Separation and Recovery of Silver(I) Ions from Base Metal Ions by Melamine‐formaldehyde‐thiourea (MFT) Chelating Resin

Abstract

Melamine‐formaldehyde‐thiourea (MFT) chelating resin were prepared using melamine (2,4,6‐triamino‐1,3,5‐triazine), formaldehyde, and thiourea and this resin has been used for separation and recovery of silver(I) ions from copper(II) and zinc(II) base metals and calcium(II) alkaline‐earth metal in aqueous solution. The MFT chelating resin was characterized by elemental analysis and FT‐IR spectra. The effect of pH, adsorption capacity, and equilibrium time by batch method and adsorption, elution, flow rate, column capacity, and recovery by column method were studied. The maximum uptake values of MFT resin were found as 60.05 mg Ag⁺/g by batch method and 11.08 mg Ag⁺/g, 0.052 mg Zn²⁺/g, 0.083 mg Cu²⁺/g and 0.020 mg Ca²⁺/g by column method. It was seen that MFT resin showed higher uptake behavior for silver(I) ions than base and earth metals due to chelation.     

Combined Ion Exchange—Solvent Extraction (CIESE): A Novel Separation Technique for Inorganic Ions

Abstract

In the present paper a novel separation technique for inorganic ions is described. This has been termed combined ion exchange—solvent extraction (CIESE), because it is assumed that both ion exchange and solvent extraction are operative simultaneously to effect the separations. This concept is illustrated with two examples: the separation of iron(III), Co(II), and Ni(II) on the ion-exchange resins Dowex 50 and Dowex 1 using acetone or tetrahydrofuran—hydrochloric acid mixtures, and the separation of uranium from numerous metal ions on Dowex 50, employing as eluent a medium consisting of tetrahydrofuran—nitric acid. Because this separation principle is superior to methods employing the conventional separation techniques of ion exchange in pure aqueous solutions and of common liquid-liquid extraction, it is expected that it will also find application for the solution of other problems encountered in inorganic analytical chemistry.     

Ion-Exchange and Selectivity Behavior of Thermally Treated and γ-lrradiated Phases of Zirconium(IV) Arsenophosphate Cation Exchanger: Separation of Al(III) from Some Metal Ions and Removal of Cations from Water

Abstract

Ion-exchange and selectivity behavior of zirconium(IV) arsenophosphate (ZAP) has been studied systematically after thermal and irradiation treatments. As a result, an increase in the ion-exchange capacity and a complete reversal in the selectivity sequence for some common metal ions has been observed on heating. The modified phase of ZAP has been utilized successfully for the quantitative separation of aluminum from numerous metal ions and for the removal of cations from water.     

Controlled Formation of Sm(III) Doping Polymer Thin Films Based on a New Macroligand with β-Diketonate

The macroligand of poly(vinyl ketone) has been synthesized. Chelation of polymeric ligands to Sm(III) ions produced metal-centered polymers, which were characterized by ¹H-NMR, FT-IR, UV–Vis, elemental analysis, differential scanning calorimetry, fluorescence spectroscopy and gel permeation chromatography. A poly(vinyl ketone)/Sm(III) thin film was further prepared in situ. This method demonstrates easy processing relative to other methods of obtaining macroligands and Sm(III) complex films. The emission spectrum of the complex film excited by the 325.0 nm He–Cd line was measured at room temperature in the visible region and showed an efficient antenna effect to sensitize the poly(vinyl ketone)–Sm complex. Thus, the material may be used as a material for PLED devices.     

Removal of As(V) and Cr(VI) Ions from Aqueous Solution using a Continuous,Hybrid Field‐Gradient Magnetic Separation Device

Abstract

A continuous flow colloidal affinity magnetic separation device is used for the removal of As(V) and Cr(VI) from aqueous solutions. Langmuir isotherms fit the adsorption behavior of the individual ions on Orica MIEX^® ion exchange particles. In a mixture of equal weight percent As(V) and Cr(VI), the adsorption of As(V) begins only above a critical cut‐off concentration, implying preferential adsorption of the higher valence ion at the available sites. Cr(VI) is removed selectively from the mixture in the continuous flow device, consistent with the presence of a higher concentration of the higher valence ion in the proximity of a charged (anion‐exchange) surface.     

