Comprehensive Equilibrium Analysis of the Complexation of Cu(II) by Tetrathia-14-crown-4 in a Synergistic Extraction System Employing Didodecylnaphthalene Sulfonic Acid

Abstract

Liquid-liquid extraction experiments, UV/vis spectra, and equilibrium modeling by use of the program SXLSQA have been employed to reveal the origin of synergism in the extraction of Cu(II) from sulfuric acid by the tetradentate macrocycle tetrathia-14-crown-4 (TT14C4) combined with the cation exchanger didodecylnaphthalene sulfonic acid (HDDNS) in toluene. The key feature of the system is the 1:1 complexation of Cu(II) by TT14C4. HDDNS functions both as a source of exchangeable protons and as a solvating agent that promotes the formation of small, hydrated aggregates. In the absence of the cation-exchange vehicle provided by HDDNS, the macrocycle does not extract Cu(II) detectably. Combined with HDDNS, however, TT14C4 significantly enhances the extraction of the metal by HDDNS. Comparative UV/vis spectrophotometry indicates the formation of the deep-blue chromophore attributed to the complex ion Cu(TT14C4)²⁺, wherein the planar set of four endo sulfur donor atoms of TT14C4 circumscribes the metal cation. Modeling of the extraction and spectral absorbance data by use of the program SXLSQA supports the conclusion that this 1:1 complex accounts for essentially all of the extracted Cu(II) in excess of that extracted by HDDNS alone. The best model includes HDDNS aggregates incorporating Cu(TT14C4)²⁺ or Cu²⁺ ions. In the analysis, activity effects in both aqueous and organic phases have been taken into account by the Pitzer and Hildebrand-Scott treatments, respectively, with explicit inclusion of the formation of aqueous hydrogen sulfate ion. The model accounts for the effect of variation of the solute components CuSO⁴, H²SO⁴, HDDNS, and TT14C4.     

Rapid Separation of Tl+ and Pb2+ from Various Binary Cation Mixtures Using Dicyclohexano-18-crown-6 Incorporated into Emulsion Membranes

Abstract

Relative transport rates of metal cation nitrates (Na⁺, K⁺, Rb⁺, Cs⁺, Ag⁺, Tl⁺, Ca²⁺, Sr²⁺, Ba²⁺, and Pb²⁺) in a water-toluene-water emulsion membrane system were measured. The toluene component contained the surfactant Span 80 and the crown ether dicyclohexano-18-crown-6. The aqueous receiving phase contained Li₄P2O₇. When each metal cation was individually present in the aqueous source phase, metal extraction was complete within 10 min with the order of extraction being Tl⁺ > Cs⁺ > Ag⁺ > Rb⁺ > K⁺ ≥m Na⁺ and Pb⁺ > Ca²⁺ > Sr²⁺ > Ba²⁺ for uni-and bivalent cations, respectively. Significant extraction was found for all cations except Na⁺, K⁺, and Ba²⁺. Some metal ions were concentrated nearly 10-fold in a 10-min period. Relative transport rates were determined when binary cation mixtures of either Tl⁺ or Pb²⁺ were present at equal concentrations with each of the remaining metal ions in the source phase. Tl⁺, when present with either Na⁺, Cs⁺, or Rb⁺, was selectively extracted from the source phase. Complete and nearly exclusive extraction of Pb²⁺ was observed in the presence of all cations including Tl⁺. The enrichment ratios of Pb²⁺ in the binary mixtures were approximately 10 while those of the second cation were less than 0.5 except for Sr²⁺ which was 0.86. Corresponding separation factors for Pb²⁺ ranged from 1000 to > 6000.     

