Pyridine based thorium(IV) phosphate hybrid fibrous ion exchanger

Pyridine based thorium(IV) phosphate (PyThP) has been synthesized by drop-wise addition of the thorium(IV) nitrate with constant stirring into a mixture of pyridine and phosphoric acid. This material has been characterized using X-ray, IR spectra, TG, DTG and SEM studies in addition to its ion exchange capacity, elution and pH titrations. The material has been found amorphous and fibrous in nature on the basis of X-ray diffraction and SEM studies. TG has revealed the changes incurred in the material on thermal treatment and IR spectral studies have shown the presence of various groups in its structure.     

Pyridine based cerium(IV) phosphate hybrid fibrous ion exchanger

Both temperatures, T _C, (T _C —Curie temperature) and heat of the phase transition: ferroelectric-paraelectric, ΔH, in the Ba_xSr_1−xTiO₃ materials have been studied by means of the microcalorimetric method. The determined parameters were verified by either temperature dependence of the dielectric permittivity (Curie-Weiss law) or thermodynamic method. The effect of strontium content on T _C has been discussed. It was found that microcalorimetry is useful tool studying phase transition phenomena in ferroelectric perovskites.     

Synthesis and ion exchange behaviour of polyaniline Sn(IV) arsenophosphate: a polymeric inorganic ion exchanger

Incorporation of a polymer material into an inorganic ion exchanger provides a class of hybrid ion exchangers with a good ion exchange capacity, high stability, reproducibility and selectivity for heavy metals. Such a type of ion exchanger ‘polyaniline Sn(IV) arsenophosphate’ has been synthesized by mixing polyaniline into inorganic material. This material is characterized using X-ray, IR, TGA studies in addition to ion exchange capacity, pH-titration, elution and distribution behaviour. On the basis of distribution studies, the material has been found to be highly selective for Pb(II). Kinetic study of exchange for the metal ions has been performed and some physical parameters such as self diffusion coefficient D₀, energy E_a and entropy ΔS* of activation have been determined.     

Pectin based cerium (IV) and thorium (IV) phosphates as novel hybrid fibrous ion exchangers synthesis,characterization and thermal behaviour

Summary Pectin based cerium (IV) and thorium (IV) phosphates have been synthesized as new phases of hybrid fibrous ion exchangers. Both materials were characterized using X-ray diffraction, infrared (IR) spectra, thermogravimetric analysis (TG), differntial thermogravimetry (DTG), differntial thermal analysis (DTA) and scanning electron microscopy (SEM), as well as the determination of their ion exchange capacity, elution and pH titration. The X-ray study reveals the amorphous nature of the materials, while SEM studies confirm the fibrous nature of the materials. The thermal studies of these materials indicate that both of them are highly stable on heating as they retain about 97% of their ion-exchange capacity (i.e.c.) on heating up to 100°C and about 81% on heating up to 200°C.     

Surfactant assisted preparation and characterization of carboxymethyl cellulose Sn(IV) phosphate composite nano-rod like cation exchanger

Carboxymethyl cellulose Sn(IV) phosphate composite nano-rod like cation exchanger with diameter in the range of 20–40 nm, length in the range of 100–150 μm and particle size in the range of 21–38 nm have been successfully prepared by surfactant assisted sol–gel method. Scanning electron microscopy, transmission electron microscopy, X-ray powder diffraction, fourier transform infra red spectroscopy and thermogravimetric analysis-differential thermal analysis studies were carried out to study the structure and morphology of this composite nano-rod like cation exchanger. Freundlich adsorption isotherm is well fitted for the adsorption of pyridine on the surface of this composite nano-rod like cation exchanger. The thermodynamic parameters such as Freundlich constant, thermodynamic equilibrium constant (K ₀), standard free energy changes (ΔG ⁰), standard enthalpy changes (ΔH ⁰) and standard entropy changes (ΔS ⁰) have been evaluated. These parameters indicated that the adsorption of pyridine on the surface of composite nano-rod like cation exchanger was feasible, spontaneous and exothermic in nature which suggests for the potential application of pyridine removal from water.     