Kinetic and Thermodynamic Separation of Cu(II) and Fe(III) by Liquid-Liquid Extraction with a β-Hydroxy-oxime in Toluene

Abstract

A quantitative study of the thermodynamic and kinetic separation of Cu(II) and Fe(III) by liquid-liquid extraction with toluene solutions of the oxime 2-hydroxy-5-t-octyl (acetophenone oxime) has been conducted. On the basis of the stoichiometry, equilibrium constants, rate laws and rate constants of the extraction reactions of Cu(II) and Fe(III) an equation has been derived which describes how the separation of Cu from Fe varies with the chemical composition of the system, the hydrodynamics of the extracting apparatus and the contact time between the aqueous and the organic phases. Our results show that separations which are not feasible thermodynamically are possible when the contact time between the two phases is kept much shorter than that required to reach equilibrium.     

A Rapid Procedure for the Quantitative Separation of α,ε-Diaminopimelic Acid (DAP)

Abstract

A simple and rapid procedure for the quantitative separation of α,ε-diaminopimelic acid (DAP) from mixture of amino acids, using anion-exchange resin, is presented. The recovery of DAP from the column ranges between 96 and 98%.     

Selective Eu(III) Electro‐Reduction and Subsequent Separation of Eu(II) from Rare Earths(III) via HDEHP Impregnated Resin

Abstract

Eu(III) was selectively reduced to Eu(II) at three‐dimensional glassy carbon cathode in 0.01 mol · dm^?3 hydrochloric acid medium. Eu(III) reduction took place after all the dissolved oxygen was reduced and then proceeded steadily. Separation of Eu(II) from trivalent rare earths (La, Ce, Sm, Gd, Er, Yb) was carried out using a novel impregnated resin based on bis(2‐ethylhexy1)phosphoric acid. Eu(II) showed much lower affinity towards the resin than the trivalent rare earths and broke through the column readily. Eu of purity higher than 99.8% was yielded. The back‐oxidation of Eu(II) was observed during the sorption and Eu(III) was absorbed onto the resin. Adsorbed light and middle rare earths could be stripped from the loaded resin by 3M hydrochloric acid. Stripping of heavy rare earths (Er, Yb) was problematic.     

Reactions of Metal Ion Complexes with Lignin Model Compounds,Part III. Rh(TSPP) Catalyzed Formation of Guaiacol from β-Aryl Ethers in Exceptionally High Yield

Trisodium meso-tetra-4-sulfonatophenylporphinerhodium(III) (Rh(SPP)) was found to be a very effective catalyst for cleaving the β-aryl ether bonds of the lignin model compounds guaiacylglycol β-guaiacyl ether (1) and guaiacylglycerol β-guaiacyl ether (11). In both cases very large amounts of guaiacol (2) were formed regardless of whether the reducing sugar glucose was present or not. With the substituted phenylethane model 1 the other major product was acetovanillone (5); with the substituted phenylpropane model 11 considerable amounts of vanillin (4) were formed. The products obtained with the rhodium catalyst were very different to those formed in the Co(SPP) or anthraquinone (AQ) catalyzed reactions. They were, however, similar to those obtained with Fe(TSPc), although the rhodium catalyst was much more active and formed guaiacol at a much faster rate. In addition to these reactions, the rhodium complex also catalyzes the partial demethylation of the 3, 4-dimethoxyphenyl model compound 10. Mechanisms are proposed for these reactions in which the key steps involve single electron transfer between the catalyst and the substrate.     

Preparation of polyacrylamide–montmorillonite nanocomposite and its application in Cr(III) adsorption

The polyacrylamide–montmorillonite “water in water” (PAM-MMT W/W) emulsion was prepared by dispersion polymerization method in the presence of organo-montmorillonite (OMMT). Based on the analysis of the polymerization process, the structure of material was investigated using thermogravimetry, Fourier transform infrared spectroscopy, X-ray diffractometry, scanning electron microscopy, and transmission electron microscopy experiments. Here, the dispersion was determined to be a blend of PAM W/W emulsion and PAM network interspersed by MMT particles, this unique structure of the material was considered to provide better adsorption ability compared to PAM without MMT. Therefore, a PAM-MMT adsorbent was made from the PAM-MMT W/W emulsion, and its adsorption capacity toward Cr(III), one of the heavy metal pollutants from the tannery waste was investigated. The PAM-MMT nanocomposite was demonstrated to have good Cr(III) removal performance, the maximum adsorption capacity of the nanocomposite was found to be 59.74 mg/g at a pH of 5.5 and temperature of 70°C. Results show that pseudo-second-order kinetic model and Langmuir isotherm were applicable for Cr(III) adsorption.     

A Simple and Highly Selective Biomimetic Oxidation of Alcohols with Hypervalent Iodine(III) Reagent Catalyzed by β-Cyclodextrin in Water

Abstract  

A simple, mild and highly efficient biomimetic oxidation of alcohols to the corresponding aldehydes or ketones with hypervalent iodine(III) reagent catalyzed by β-cyclodextrin was reported. β-cyclodextrin serves as a biological catalyst to enhance the reaction remarkably. The oxidation proceeded in water to afford aldehydes or ketones in excellent yields and high selectivity without remarkable over-oxidation to carboxylic acids. Selective oxidation of primary alcohols in the presence of secondary alcohols was also achieved. A possible mechanism for the oxidation was proposed.     