Equilibrium Analysis of Aggregation Behavior in the Solvent Extraction of Cu(II) from Sulfuric Acid by Didodecylnaphthalene Sulfonic Acid

Abstract

By use of the principles of equilibrium analysis, the liquid-liquid cation exchange of Cu(II) from aqueous sulfuric acid at 25°C by didodecylnaphthalenesulfonic acid (HDDNS) in toluene may be understood in terms of small hydrated aggregated species in the organic phase. Extraction data have been measured as a function of organic-phase HDDNS molarity (1.0 × 10^?4 to 1.0 × 10^?1), aqueous copper(II) sulfate molarity (1.2 × 10^?8 to 1.3 × 10^?2), and aqueous sulfuric acid molarity (0.03 to 6.0). Graphical analysis of linear regions of the data support a model in which organic-phase aggregates of HDDNS function by cation exchange to incorporate Cu(II) ions with no apparent change in aggregation number at low loading. Supporting FTIR spectra and water-content measurements of HDDNS solutions in toluene show that the HDDNS aggregates are highly hydrated. By use of the computer program SXLSQA, a comprehensive equilibrium model was developed with inclusion of activity effects. Aqueous-phase activity coefficients and degree of aqueous bisulfate formation were estimated by use of the Pitzer treatment. Organic-phase nonideality was estimated by the Hildebrand-Scott treatment and was shown to be a negligible effect under the conditions tested. Excluding aqueous sulfuric acid molarities greater than 1, it was possible to model the data to within experimental error by assuming only the equilibrium extraction of Cu²⁺ ion by the aggregate (HDDNS)₄(H₂O)₂₂ and the equilibrium dissociation of (HDDNS)₄(H₂O)₂₂ to the monomer. The dependence of Cu(II) distribution on aqueous sulfuric acid molarity was shown to be quantitatively consistent with a cation-exchange process. In comparison with the graphical approach, the computer analysis allows comprehensive model testing over large, nonlinear data sets and eliminates the need to make limiting assumptions. Overall, the results provide useful insight toward the development of selective synergistic extraction systems in which HDDNS provides a nonselective cation-exchange vehicle in combination with a selective second extractant.     

Highly Efficient Cooperative Membrane Transport of Lead(II) Ions by Aza-18-crown-6 and Palmitic Acid

Abstract

A chloroform membrane system containing a given mixture of aza-18-crown-6 and palmitic acid was applied for the uphill transport of Pb²⁺ ions. In the presence of P₂O₇ ^4? ion as a suitable metal ion acceptor in the receiving phase, the amount of lead ion transported across the liquid membrane after 100 minutes is 89.1 ± 1.3%. The selectivity and efficiency of lead transport from aqueous solutions containing other cations such as Zn²⁺, Cu²⁺, Ni²⁺, Co²⁺, Fe²⁺, Pd²⁺, and Ag⁺ ions were investigated. In the presence of S₂O₃ ^2? ion as a proper masking agent in the source phase, the interfering effects of Cu²⁺ ion were diminished drastically.     

Effect of Macrocycle Type on the Extraction into Toluene of Ag+, Pb2+, and Cd2+ Using a Combination of a Macrocycle and Di(2-ethylhexyl)phosphoric Acid as Extractants

Abstract

The nitrate salts of Ag⁺ and Pb²⁺ are extracted into toluene solutions of one of the following macrocycles: dicyclohexano-18-crown-6 (DC18C6); 1,10-dithia-18-crown-6 (DT18C6); 1,10-diaza-18-crown-6 (2.2); hexathia-18-crown-6 (HT18C6); or cryptand 2.2.1. In addition, the nitrate salt of Cd²⁺ is extracted into toluene solutions of DC18C6 or DT18C6. Ag⁺, Pb²⁺, and Cd²⁺ are also extracted into toluene containing di(2-ethylhexyl)phosphoric acid (HDEHP) and toluene containing a combination of HDEHP and one of the macrocycles. Metal ion extraction is synergistic for the systems containing HDEHP and DC18C6, 2.2, or 2.2.1, but is antagonistic for the systems containing HDEHP and DT18C6 or HT18C6.     