Synthesis, characterization and metal adsorption properties of the new ion exchanger polymer 3-n-propyl(4-methylpyridinium) silsesquioxane chloride

The preparation and anion exchange properties of 3-n-propyl(4-methylpyridinium) silsesquioxane chloride polymer are described. This new polymer was prepared by the sol-gel processing method and is designated as SiPic+Cl-. It is insoluble in water and showed an anion exchange capacity of 1.46x10(-3) mol g-1. The adsorption isotherms of ZnCl2, CdCl2 and HgCl2 were determined from aqueous solutions and the adsorption equilibria simulations fit the model of fixed bidentate centers with the absence of lateral interactions and energetic heterogeneity between them. The metal ions diffuse into the solid solution interface and are dominantly present as MCl2-(4) species for Zn(II), MCl(2-)4 and MCl-3 species for Cd(II) and MCl-3 species for Hg(II).     

Separation of Cr(III) from Cr(VI) by Triton X-100 cerium(IV) phosphate as a surface active ion exchanger

Triton X-100 cerium(IV) phosphate (TX-100CeP) was synthesized and characterized by using IR, X-ray, TGA/DT and the elemental analysis. The chemical stability of TX-100CeP versus the different concentrations of HCl acid was studied before and after its exposure to the radiation dose (30 K Gray). The effect of HCl concentration on separation of Cr(III) from Cr(VI) by using TX-100CeP as surface active ion exchanger was also studied. A novel method was achieved for the quantifying of Cr(III) and Cr(VI) ions by using the high-performance liquid chromatography (HPLC) at wavelength 650 nm, a stationary phase consists of reversed phase column (Nucleosil phenyl column; 250 × 4.6 mm, 5 μm), and a mobile phase consists of 0.001 M di-(2-ethylhexyl) phosphoric acid (DEHPA) in methanol:water (70:30 v/v). The retention times were 7.0 and 8.5 min, for the Cr(III) and Cr(VI), respectively. The exchange capacity of Cr(III) was quantified (2.1 meq/g) onto the TX-100CeP.     

Synthesis and characterization of fluorescent pyrrolyldipyrrinato Sn(IV) complexes

A series of neutral, 5-coordinate pyrrolyldipyrrinato Sn(IV) complexes have been synthesized via reaction of a pyrrolyldipyrrin, or its corresponding hydrochloride salt, with dibutyltin or diphenyltin oxide. The complexes are structurally unique in that all three nitrogen atoms of the pyrrolyldipyrrinato ligand bind to the tin center, making these complexes the first examples of pyrrolyldipyrrins behaving as LX(2) ligands. The complexes are highly fluorescent, exhibiting fluorescence quantum yields between 0.28 and 0.61, and display interesting preliminary biological activity.     

Synthesis, characterization and ion-exchange properties of a new and novel ‘organic-inorganic’ hybrid cation-exchanger: Nylon-6,6, Zr(IV) phosphate

Organic-inorganic hybrid materials enable the integration of useful organic and inorganic characteristics within a single molecular-scale composite. Unique ion-exchange properties of these types of materials have been observed, and many others can be envisioned for this promising class of materials. In this paper, we describe the ion-exchange and physico-chemical properties of one family of self-assembling organic-inorganic hybrid based on nylon-6,6, framework with Zr(IV) phosphate an inorganic ion-exchanger. The physico-chemical properties of this hybrid material were determined using atomic absorption spectrophotometry (AAS), CHN elemental analysis, ICP-MS, UV-vis spectrophotometry, FTIR, TGA-DTA and scanning electron microscope (SEM) studies. Ion-exchange capacity (IEC), thermal stability and distribution behavior, etc. were also carried out to understand the cation-exchange behavior of the material. On the basis of distribution studies, the material was found to be highly selective for Hg(II), a highly toxic environmental pollutant. Its selectivity was examined by achieving some important binary separations like Hg(II)-Mg(II), Hg(II)-Zn(II), Hg(II)-Fe(III), Hg(II)-Bi(III), etc. Thus, the relatively new field of “organic-inorganic” hybrids offers a variety of exciting technological opportunities to decrease the environmental pollution.     