Effect of Br− on the Adsorption Rate of Palladium(II) Ions onto Condensed-Tannin Gel in Chloride Media

Abstract

In chloride media, chloropalladium(II) species are adsorbed onto tannin gel particles through an inner-sphere redox reaction mechanism containing the intermediate step, formation of a ligand-substituted Pd(II)-tannin complex. In this Pd(II) adsorption process, it was observed that the adsorption rate can be increased by introducing Br^?, a softer ligand than Cl^?, into the aqueous chloride solution. The formation of mixed-ligand palladium(II) complexes accelerates the rate of ligand-substitution reactions with the hydroxyl groups of tannin gel by the trans effect. The adsorption condition can be optimized by controlling the [Br_tot]/[Cl_tot] ratio, in which the predominant Pd(II) species are bromo-chloro palladium(II) complexes, the favorable species for the trans effect.     

Separation of Actinides(III) from Lanthanides(III) in Simulated Nuclear Waste Streams using 6,6′‐Bis‐(5,6‐dipentyl‐[1,2,4]triazin‐3‐yl)‐[2,2′]bipyridinyl (C5‐BTBP) in Cyclohexanone

Abstract

An extraction system comprising 6,6′‐bis‐(5,6‐dipentyl‐[1,2,4]triazin‐3‐yl)‐[2,2′]bipyridinyl (C5‐BTBP) dissolved in cyclohexanone was investigated. The main purpose of this investigation was to extract and separate actinides(III) from lanthanides(III), both of which are present in the waste from the reprocessing of spent nuclear fuel. The system studied showed high distribution ratios for the actinides(III) and a high separation factor between actinides and lanthanides (SF_Am/Eu around 150). The extraction kinetics were fast with equilibrium being reached in 5 minutes. The effects of temperature on the extraction and the stoichiometry of the extracted complex were investigated. The extraction of californium(III) was studied and it was found that the BTBP molecule has a higher affinity for californium than for americium (SF_Cf/Am around 4). This system could be used to separate actinides(III) from lanthanide fission products with high efficiency, if used in conjunction with a pre‐equilibrium step.     

Kinetics and Mechanism of Yb(III) Extraction and Separation from Y(III) with Mixtures of bis(2,4,4‐trimethylpentyl)phosphinic acid and2‐ethylhexyl phosphonic acid mono‐2‐ethylhexyl ester

Abstract

The ytterbium(III) extraction kinetics and mechanism with mixtures of bis(2,4,4‐trimethylpentyl)phosphinic acid (Cyanex272) and 2‐ethylhexyl phosphonic acid mono‐2‐ethylhexyl ester (P507) dissolved in heptane have been investigated by constant interfacial cell with laminar flow. The effects of the stirring rate, temperature, extractant concentration, and pH on the extraction with mixtures of Cyanex272 and P507 have been studied. The results are compared with those of the system with Cyanex272 or P507 alone. It is concluded that the Yb(III) extraction rate is enhanced with mixtures extractant of Cyanex272 and P507 according to their values of the extraction rate constant, which is due to decreasing the activation energy of the mixtures. Atthe same time, the mixtures exhibits no synergistic effects for Y(III), which provides better possibilities for Yb(III) and Y(III) separations at a proper conditions than anyone alone. Moreover, thermodynamic extraction separation Yb(III) and Y(III) by the mixtures has been discussed, which agrees with kinetics results. Extraction rate equations have also been obtained, and through the approximate solutions of the flux equation, diffusion parameters and thickness of the diffusion film have been calculated.     

Effect of Different Synthesis Approaches on Structural and Thermal Properties of Lanthanide(III) Metal–Organic Frameworks Based on the 1H-Pyrazole-3,5-Dicarboxylate Linker

Journal of Inorganic and Organometallic Polymers and Materials - The impact of different synthetic procedures such as: hydrothermal, mechanochemical and precipitation on the structure and thermal...     

