Separation of Metal Ions on Titanium(IV) Tungstate Papers

Abstract

Papers impregnated with titanic tungstate have been used to chromatograph 52 cations in 45 aqueous and mixed solvents. Experimentally, a large number of complex cation separations have been achieved easily and rapidly—Au³⁺, Tl³⁺, Ag⁺, Mo⁶⁺, K⁺, Rb⁺, CS⁺, Ni²⁺, Sb²⁺, Bi³⁺, Be²⁺, and Tl⁺ can be easily separated from numerous metal ions. Several quaternary, ternary, and binary separations have also been achieved, and some important separations are discussed.     

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.     

Synthetic Inorganic Ion-Exchangers. XVI. Thin-Layer Chromatography of Metal Ions on Zirconium Tungstate: Quantitative Separation of Hg(II) from Several Other Metal Ions and from Mixtures

Abstract

Thin-layer chromatography of 23 metal ions in 10 aqueous and mixed solvent systems has been performed on zirconium tungstate ion-exchange material. Several important binary and ternary separations have been achieved. Quantitative separation of Hg(II) from Pb²⁺, Zn²⁺, Cd²⁺, Bi³⁺, Co²⁺, and mixtures has been achieved using 1,4–dioxane as solvent.     

Adsorption of metal cations on wool carbonising waste. Part 1. Adsorption isotherms

The adsorption of various metal ions (Hg²⁺, Ag⁺, Ni²⁺, Cr³⁺, Al³⁺, Zn²⁺ and Pb²⁺) on wool carbonising waste has been investigated to assess its possible use as an adsorbent in water pollution control. Isotherms show that few metal ions (Hg²⁺, Ag⁺ and Ni²⁺) are adsorbed satisfactorily by this material. Moreover, the adsorption capacity of the plant material within the carbonising waste is higher than that of the keratin fraction. Equations fitting the experimental data can be used for the design of processing units.     

Removal of toxic metal ions by using composite cation-exchange material

Polyanilinezirconium(IV) arsenate composite cation exchange material was synthesized under different experimental conditions by the incorporation of polyaniline into the matrices of inorganic precipitate (zirconium(IV)arsenate). The experimental parameters such as concentration, mixing volume ratio, and pH were established for the synthesis of the material. Ion-exchange material that was synthesized at pH 1.0 showed an ion exchange capacity of 1.33 meq g⁻¹ for Na⁺ ions. The composite material exhibits improved ion-exchange capacity along with chemical and thermal stability. The exchanger was characterized based on FTIR, TGA, XRD, and SEM analysis. The X-ray diffraction study shows semi-crystalline nature of the material. The distribution coefficient studies (K_d) of metal ions on the material were performed in diverse solvent systems. Based on K_d values the material was found to be selective for Pb(II) and Hg(II) ions. Some analytically important binary separations of metal ions in synthetic mixtures viz. Ba²⁺-Pb²⁺, Pb²⁺-Ni²⁺, Cd²⁺-Hg²⁺, Ni²⁺-Hg²⁺, Zn²⁺-Pb²⁺, Ca²⁺-Bi³⁺, Al³⁺-Hg²⁺, and Ca²⁺-Pb²⁺ were achieved on the columns of polyanilinezirconium(IV) arsenate cation exchanger. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

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⁺.     

Study of the synthesis of chitosan derivatives containing benzo‐21‐crown‐7 and their adsorption properties for metal ions

Three new chitosan crown ethers, N‐Schiff base‐type chitosan crown ethers (I, III), and N‐secondary amino type chitosan crown ether (II) were prepared. N‐Schiff base‐type chitosan crown ethers (I, III) were synthesized by the reaction of 4′‐formylbenzo‐21‐crown‐7 with chitosan or crosslinked chitosan. N‐Secondary amino type chitosan‐crown ether (II) was prepared through the reaction of N‐Schiff base type chitosan crown ether (I) with sodium brohydride. Their structures were characterized by elemental analysis, infrared spectra analysis, X‐ray diffraction analysis, and solid‐state ¹³C NMR analysis. In the infrared spectra, characteristic peaks of C?N stretch vibration appeared at 1636 cm^?1 for I and 1652 cm^?1 for II; characteristic peaks of N? H stretch vibration appeared at 1570 cm^?1 in II. The X‐ray diffraction analysis showed that the peaks at 2θ = 10° and 28° disappeared in chitosan derivatives I and III, respectively; the peak at 2θ = 10° disappeared and the peak at 2θ = 28° decreased in chitosan‐crown ether II; and the peak at 2θ = 20° decreased in all chitosan derivatives. In the solid‐state ¹³C NMR, characteristic aromatic carbon appeared at 129 ppm in all chitosan derivatives, and the characteristic peaks of carbon in C?N groups appeared at 151 ppm in chitosan crown ethers I and III. The adsorption and selectivity properties of I, II, and III for Pd²⁺, Au³⁺, Pt⁴⁺, Ag⁺, Cu²⁺, and Hg²⁺ were studied. Experimental results showed these adsorbents not only had good adsorption capacities for noble metal ions Pd²⁺, Au³⁺, Pt⁴⁺, and Ag⁺, but also high selectivity for the adsorption of Pd²⁺ with the coexistence of Cu²⁺ and Hg²⁺. Chitosan‐crown ether II only adsorbs Hg²⁺ and does not adsorbs Cu²⁺ in an aqueous system containing Pd²⁺, Cu²⁺, and Hg²⁺. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 1886–1891, 2002     