Synthesis and characterization of semicarbazone metal complexes of Sn(IV) and Zr(IV)

Three semicarbazonyl ligands were synthesized and used to form six novel organometallic complexes with Ph2SnCl2 and Cp2ZrCl2. All these complexes were characterized by IR,1H NMR,MS and elemental analysis.     

Synthesis,characterization, and electroanalytical studies of Pb2+-selective polypyrrole-Zr(IV) phosphate ion exchange membrane

Journal of Solid State Electrochemistry - Polypyrrole-Zr(IV) phosphate (PPyZP) composite cation exchange material was synthesized by chemical oxidative polymerization of pyrrole with the help of...     

Synthesis, characterization, and application of titanate nanotubes for Th(IV) adsorption

Titanate nanotubes (TNTs) have been synthesized by a hydrothermal method using rutile TiO₂ powder as titanium source. The determination of the structure and morphology was characterized by XRD, FTIR, SEM and TEM. The results indicate that the TNTs successfully synthesized under hydrothermal conditions of 150 °C. The adsorption of Th(IV) on TNTs was studied as a function of contact time, pH values, ionic strength, initial Th(IV) concentration and temperature under ambient conditions by using batch technique. The results indicate that adsorption of Th(IV) on TNTs is strongly dependent on pH values, but weakly dependent on ionic strength; Adsorption kinetics was better described by the pseudo-second-order model. The adsorption isotherms are simulated by Langmuir and Freundlich models well. ΔG°, ΔH° and ΔS° free energy were calculated from experimental data, The results indicate that the adsorption of Th(IV) on TNTs is an endothermic and a spontaneous process, and increases with increasing temperature. The adsorption of Th(IV) on TNTs is mainly dominated by chemical sorption or surface complexation.     

Synthesis,characterization, and insecticidal activity of new tin (IV) complexes

A three-component reaction of dimethyltin dibromide with imidazo[1,2-a]pyridine, pyridine derivatives, or isoquinoline and allyl bromide in refluxing ethanol affords the ionic complex, bis(1-allylcycloiminium) dimethyltetrabromostannate (II). The reaction involves N-allylation of cycloimine accompanied by the coordination of two bromide ions with the tin atom of dimethyltin dibromide. The complexes have been characterized by infrared and ¹H NMR, ¹³C NMR, and ¹¹⁹Sn NMR studies. The X-ray crystal structure analysis of a complex reveals the tin atom to be hexacoordinated and the dimethyltetrabromostannate (II) anion having octahedral geometry. Some of the complexes tested for their insecticidal activity are found to exhibit strong activity against Tribolium castaneum insect with LC₅₀ ranging from 0.4 to 0.8 ppm.     

Synthesis and characterization of zirconium(IV) iodovanadate and its use as electron exchanger

Samples of zirconium(IV) iodovanadate have been synthesized under varying mixing ratios by adding a mixture of aqueous solution of 0.1 M potassium iodate and 0.1 M sodium metavanadate to aqueous solution of 0.1 M zirconium oxychloride at pH 1. The ion exchange capacity of the material for Na⁺ ion was found to be 2.20 meq g⁻¹ of dry exchanger. The material has been characterized on the basis of chemical composition, FTIR and TGA. The chemical stability of the product has been checked in neutral, acidic and basic media. The product has been used as electron exchanger. The oxidation of Fe(II), Sn(II), ascorbic acid and thioglycolic acid was achieved by batch-equilibrium technique successfully. The maximum redox capacity of the exchanger has been found to be 4.20 meq g⁻¹ of exchanger by column process.     

Synthesis and characterization of carboxylate complexes of Sn(IV) porphyrin monomers and oligomers

Most of the porphyrin-recognition chemistry we have investigated previously has centred on kinetically labile metal-ligand interactions, such as Z-N and Ru-N. Our interest in the broader scope of molecular recognition required a metal with the ability to specifically recognise non-nitrogen-based ligands, with a significantly different binding interaction to distinguish it from nitrogen-based analogues. In this report we describe interactions of Sn(IV) porphyrins that bind oxygen-based ligands and for which the Sn(IV)bond;O bond is in slow exchange on the NMR timescale. A series of carboxylate complexes is employed to highlight the structural/geometric features of porphyrin monomers and cyclic oligomers. Where more than one porphyrin unit is present in a molecular scaffold, we report the effect of carboxylate binding on the complex when the two porphyrins contain different metals (typically Sn(IV) and Zn(II)). The unexpected spectroscopic and structural properties of the Sn(2)(9-anthroic acid)porphyrin dimer are also reported.     