Synergistic Solvent Extraction and Separation of Lanthanide(III) Ions with 4‐Benzoyl‐3‐Phenyl‐5‐Isoxazolone and the Quaternary Ammonium Salt

The solvent extraction of the lanthanide(III) ions (without Pm) with a 4‐benzoyl‐3‐phenyl‐5‐isoxazolone(HPBI) alone and in the presence of the quaternary ammonium salt Aliquat 336 in perchlorate form (QClO₄) in C₆H₆ was investigated by the slope analysis method. The composition of the extracted species was determined as Ln(PBI)₃ and Q[Ln(PBI)₄] (Q⁺ is the quaternary ammonium salt cation). The values of the equilibrium constant were calculated. Synergistic effects were found for all lanthanide metals when they were extracted with a binary mixture of HPBI and QClO₄. The influence of the synergistic agent on the extraction process has been discussed. The parameters of the extraction process were determined. The separation factors between adjacent metals were evaluated.     

Ultrasound-Assisted Synthesis of a Novel Nano-Zigzag-Pattern Lead (II) Metal–Organic System: A New Precursor to Produce Nano-Sized PbO

A sonochemical method was used to synthesize a new nano Pb(II) 1D metal–organic zigzag chain [Pb(p-2-einh)NO₂]_n (1) (p-2-einh?=?(1-(pyridin-2-yl)ethylidene)isonicotinohydrazide). The compound was characterized by scanning electron microscopy (SEM), transmission electron microscopy, elemental analysis, IR spectroscopy, thermogravimetric analysis, X-ray powder diffraction, and single-crystal X-ray analysis. The X-ray analysis reveals a 1D zigzag-chain metal–organic polymer structure for 1 that is further extended to a 3D supramolecular structure by—interaction and other labile interactions. A coordination number of six was determined for the Pb(II) ions in PbN₃O₃. Lead oxide nanoparticles were prepared at 180?°C by thermolysis of 1. The average diameter of the nanoparticles was 20 nm. The size and morphology of the PbO samples were observed using SEM, and the structure of the system was optimized by DFT calculations. The calculated structural parameters and FT-IR spectra are consistent with the crystal structure.     

Retention,Thermodynamics and Adsorption Profile of Th(IV) Ions onto 1‐(2‐Pyridylazo)‐2‐Naphthol (PAN) Loaded Polyurethane Foam from Acetate Media and its Separation from Rare Earths

Abstract

The sorption behavior of 2.7×10^?5 M solution of Th(IV) ions on 1‐(2‐pyridylazo)‐2‐naphthol (PAN) loaded polyurethane foam (PUF) has been investigated. The quantitative sorption was occurred from pH 6 to 9 from acetate buffer solutions. The sorption conditions were optimized with respect to pH, shaking time, and weight of sorbent. The sorption data followed the Freundlich, Langmuir, and Dubinin‐Radushkevich (D‐R) isotherms very successfully at low metal ions concentration. The Freundlich isotherm constant (1/n) is estimated to be 0.22±0.01, and reflects the surface heterogeneity of the sorbent. The Langmuir isotherm gives the maximum monolayer coverage is to be 8.61×10^?6 mol g^?1. The sorption free energy of the D‐R isotherm was 17.85±0.33 kJ mol^?1, suggesting chemisorption involving chemical bonding was responsible for the adsorption process. The numerical values of thermodynamic parameters such as enthalpy (ΔH), entropy (ΔS), and Gibbs free energy (ΔG) indicate that sorption is endothermic, entropy driven, and spontaneous in nature. The adsorption free energy (ΔG_ads) and effective free energy (ΔG_eff) are also evaluated and discussed. The effect of different anions on the sorption of Th(IV) ions onto PAN loaded PUF was studied. The possible sorption mechanism on the basis of experimental finding was discussed. A new separation procedure of Th(IV) from synthetic rare earth mixture using batch, column chromatography, and squeezing techniques were reported.     

Separation of Co(II) and Ni(II) from thiocyanate media by hollow fiber supported liquid membrane containing Alamine300 as carrier — investigation on polarity of diluent and membrane stability

The separation of cobalt(II) and nickel(II) ions by HFSLM has been presented. The feed solution is 0.5M thiocyanate containing 300 ppm each of cobalt(II) and nickel(II) ions, whereas extractant is Alamine300 and the stripping solution is ammonia. Cobalt(II) is more preferable with Alamine300 than nickel(II). The effects of pH, Alamine300 concentration and ammonia concentration were investigated. Seven diluents were used: hexane, decanol, chlorobenzene, benzene, dichloromethane, ethylene dichloride and chloroform with different polarity indexes, from 0.1–4.1. Nickel(II) ion which is unpreferable with Alamine300 was used as a tracer to determine the membrane stability. The polarity of the diluents was found to be the main factor influencing the extraction performance and stability of a liquid membrane. The decreasing of polarity of the diluent can prolong the membrane stability, but the percentages of extraction and stripping decreased. The longest lifetime, 200 minutes, was obtained by using hexane as a diluent with the polarity index of 0.1.