EXTRACTION OP MANGANESE(II) BT MIXTURES OP DIDODECYLNAPHTHALENESOLFONIC ACID AND r-BUTYL- CYCLOHEXANO-15-CROWN-5: SPECTRAL EVIDENCE FOR THE FORMATION OF A MANGANESE(II) - CROWN ETHER COMPLEX

Addition of t-butylcyclohexano-15-crown-5 (tBC-15C5) induces a synergistic effect in the extraction of Mn²⁺ ion with didodecylnaphthalenesulfonic acid (HDDNS). This synergism is the result of the inner-sphere complexation of the crown ether to the manganese(II) ion. The formation of this complex, first suggested by distribution studies, has been confirmed by FTIR experiments. The C-O-C stretching bands for the crown ether ligand shift to lower frequency when Mn²⁺ ion is extracted into a CC14 solution of HDDNS and tBC15C5. A similar C-O-C Btretching band is observed for the crystalline complex [Mn(15C5 ) (Bu₃CS0₃)₂] (where 15C5 = 15-crown-5 and Bu = n-butyl).Formation of analogous complexes is not observed for Fe³⁺, co²⁺,N²⁺,cu²⁺, or zn²⁺ under similar conditions.     

Cu2+ Selective Chromogenic Behavior of Calix[4]arene Derivative

This study involves the copper selective chromogenic response of 5, 11, 17, 23-Tetrakis (N-pyrrolidinomethyl)-25, 26, 27, 28-tetrahydroxycalix[4]arene based mannich base (3). Complexation ability of (3) was explored by examining the effect of a series of various metal ions, such as Li⁺, Na⁺, K⁺, Ag⁺, Ba²⁺, Ca²⁺, Mn²⁺, Mg²⁺, Sr²⁺, Ni²⁺, Cd²⁺, Co²⁺, Cu²⁺, Hg²⁺, Pb²⁺, Zn²⁺, Fe²⁺, Fe³⁺, and Al³⁺, by using UV-visible spectroscopy. Ligand (3) exhibited pronounced selectivity toward Cu²⁺ even in the presence of various co-existing ions. The stoichiometric analysis, i.e., Job's plot revealed that (3) form 1:1 complex with Cu²⁺ ion in DMF-H₂O system. The complexation phenomenon was confirmed by FT-IR spectroscopy that favors the selective nature of (3) with Cu²⁺.     

Evaluation of a (E,E)‐Dioxime Containing Two 15‐Membered Dioxatrithiamacrocycles and its Mononuclear Ni(II) Complex as Ag+ Extractants

Abstract

A macrocyclic vic‐dioxime (1) and its mononuclear Ni(II) complex (2) were studied as extractant. The aqueous solutions of Ag⁺, Mn²⁺, Pb²⁺, Ni²⁺, Cu²⁺, Cd²⁺, and Zn²⁺ picrates were used for extraction experiments. The solutions of the ligands in two different organic solvents were used as organic phases. The metal picrate extractions were carried out at 25±0.1°C by using UV‐visible spectrometry. The most effective transport was observed for Ag⁺ picrate among the tested metal picrates. The effect of pH on the extraction of Ag⁺ picrate was evaluated with the ligands. The ratio of extracted Ag‐complex to chloroform phase was 2:1 (L:M) for (2). In other cases the ratios were 1:1 for both (1) and (2). Molar ratio method was also used to demonstrate the composition. The values of the extraction constants (log K_ex) were determined for the extracted Ag‐complexes.     

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     

Catalytic Ozonation of Citric Acid by Metallic Ions in Aqueous Solution

Ozonation of citric acid in water catalyzed by different ions from the first row of transition metals (Mn²⁺, Co²⁺, Ti⁴⁺, Fe²⁺, Cu²⁺, Ni²⁺ and Zn²⁺) was investigated at room temperature. The results showed that at pH=2, where the decomposition of citric acid is negligible by only ozone, the following order of efficiency of metallic ions for the decomposition of citric acid by ozone, and also for the TOC removal, was obtained: Mn²⁺ > Co²⁺ > Ti⁴⁺ > Fe²⁺. Cu²⁺, Ni²⁺ and Zn²⁺ showed negligible efficiency under the same experimental conditions. At pH=5.5, Mn²⁺ and Co²⁺ showed slightly higher efficiency than at pH=2 while Ti⁴⁺ and Fe²⁺ showed insignificant effect at this pH value. On the other hand, at pH=7 the investigated catalysts showed no obvious catalytic efficiency for the decomposition of citric acid by ozone.     

