Evaluation of heavy metal kinetics through pyridine based Th(IV) phosphate composite cation exchanger using particle diffusion controlled ion exchange phenomenon

In this study, the ion exchange kinetics of selected heavy metals such as Cd, Cu, Pb and Zn through the pyridine based thorium(IV) phosphate composite cation exchange material was studied. The ion exchange kinetics over this composite cation exchanger followed the particle diffusion controlled ion exchange phenomenon. Kinetics parameters also revealed that the mechanism of ion exchange for heavy toxic metal ion is feasible to explore the wastewater treatment.     

Synthesis, Characterization and Crystal Structure of a Novel One-Dimensional Supramolecular Dimethyltin (IV) Compound

A novel one-dimensional (1D) supramolecular dimethyltin compound of (Me₂SnO)₂(Me₂SnOCH₃)(O₂CCH₂SC₄H₃N₂-2,6)[Me₂Sn(O₂CCH₂SC₄H₃N₂-2,6)₂]·CH₃OH was prepared by the reaction of (CH₃)₂SnCl₂ with (2-pyrimidylthio)acetic acid with CH₃ONa as a base. The title compound contained four different tin atom environments. Among them, Sn(1) and Sn(2) were both five-coordinate with distorted trigonal bipyramidal geometries, Sn(3) was six-coordinate with a distorted octahedral geometry and Sn(4) was seven-coordinate with pentagonal bipyramidal geometry. Meanwhile, the compound was stabilized in a 1D infinite chain by intermolecular Sn–O bonds. An erratum to this article can be found at     

Synergistic Enhancement and Separation of Zirconium(IV) and Hafnium(IV) with 3-Phenyl-4-Benzoyl-5-Isoxazolone in the Presence of Crown Ethers

Abstract

3-Phenyl-4-benzoyl-5-isoxazolone (HPBI) was synthesized and examined with regard to the synergistic solvent extraction behavior of zirconium(IV) and hafnium(IV) in the presence of various crown ethers (CEs), namely, 18-crown-6 (18C6), dicylohexano-18-crown-6 (DC18C6) and benzo-15-crown-5 (B15C5) from hydrochloric acid solutions. The results demonstrated that zirconium(IV) and hafnium(IV) were synergistically extracted into chloroform with mixtures of HPBI and CEs as ZrO(PBI)₂ · CE and HfO(PBI)₂ · CE, respectively. The complexation strength follows the order DC18C6 >18C6 > B15C5. The addition of CEs not only enhances the extraction efficiency of zirconium(IV) and hafnium(IV) but also significantly, especially in the presence of B15C5, improves the selectivity (Zr/Hf = 4.73) between these metal ions as compared to HPBI alone (Zr/Hf = 2.09). On the other hand, selectivity has been moderately decreased by the addition of 18C6 or DC18C6 to the metal-chelate system.     

Synthesis, ion exchange properties and applications of tin(IV) antimonoarsenate

Crystalline (c-SnSbAs) and amorphous (a-SnSbAs) samples of tin(IV) antimonoarsenate were prepared at different pH values from 0 to 5. Crystalline and amorphous samples, prepared at pH 1 having ion exchange capacities of 1.00 meq/g and 0.90 meq/g respectively, were selected for further studies. The materials show high thermal and chemical stability. Distribution coefficients (K_d values) for 22 metal ions have been determined in demineralised water. Structural studies based on IR, XRD, TGA, DTA are discussed. Some quantitative binary separations such as Mg²⁺–Mn²⁺, Cd²⁺–Mn²⁺, Ba²⁺–Mn²⁺ and Ni²⁺–Cu²⁺ were achieved on a-SnSbAs and ion selective electrodes prepared from c-SnSbAs are reported.     