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     

NEW NITROGEN-CONTAINING MACROCYCLIC LIGANDS COVALENTLY ATTACHED TO SILICA GEL AND THEIR USE IN SEPARATING METAL CATIONS

Several polyaza-crowns and cyclams, each containing an allyl-oxymethyl or other monofunctional group capable of further reaction to attach it to silica gel, have been prepared. As an example of an attachment of a crown to silica gel, allyloxymethyl-substituted diaza-18-crown-6 was reacted with triethoxysilane to form the crown-substituted triethoxysilane This crown-silane material was heated on silica gel to effect a covalent attachment of the crown. The silica gel-bound macrocyclic ligands were found to interact with various metal cations with log K ( H2O) values similar to those of the same cations with unbound macrocycles. A tetraaza-crown bound to silica gel was found to quantitatively remove toxic heavy metal ions, such as Pb²⁺, Hg²⁺ Cd²⁺ Ag⁺and others at the ppb level, from large volumes of aqueous solutions containing those metal ions and much larger amounts of Na⁺Mg²⁺and Ca²⁺ions     

Synthesis and adsorption properties of macroporous cross‐linked polystyrene that contains an immobilizing 2,5‐dimercapto‐1,3,4‐thiodiazole with tetraethylene glycol spacers

A novel chelating resin macroporous cross‐linked polystyrene immobilizing 2,5‐dimercapto‐1,3,4‐thiodiazole via a hydrophilic tetraethylene glycol spacer (PS‐TEG‐BMT) is synthesized and the structure is characterized by means of Fourier transform infrared spectroscopy (FTIR), energy dispersive X‐ray microanalysis (EDX), and elementary analysis. Its adsorption capacity for several metal ions such as Hg²⁺, Ag⁺, Ni²⁺, Pb²⁺, Cd²⁺, Fe³⁺, Bi³⁺, Zn²⁺, and Cu²⁺ are investigated. The initial experimental result shows that this resin has higher adsorption selectivity for Hg²⁺ and Ni²⁺ than for the other metal ions and the introduction of hydrophilic TEG spacer is beneficial to increase adsorption capacities. The result also shows that the Langmuir model is better than the Freundlich model to describe the isothermal process of PS‐TEG‐BME resin for Hg²⁺. Five adsorption‐desorption cycles demonstrate that this resin are suitable for reuse without considerable change in adsorption capacity. POLYM. ENG. SCI., 45:1515–1521, 2005. © 2005 Society of Plastics Engineers     

Modification of poly acrylic acid using calix[4]arene derivative for the adsorption of toxic heavy metals

Poly acrylic acid (PAA) was grafted with p‐t‐butyl calix[4]arene diamine (distal cone) (2) to adsorb toxic heavy metal and alkali metal cations. The grafting method includes the amidation reaction of PAA with calixarene diamine derivative 2 which was carried out in N,N‐dimethylformamide (DMF) and N–methyl‐2‐pyrrolidone (NMP) as solvents. The modified PAAs (PAA‐C1 and PAA‐C2) were characterized by FTIR, ¹H‐NMR, thermal gravimetric analysis (TGA) and differential scanning calorimetry (DSC). PAA‐C1 and PAA‐C2 were used to evaluate the sorption properties of some toxic heavy metal cations (Co²⁺, Cu²⁺, Cd²⁺, Hg²⁺), alkali metal cations (Na⁺, K⁺, Cs⁺), and Ag⁺. Results showed that the modified PAAs were good sorbents for heavy metal and alkali metal cations. The main goal of this project is to design hydrophobically modified PAA that is suitable for ion selective membranes and chemical sensor devices for adsorption of toxic heavy metals. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Synthesis and characterization of new optically active polymers carrying calix[4]arene and amino acid units in the main chain and their binding properties towards toxic heavy metals