Complexation studies of some newly synthesized precursors for substituted dibenzo and dibenzodiaza crown ethers

This study represents the synthesis of dibenzo and dibenzodiaza crown ether precursors with various functional groups in good yield by employing four different methods using polar protic and aprotic solvents with high boiling points. Also the complexation abilities of all synthesized ligands with Cu²⁺, Zn²⁺, and Ag⁺ were studied by conductometry; thus the conductometric behavior of Cu(NO₃)₂, ZnCI₂, and AgNO₃ in 80% dioxane–water mixture was investigated in the presence of these ligands. The order of formation constant for complexes of the ligands with Cu²⁺, Zn²⁺, and Ag⁺ ions was found to be: Cu²⁺ > Zn²⁺ > Ag⁺ for the ligands of VI , VII , XI , and XII ; Cu²⁺ > Ag⁺ > Zn²⁺ for the ligands of III and VIII ; and Zn²⁺ > Cu²⁺ > Ag⁺ for the ligands of I , II , IV , V , IX , and X . © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 2497–2501, 2004     

Effect of metallic ions in photo-induced graft copolymerization onto cellulose

In photo-induced graft copolymerization of methyl methacrylate onto cellulose, the effect of metallic ions as sensitizer was investigated. Some metallic ions were effective in their adsorbed states and accelerated the formation of grafts in the order Fe²⁺ > Ag⁺ > Fe³⁺. However, Cu²⁺ acted negatively, and little effect was observed for Co²⁺, Ni²⁺, Mn²⁺, Zn²⁺, and Cr³⁺. In the systems in which aqueous metallic salt solutions were added, the formation of grafts was generally depressed, but Fe³⁺ was an exception. The effect of metallic ions on the scission reaction of cellulose main chains did not necessarily agree with the effect on the formation of grafts. This is attributed to the varied interaction between cellulose and the different active species produced by irradiation, depending on the type of metallic ions used.     

Highly Efficient and Selective Transport of Cu(II) with a Cooperative Carrier Composed of Tetraaza-14-Crown-4 and Oleic Acid through a Bulk Liquid Membrane

Tetraaza-14-crown-4 and oleic acid was successfully applied for transport of Cu(II) in chloroform bulk liquid membrane. The uphill moving of Cu(II) during the liquid membrane transport process has occurred. The main effective variable such as the type of the metal ion acceptor in the receiving phase and its concentration, tetraaza-14-crown-4 and oleic acid concentration in the organic phase on the efficiency of the ion-transport system were examined. By using L-cysteine as a metal ion acceptor in the receiving phase, the maximum amount of copper (II) transported across the liquid membrane was achieved to 96 ± 1.5% after 140 minutes. The selectivity of copper ion transport from the aqueous solutions containing Pb²⁺, Tl⁺, Ag⁺, Co²⁺, Ni²⁺, Mg²⁺, Zn²⁺, Hg²⁺, Cd²⁺ and Ca²⁺ ions were investigated. In the presence of CH₃COONH₄ and Na₄P₂O₇ as suitable masking agents in the source phase, the interfering effects of Pb⁺² and Cd²⁺ were diminished drastically.     

Preparation and adsorption selectivity for Hg(II) and Ag(I) of chelating resin immobilizing benzothiazolyl group on crosslinked polystyrene via hydrophilic sulfur‐containing PEG spacer

A new chelating resin incorporating 2‐mercaptobenzothiazole (MBZ) into macroporous chloromethylated polystyrene via hydrophilic spacer of polyethylene glycol containing sulfur was synthesized. The resin was characterized by elementary analysis and infrared spectra. The adsorption capacity of the resin for Ag⁺, Hg²⁺, Cu²⁺, Zn²⁺, and Pb²⁺ as a function of pH was determined. The effects of interference ions, such as Na⁺, Mg²⁺, Ca²⁺, Ba²⁺, Cu²⁺, Zn²⁺, and Pb²⁺, on percent recovery were also investigated. The results showed that the resin could effectively remove Hg²⁺ and Ag⁺ from solutions containing a large excess of Na⁺, Mg²⁺, Ca²⁺, Ba²⁺, Cu²⁺, Zn²⁺, and Pb²⁺. In column operation, it was observed that Hg²⁺ and Ag⁺ in trace quantities were effectively removed from binary metal ions. The percent recovery of the resin for Hg²⁺ and Ag⁺ was >98.6% and >97.5%, respectively. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 5034–5038, 2006     