From non-porous crystalline to amorphous microporous metal(IV) bisphosphonates

Porous layered hybrid materials have been prepared by the reaction of organo-bisphosphonate ligands, 4-(4′-phosphonophenoxy)phenylphosphonic, 4,4′-biphenylenbisphosphonic and phenylphosphonic acids, with metal(IV) cations (Zr and Sn). Crystalline Zr(IV) and Sn(IV) layered bisphosphonates were also prepared, which were non-porous. The amorphous M(IV) bisphosphonates showed variable compositions and textural properties ranging from mainly mesoporous to highly microporous solids with BET surface areas varying from 300 to 480 m² g⁻¹, micropore volumes ranging 0.10–0.20 cm³/g, and narrow porous size distributions for some materials. N₂ isotherms suggest that Sn(IV) derivatives show a comparatively higher micropore contribution than the Zr(IV) analogous at least for the ether-bisphosphonate hybrids. Sn(IV) bisphosphonates exhibit high microporosities without the need of using harmful DMSO as solvent. If ether-bisphosphonic acid is partially replaced by less expensive phenylphosphonic ligand, porous products are also obtained. ³¹P and ¹⁷F MAS NMR and XPS data revealed the presence of hydrogen-phosphonate groups and small (F⁻, Cl⁻ and OH⁻) anions, which act as spacer ligands within the inorganic layers, in these hybrid materials. The complexity of the inorganic layers is higher for the Sn(IV) bisphosphonates likely due to the larger amount of small bridging anions including fluorides. It is suggested that the presence of these small inorganic ligands may be a key factor influencing both, the interaction of the inorganic layer with the bisphosphonate groups, which bridge the inorganic layers, and the generation of internal voids within a given inorganic layer. Preliminary studies of gases adsorption (H₂ and NO) have been carried out for selected Sn(IV) bisphosphonates. The H₂ adsorption capacity at 77 K and 1 bar was low, 0.26 wt%, but the NO adsorption capacity at 1 bar and 298 K was relatively high, 4.2 wt%. Moreover, the hysteresis in the NO isotherms is indicative of partial strong irreversible adsorption of NO.     

Note: Zr(IV)-Immobilized Resin Prepared by Surface Template Polymerization for Fluoride Ion Removal

Abstract

A novel adsorbent Zr(IV)-immobilized resin was prepared to remove fluoride ions from tap water and industrial wastewater. In order to enhance both the kinetics and efficiency, large pathways were formed in the resin for fluoride ion adsorption and the Zr(IV)-phosphate complexes were immobilized on the polymer surface by surface-template polymerization. The Zr(IV)-immobilized resin had a fluoride adsorption capacity of 0.30 mmol/g. The morphology of the Zr(IV)-immobilized resin was evaluated by measuring the specific surface area, pore volume, and pore size distribution. The resin possessed large amounts of large macropores with diameters around 300 nm. The molecular structure at the fluoride adsorption sites was investigated by measuring the amounts of phosphorus, zirconium, and fluoride ion in the resin, and developing a model complex using computational chemistry. On the polymer surface, a fluoride ion/Zr(IV)/dioleyl phosphoric acid complex with an ideal F:Zr:P mole ratio of 3:1:3 could be formed.     

Poly(aspartic acid) Biohydrogel as the Base of a New Hybrid Conducting Material

In the present study, a composite made of conducting polymer, poly(3,4-ethylenedioxythiophene) (PEDOT), and a biodegradable hydrogel of poly(aspartic acid) (PASP) were electrochemically interpenetrated with poly(hydroxymethyl-3,4-ethylenedioxythiophene) (PHMeDOT) to prepare a new interpenetrated polymer network (IPN). Different cross-linker and PEDOT MPs contents, as well as different electropolymerization times, were studied to optimize the structural and electrochemical properties. The properties of the new material, being electrically conductive, biocompatible, bioactive, and biodegradable, make it suitable for possible uses in biomedical applications.     

Separation of rhodium(III) and iridium(IV) chlorido complexes using polymer microspheres functionalized with quaternary diammonium groups

Merrifield resin functionalized with different quaternary diammonium groups derived from ethylenediamine (EDA), tetramethylenediamine (TMDA), hexamethylenediamine (HMDA), 1,8-diaminooctane (OMDA), 1,10-diaminodecane (DMDA) and 1,12-diaminododecane (DDMDA) were investigated for the separation of [RhCl₅(H₂O)]^2? and [IrCl₆]^2?. Selective loading of [IrCl₆]^2? in 6 M HCl medium onto the column was achieved in the presence of [RhCl₅(H₂O)]^2? by the synthesized sorbents. The iridium loading capacities were 3.80, 6.49, 13.07, 19.29, 27.09 and 4.36 mg/g for EDA, TMDA, HMDA, OMDA, DMDA and DDMDA-functionalized microspheres, respectively. The materials showed great potential for application in separating rhodium and iridium from aqueous HCl solutions.     