BACKGROUND: A series of novel optically active polymers containing upper rim calix[4]arene was prepared from the polycondensation reaction of calix diamine derivative 2 with two optically active diacid chlorides. RESULTS: The optically active compounds were prepared from the reaction of a pyromellitic dianhydride with two chiral amino acids. The optically active polymers were obtained in a yield of 80–86% and had an inherent viscosity of 0.20–0.26 dL g^?1. The polymers were characterized using Fourier transform infrared and ¹H NMR spectroscopy and elemental analysis. Studies of the complexation of the polymers towards some alkali metal and toxic transition metal cations were performed using solid–liquid sorption procedures and comparisons made with the starting monomer. CONCLUSION: It is evident from the complexation studies that the polymers investigated are good polymeric ionophores for alkali metal cations like Na⁺ and K⁺, for Ag⁺ and for toxic heavy metal cations such as Cu²⁺, Co²⁺, Cd²⁺ and Hg²⁺. These polymers are good candidates for use in chiral stationary phases for separation of enantiomers in ionic media, as well for removing metal ions. Copyright © 2009 Society of Chemical Industry     

Physicochemical investigation of radiation‐grafted poly(acrylic acid)‐graft‐poly(tetrafluoroethylene–ethylene) copolymer membranes and their use in metal recovery from aqueous solution

ET‐g‐PAAc membranes were obtained by radiation grafting of acrylic acid onto poly(tetrafluoroethylene–ethylene) copolymer films using a mutual technique. The ion selectivity of the grafted membranes was determined toward K⁺, Ag⁺, Hg²⁺, Co²⁺, and Cu²⁺ in a mixed aqueous solution. The ion‐exchange capacity of the grafted membranes was measured by back titration and atomic absorption spectroscopy. The Hg²⁺ ion content of the membrane was more than that of either the K⁺ or Ag⁺ ions. The presence of metal ions in the membranes was studied by infrared and energy‐dispersive spectroscopy measurements. Scanning electron microscopy of the grafted and metal‐treated grafted membranes showed modification of the morphology of the surface due to the adsorption of K⁺ and Ag⁺ ions. No change was observed for the surface of the membrane that was treated with Hg²⁺ ions. The thermal stability of different membranes was improved more with Ag⁺ and Hg²⁺ ions than with K⁺ ions. It was found that the modified grafted membranes possessed good hydrophilicity, which may make them promising candidates for practical applications, such as for cation‐exchange membranes in the recovery of metals from an aqueous solution. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 2692–2698, 2002     

Regulation of the Peroxidase-Like Activity of nGO,MoS2 and WS2 Nanozymes by Using Metal Cations

Two dimensional nanoparticles (2D-NPs) along with other nanoscale materials have been deemed to be the next generation of artificial enzymes (nanozymes). The low-cost bulk-scale production, ease of storage and modification of such nanomaterials have given nanozymes an advantage over traditional enzymes. Many studies have been aimed at developing methods to increase the performance of these nanozymes, and also identify interfering agents. To investigate the interference of a number of metal cations, we studied the effect of Ti²⁺, Fe²⁺, Ag⁺, Hg²⁺, Co²⁺, Cu²⁺, Ni²⁺, Pb²⁺, Ca²⁺, Zn²⁺ and Mn²⁺ in a nanozyme assays of 2D-NPs using ABTS radical formation. Ti²⁺, Co²⁺, Cu²⁺, Ni²⁺, Ca²⁺, Zn²⁺ and Mn²⁺ ions did not display any notable effect on the peroxidase-like activity of nGO, MoS₂ and WS₂ 2D-NPs. However, Fe²⁺, Ag⁺, Hg²⁺ and Pb²⁺ ions’ effects on the overall ABTS reaction were significant enough to be visualised by partial least square discriminant analysis (PLSDA). We report that, similar to that of many natural enzymes, the nanozyme activity of 2D-NPs is regulated by a number of metal cations allowing their identification and discrimination by using a statistical analysis tool.     

Synthesis and Metal‐ion Binding Properties of New N2S4O2‐ and N2S5O2‐Donor Macrocycles

Abstract

Synthetic procedures for new mixed‐donor macrocycle compounds were reported. The macrocyclic compounds were used in solvent extraction metal picrates such as Ag⁺, Hg²⁺, Cd²⁺, Zn²⁺, Cu²⁺, Ni²⁺, Mn²⁺, Pb²⁺, and Co²⁺. The metal picrate extractions were investigated at 25±0.1°C with the aid of UV‐visible spectrometry. It was found that 6,7,9,10,12,13,23,24‐octahydro‐19H,26Hdibenzo[h,t](1,4,7,13,16,22,10,19) dioxatetrathiadiazasiclotetracosine‐20,27(21H,28H)‐dione showed selectivity towards Ag⁺, Hg²⁺, and Cd²⁺ among the other metals. The extraction constants (Log K_ex) and complex compositions were determined for the Ag⁺ and Hg²⁺ complexes for this compound and 9,10,12,13,23,24,26,27,29,30‐decahydro‐5H,15H‐dibenzo‐[h,w][1,4,7,13,16,19,25‐,10,22] dioxapentathiadiazacycloheptacosine‐6,16(7H,17H)‐dione.     