Extraction of Alkali Metal Cations by Lipophilic Dibenzo-14-crown-4-carboxylic Acids

Abstract

The extraction of alkali metal cations by the lipophilic crown ether, bis-t-octylbenzo-14-crown-4 (BOB14C4), three derivatives of BOB14C4 having pendant carboxylic acid sidearms, and a lipophilic carboxylic acid, 2-methyl-2-heptylnonanoic acid (HMHN) was studied by two-phase potentiometric titration and ion-chromatography. The lipophilic, ionizable crown ethers, BOB14C4-acetic acid (BOB14C4AA), BOB14C4-propanoic acid (BOB14C4PA), and BOB14C4-oxyacetic acid (BOB14C4OAA) extract cations efficiently from aqueous mixed alkali metal chloride solutions into 1-octanol by an ion-exchange mechanism in the range p[H] > 7, as does HMHN. The mode of attachment of the ionizable sidearm, via an ether linkage (BOB14C4OAA) versus a carbon linkage (BOB14C4AA and BOB14C4PA), has a significant effect on the cation selectivity and extraction efficiency of these extractants. BOB14C4 exhibits no p[H] dependent extraction behavior and has no significant effect on the extraction of alkali metal cations by HMHN in a mixture of these two compounds. Although BOB14C4AA and BOB14C4PA extract cations at lower p[H] than HMHN, all three compounds exhibit similar selectivity for Li⁺ over Na⁺, K⁺, Rb⁺ and Cs⁺. A significant reversal in selectivity is observed with BOB14C4OAA, which extracts Na⁺ and K⁺ selectively over Li⁺, Rb⁺, and Cs⁺ and at significanty lower p[H] than BOB14C4AA, BOB14C4PA, or HMHN. The unique behavior of BOB14C4OAA may be attributed to the presence of the ether linkage between the crown ether and the pendant carboxylic acid.     

Macrocycle-Mediated Transport in a Bulk 1.5 M HNO3-CHCI3-0.01 M HNO3 Membrane System of Pd2+ and Mn+ from Pd2+Mn+ Mixtures

Abstract

Pd²⁺ has been transported using sulfur substituted macrocycles as carriers and several Mⁿ⁺ (Mⁿ⁺ = Lⁱ⁺, Na⁺, K⁺, Rb⁺, Cs⁺, Mg²⁺, Ca²⁺, Sr²⁺, Ba²⁺, Ag⁺, TL⁺, Cd²⁺, and Pb²⁺) have been transported using 18-crown-6 (18C6) and sulfur substituted macrocycles as carriers in a 1.5M HN0₃/CHCL₃3/0.01M HNO₃ bulk liquid membrane system. Competitive Pd²⁺-Mⁿ⁺ transport studies have also been carried out for the same systems. The cyclic polyether 18C6 transports Mⁿ⁺ selectively over Pd²⁺ for all Mⁿ⁺ except Li⁺, Mg²⁺, and Cd²⁺. In the cases of these three cations, no transport was found for either Pd²⁺ or Mⁿ⁺. Generally, the sulfur substituted macrocycles transport Pd²⁺ selectively over Mⁿ⁺.     

Chromatographic Separations of Metal Ions on Zirconium Tungstoarsenate Impregnated Ion-Exchange Papers

Abstract

A new heteropolyacid salt ion-exchanger, zirconium tungstoarsenate, has been used for preparing impregnated ion-exchange papers. Twenty-nine metal ions have been chromatographed and R_F values determined in seven different mixed solvent systems containing 1-propanol and HNO³ or HCl. On the basis of the difference in selectivities for different metal ions on impregnated papers, a large number of binary and ternary separations has been obtained. Some of the important separations achieved are Ag⁺–Tl⁺, Ag⁺–Pt(IV), Zn²⁺–Hg²⁺, Sb³⁺–Bi³⁺, Zn²⁺–UO₂ ²⁺, Fe²⁺–Fe³⁺, Sb³⁺–Bi³⁺–Hg²⁺, Ag⁺–Ba²⁺–UO₂ ²⁺, and Ag⁺–Zn²⁺–Cu²⁺–Sn²⁺. The results are compared with those obtained on plain papers.     