Spectrophotometric Determination of Rhenium(IV) with Thiocyanate,TX-100 and N,N′-Diphenylbenzamidine

A spectrophotometric method to determine rhenium(IV) at trace level is based on the extraction of Re(IV)-SCN^? complex in sulphuric acid media with N,N′-diphenylbenzamidine(DPBA) in presence of a non-ionic surfactant triton X-100 (TX-100) in chloroform. The complex shows maximum absorbance at 435 nm with amolar absorptivity value of 4.24 × 10⁴ L mol^?1 cm^?1 at an acidity range 3.5-6.5 M H₂SO₄. The method followed Beer's Law for the system Re(IV)-SCN^?(TX-100)-DPBA upto 4.0 μg Re(IV) mL^?1. The detection limit of the method is 5 ppb. None of the tested foreign ions, except molybdenum(VI), interfere with the determination of rhenium. The interference due to molybdenum could effectively be removed by prior precipitation with oxine. The effect of various analytical parameters on the extraction of the metal are discussed.     

Kinetic studies of uranium(VI) adsorption on a composite ion exchanger

In this paper, we studied the continuous adsorption of uranium on a composite ion exchanger. The experimental study was carried out at optimum conditions of uranium uptake found in the previous study. For these conditions first the adsorption isotherm was determined. This isotherm shows non-linear sorption according to the Langmuir model. Then we investigated uranium adsorption at different time intervals at temperatures of 30°C and 60°C, respectively.     

Synthesis, characterization, and catalytic properties of new half-sandwich zirconium(IV) complexes

A number of new half-sandwich zirconium(IV) complexes bearing N,N-dimethylaniline-amido ligands with the general formula Cp*ZrCl(2)[ortho-(RNCH(2))(Me(2)N)C(6)H(4)] [R = 2,6-Me(2)C(6)H(3) (1), 2,6-(i)Pr(2)C(6)H(3) (2), (i)Pr (3), (t)Bu (4)] were synthesized by the reaction of Cp*ZrCl(3) with the corresponding ortho-(Me(2)N)C(6)H(4)CH(2)NRLi. All new zirconium complexes were characterized by (1)H and (13)C NMR, elemental analyses and single crystal X-ray diffraction analysis. The molecular structural analysis reveals that the NMe(2) group does not coordinate to the zirconium atom in all cases. Complexes 1-4 all have a pseudo-tetrahedral coordination environment in their solid state structures and adopt a three-legged piano stool geometry for the zirconium atoms with the amide N atom and the two Cl atoms being the three legs and the Cp* ring being the seat. Variable-temperature (1)H NMR experiments for all complexes 1-4 were performed to investigate the possible intramolecular interaction between the N atom in the NMe(2) group and the central zirconium atom in solution. Upon activation with Al(i)Bu(3) and Ph(3)CB(C(6)F(5))(4), complexes 1-4 all exhibit moderate to good catalytic activity for ethylene polymerization and copolymerization with 1-hexene, producing linear polyethylene or poly(ethylene-co-1-hexene) with moderate molecular weight and reasonable 1-hexene incorporation.     

Synthesis,composition and ion exchange properties of Sn(IV) and Cr(III) arsenophosphates: separation of metal ions

This paper deals with the synthesis of the arsenophosphates of various metals. The chemical composition, ion exchange capacity, thermal stability, concentration curves, elution curves, pH-titrations and IR studies have been performed on two materials, namely, Sn(IV) arsenophosphate and Cr(III) arsenophosphate. Their utility has been established by achieving four binary separations of industrial importance such as CuNi, FeCu, FeNi and CoNi on columns.