Solvent Extraction Investigations on Pu(IV) and Th(IV) Complexes with Hydrophilic SO3-Ph-BTP and SO3-Ph-BTBP Ligands

ABSTRACT

Complexation of Pu(IV) and Th(IV) cations by the title ligands – hydrophilic sulfophenyl triazinyl derivatives of bis-triazinyl-pyridine and -bipyridine – was studied in solvent extraction systems containing a TODGA extractant and one of these hydrophilic ligands. Stoichiometries and stability constants of the complexes formed in an acidic (HNO₃) aqueous phase have been determined. The Pu(IV) complexes are significantly stronger than their Th(IV) analogues. Only two complexes of each metal with SO₃-Ph-BTP (1:1 and 1:2) have been detected, and only one (1:1) with SO₃-Ph-BTBP; both numbers being less than expected based on the coordination numbers of the metal ions and on the denticities of the ligands. Possible reasons of this discrepancy are discussed.     

The influence of physico-chemical and operating parameters on the filtration of the precipitate of hydrated Zr(IV) oxide

An experimental investigation of the filtration of the colloidal precipitate of hydrated Zr(IV) oxide is presented. The influence of pH over the range from 3 to 12, of the ageing time of the suspension and of the procedure for the precipitation of hydrated Zr(IV) oxide on the course of its filtration under the constant pressure was studied.     

Synthesis,Characterization, and Analytical Applications of a New Composite Cation Exchange Material Acetonitrile Stannic(IV) Selenite: Adsorption Behavior of Toxic Metal Ions in Nonionic Surfactant Medium

A composite cation exchange material acetonitrile stannic(IV) selenite was prepared under different experimental conditions. The ion exchange capacity of the material was improved from 0.75 to 1.83 meq g^?1 in comparison to its inorganic counterpart, stannic selenite. The material was characterized on the basis of X-ray, TGA, FTIR, and SEM studies. Ion-exchange capacity, pH titration, elution behavior, and distribution studies were also carried out to determine the preliminary ion-exchange properties of the material. Furthermore, it was investigated that this ion exchange material has a good reusability after 8 times regeneration. The sorption behavior of metal ions was studied in nonionic surfactants namely triton x-100 and tween. On the basis of distribution coefficient studies, several binary separations of metal ions viz- Pb²⁺-Th⁴⁺, Ni²⁺-Th⁴⁺, Ni²⁺-Zn²⁺, Cu²⁺-Ce⁴⁺, Al³⁺-Bi³⁺, and Al³⁺Zn²⁺ was achieved on the packed column of this ion exchange material. The practical applicability of this cation-exchanger was demonstrated in the separation of Th⁴⁺ from a synthetic mixture of Th⁴⁺, Ca²⁺, Sr²⁺, Ni²⁺, and Mg²⁺ as well as Cu²⁺ and Zn²⁺ from a brass alloy sample. Thus, all the studies suggest that acetonitrile stannic(IV) selenite has excellent potential for the removal of metal ionic pollutant species from aqueous media effectively.     

Oxo-Titanium(IV) Complex/Polymer Composites—Synthesis,Spectroscopic Characterization and Antimicrobial Activity Test

The emergence of a large number of bacterial strains resistant to many drugs or disinfectants currently used contributed to the search of new, more effective antimicrobial agents. In the presented paper, we assessed the microbiocidal activity of tri- and tetranuclear oxo-titanium(IV) complexes (TOCs), which were dispersed in the poly(methyl methacrylate) (PMMA) matrix. The TOCs were synthesized in reaction to Ti(OR)₄ (R = ⁱPr, ⁱBu) and HO₂CR’ (R’ = 4-PhNH₂ and 4-PhOH) in a 4:1 molar ratio at room temperature and in Ar atmosphere. The structure of isolated oxo-complexes was confirmed by IR and Raman spectroscopy and mass spectrometry. The antimicrobial activity of the produced composites (PMMA + TOCs) was estimated against Gram-positive (Staphylococcus aureus ATCC 6538 and S. aureus ATCC 25923) and Gram-negative (Escherichia coli ATCC 8739 and E. coli ATCC 25922) bacteria and yeasts of Candida albicans ATCC 10231. All produced composites showed biocidal activity against the bacteria. Composites containing {Ti₄O₂} cores and the {Ti₃O} core stabilized by the 4-hydroxybenzoic ligand showed also high activity against yeasts. The results of investigations carried out suggest that produced (PMMA + TOCs) composites, due to their microbiocidal activity, could find an application in the elimination of microbial contaminations in various fields of our lives.     

The Separation of Rhodium and Iridium. II. Chloridation and Chlorination of Iridium(III) and (IV)

Abstract

The chloridation of iridium(III) chloro aquo complexes was studied at different aqueous HCl concentrations and temperatures to determine the optimum conditions which upon chlorination will lead to the most convenient method to produce an aqueous solution which only contains the [IrCl₆]^2? species required for very efficient separation of iridium from rhodium by separating agents like quaternary ammonium species. The interdependency of the two processes of chloridation and chlorination is indicated.     