ION-EXCHANGE EQUILIBRIUM OF THE Cu2+/H+, Zn2+/H+ AND Pb2+/H+ IONS ON HYDRATED FERRIC OXIDE

ABSTRACT

The ion exchange of trace amounts of Cu²⁺, Zn²⁺ and Pb²⁺ with the hydrogen-form of hydrated ferric oxide as a function of nitric acid concentration has been studied at 25, 30,35 and 60^°C. Ion exchange of these cations increases with increasing temperature in the investigated temperature range. From these results, equilibrium constants for the Cu²⁺/H⁺, Zn²⁺/H⁺ and Pb²⁺/H⁺ ion exchange on hydrated ferric oxide and thermodynamic quantities for these reactions were calculated, and some predictions made for the exchange process taking place in this material. The selectivity series is Zn²⁺ > Cu²⁺ > Pb²⁺.     

Studies on selective adsorption resins. XXI. Preparation and properties of macroreticular chelating ion exchange resins containing phosphoric acid groups

Macroreticular cation exchange resins containing phosphoric acid groups (RGP) were prepared by the reaction of glycidyl methacrylate–divinylbenzene copolymer [or poly(glycidyl methacrylate)]beads (RG) with phosphoric acid or phosphorous oxychloride, and the adsorption behavior of metal ions on the RGP was investigated. The phosphorylation of the polymer beads could be effectively carried out by treatment of the polymer beads with 85% phosphoric acid at 80°C for 3 h. The RGP obtained from glycidyl methacrylate–divinylbenzene (2 mol %) copolymer beads showed high cation exchange capacity, salt splitting capacity, and adsorption capacity for Cu²⁺, Zn²⁺, Cd²⁺, Ca²⁺, and Ag⁺. On the other hand, the RGP obtained from poly(glycidyl methacrylate)beads had high adsorption capacity for Al³⁺, Fe³⁺, and UO₂²⁺. The RGP prepared by treating the RG with phosphoric acid had a higher selective adsorption for Li⁺ than for Na⁺.     

Adsorption properties of novel chelating resins containing 2‐amino‐5‐methylthio‐1,3,4‐thiadizole and hydrophilic spacer arms for Hg2+ and Ag+

The adsorption properties, including the adsorption kinetics, adsorption isotherms, and adsorption selectivity, of newly formed chelating resins that contained a heterocyclic functional group and a hydrophilic spacer arm of poly(ethylene glycol) [polystyrene–diethylene glycol–2‐amino‐5‐methylthio‐1,3,4‐thiadizole (PS–DEG–AMTZ) and polystyrene–triethylene glycol–2‐amino‐5‐methylthio‐1,3,4‐thiadizole (PS–TEG–AMTZ)] were studied in detail. The results show that the adsorption kinetics of PS–DEG–AMTZ and PS–TEG–AMTZ for Hg²⁺ and Ag⁺ could be described by a pseudo‐second‐order rate equation. The introduction of a spacer arm between the polymeric matrix and functional group was beneficial for increasing the adsorption rates. The apparent activation energies of the resins for Hg²⁺ and Ag⁺ were within 20.89–32.32 kJ/mol. The Langmuir model could describe the isothermal process of Hg²⁺ and Ag⁺. The competitive adsorption of the resins for Hg²⁺ and Ag⁺ in binary mixture systems was also investigated. The results show that Hg²⁺ and Ag⁺ were adsorbed before the other metal ions, such as Cu²⁺, Zn²⁺, Fe³⁺, Cd²⁺, and Pb²⁺, under competitive conditions. Five adsorption–desorption cycles were conducted for the reuse of the resins. The results indicate that these two resins were suitable for reuse without considerable changes in the adsorption capacity. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010