineral Acid and a Selective Extractant

Abstract

Mixed solvents containing an organic extractant provide selective separations of metal ions on cation- and anion-exchange papers. The separations of scandium, hafnium plus zirconium, nickel, and thorium from complex mixtures are demonstrated. Various separations in dithizone and dimethyl-sulfoxide media are also reported. Results are often the same as those achieved on columns of resin with the same mobile phase.