Synthesis,characterization, and metal ions adsorption properties of chitosan–calixarenes (I)

Calixarene‐modified chitosans (CTS–CA‐I and CTS–CA‐II) were first synthesized by the reaction of chitosan (CTS‐NH₂) with 1,3‐bis‐chloroethoxyethoxy‐2,4‐dihydroxy‐p‐tert‐butylcalix[4]arene (CA‐I) or its benzoyl derivative (CA‐II). Their structures were characterized by infrared and X‐ray diffraction spectroscopy and scanning electron microscopy (SEM). The adsorption of Ni²⁺, Cd²⁺, Cu²⁺, Pd²⁺, Ag⁺, and Hg²⁺ by CTS–CA‐I and CTS–CA‐II was studied and the thermodynamic parameter of two calixarene‐modified chitosans toward Hg²⁺ was deduced. The adsorption properties of CTS–CA‐I and CTS–CA‐II were greatly varied compared with that CTS‐NH₂, especially with the adsorption capacity toward Ag⁺ and Hg²⁺, because of the presence of the calixarene moiety. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 1139–1144, 2003     

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     

Polymer-based fluorescence sensor incorporating triazole moieties for Hg detection via click reaction

The polymer could be obtained by the polymerization of 1,4-dibutoxy-2,5-diethynylbenzene (M-1) with 1,4-diazidobenzene (M-2)via click reaction. The polymer show blue fluorescence. The responsive optical properties of the polymer on various transition metal ions were investigated by fluorescence spectra. Compared with other cations, such as Co²⁺, Ni²⁺, Ag⁺, Cd²⁺, Cu²⁺ and Zn²⁺, Hg²⁺ can exhibit the most pronounced fluorescence response of the polymer Hg²⁺ can exhibit the most pronounced fluorescence response of the polymer due to triazole moiety in the polymer main chain as the metal binding ligand. The results indicate this kind of conjugated polymer with triazole moiety synthesized by click reaction can be used as a selective fluorescence sensor for Hg²⁺ detection.     

Chromogenic sensing of Cu(II) by imino linked thiacalix[4]arene in mixed aqueous environment

Thiacalix[4]arene based imino receptors 4–5 carrying azophenol appendage have been synthesized and studied for their binding abilities towards different metal ions (Li⁺, Na⁺, K⁺, Cd²⁺, Ni²⁺, Cu²⁺, Zn²⁺, Ag⁺, Pb²⁺ and Hg²⁺). Receptor 4 showed selective chromogenic sensing for Cu²⁺ ions in mixed aqueous conditions (THF:H₂O, 9:1 v/v).     

Thiacalixarenes with Sulfur Functionalities at Lower Rim: Heavy Metal Ion Binding in Solution and 2D-Confined Space

Sulfur-containing groups preorganized on macrocyclic scaffolds are well suited for liquid-phase complexation of soft metal ions; however, their binding potential was not extensively studied at the air–water interface, and the effect of thioether topology on metal ion binding mechanisms under various conditions was not considered. Herein, we report the interface receptor characteristics of topologically varied thiacalixarene thioethers (linear bis-(methylthio)ethoxy derivative L², O₂S₂-thiacrown-ether L³, and O₂S₂-bridged thiacalixtube L⁴). The study was conducted in bulk liquid phase and Langmuir monolayers. For all compounds, the highest liquid-phase extraction selectivity was revealed for Ag⁺ and Hg²⁺ ions vs. other soft metal ions. In thioether L² and thiacalixtube L⁴, metal ion binding was evidenced by a blue shift of the band at 303 nm (for Ag⁺ species) and the appearance of ligand-to-metal charge transfer bands at 330–340 nm (for Hg²⁺ species). Theoretical calculations for thioether L² and its Ag and Hg complexes are consistent with experimental data of UV/Vis, nuclear magnetic resonance (NMR) spectroscopy, and single-crystal X-ray diffractometry of Ag–thioether L² complexes and Hg–thiacalixtube L⁴ complex for the case of coordination around the metal center involving two alkyl sulfide groups (Hg²⁺) or sulfur atoms on the lower rim and bridging unit (Ag⁺). In thiacrown L³, Ag and Hg binding by alkyl sulfide groups was suggested from changes in NMR spectra upon the addition of corresponding salts. In spite of the low ability of the thioethers to form stable Langmuir monolayers on deionized water, one might argue that the monolayers significantly expand in the presence of Hg salts in the water subphase. Hg²⁺ ion uptake by the Langmuir–Blodgett (LB) films of ligand L³ was proved by X-ray photoelectron spectroscopy (XPS). Together, these results demonstrate the potential of sulfide groups on the calixarene platform as receptor unit towards Hg²⁺ ions, which could be useful in the development of Hg²⁺-selective water purification systems or thin-film sensor devices.