Adsorption and diffusion of cesium ions in zirconium(IV) iodomolybdate exchanger

Tetravalent metal acid (TMA) salt zirconium(IV) iodomolybdate ion exchanger was chemically synthesized under different conditions and subjected into batch reactor for cesium removal investigation. The properties of synthesized exchangers were characterized using X-ray diffraction (XRD) and thermogravimetric analysis (TGA). Data revealed that the prepared beads are amorphous in nature and thermally stable up to 350 °C. The influences of contact time, pH, ionic strength, and organic acids were investigated. Results illustrated that cesium uptake reached equilibrium within 2 h and it is strongly dependent on ionic strength and nearly independent of pH values. Speciation of cesium ions and their ability to form ternary complexes less adhered to the applied exchangers predominate their adsorption behavior. The prepared exchangers had a good ion-exchange capacity ranged from 7.94 to 9.62 mmol g⁻¹.     

Synthesis and characterization of the first poly(imidazolyl)borate organotin(IV) complex exhibiting a polymeric chain structure

The reaction between SnR_nX_4−n (R=Me, Ph or cy; n=2 or 3) acceptors and sodium tetrakis(imidazol-1-yl)borate, Na[B(im)₄], yields {[B(im)₄]R_nSnCl_4−n−1} compounds. The X-ray crystal structure of [μ-(im)₂B(im)₂SnMe₃] is the first example of a polymeric derivative containing the [B(im)₄]⁻ ligand coordinated in bridging fashion.     

Electrochemical study of cerium(IV) in the presence of ethylenediaminetetraacetic acid (EDTA) and diethylenetriaminepentaacetate (DTPA) ligands

The electrochemical behaviour of the complexation of cerium(IV) with EDTA and DTPA was studied using both cyclic voltammetry (CV) and rotating disc electrode (RDE). The Ce(IV)–DTPA complex at various scan rates gave a linear correlation between the peak potential (E _p ) and square root of scan rate, showing that the kinetics of the overall process was controlled by mass transport. However, when the EDTA ligand was added to the Ce(IV) there was no specific change to the potential peak, i.e. the Ce(IV)–EDTA complex has the same redox potential as the Ce(IV)/(III) couple. Kinetic parameters such as potential, limiting current, diffusion coefficients, transfer coefficient and rate constants were studied. The results from RDE experiments confirmed that the parameters measured by CV are similar under hydrodynamic conditions and can be used to determine the kinetic parameters of the redox couples. The use of DTPA as a ligand for complexation of Ce(IV) gaves more favourable results compared to the Ce–(EDTA) complex reported previously. The results of kinetic studies of Ce(IV)–DTPA complex shows promise as an electrolyte for redox flow battery.     

酒石酸钛(IV)配合物的合成和热性质研究

通过四氯化钛与酒石酸反应，制得了新的固态配合物Ｔｉ２Ｏ２（ＯＨ）２Ｃ４Ｈ４Ｏ６·３Ｈ２Ｏ。用元素分析、Ｘ－射线粉末衍射，ＩＲ和ＴＧ分析确定了产物的组成。ＴＧ和ＤＳＣ研究了它在空气氛围下的热分解特性，计算机求解热分解反应各阶段的活化能Ｅａ，反应级数ｎ、焓变面△ｒＨ和熵变面△ｒＳ。在５５０℃灼烧１小时，可得锐钛型ＴｉＯ２。     

Polymerization of acrylonitrile initiated by Ce(IV)-sucrose redox system: A kinetic study

The polymerization of acrylonitrile (M), initiated by the free radicals formed in situ in the Ce (IV)-sucrose redox system, was studied in aqueous sulfuric acid medium under nitrogen atmosphere in the temperature range of 30–60°C. The rate of polymerization is proportional to [M]^1.0, [R]^0.76, [Ce(IV)]^0.8, and [H⁺]^−0.46. The rate of Ceric ion disappearance and the rate of polymerization R_p have been measured. The effects of some water–miscible organic solvents, surfactants, ionic strength, and complexing agents on the rate of polymerization were investigated. The temperature-dependence of the rate was studied and the activation parameters were computed using the Arrhenius and Eyring plots. A mechanism consistent with the experimental data, involving Ce(IV)-sucrose complex formation, which generates free radicals, is suggested. The chain termination step of the polymerization reaction was determined. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008