7 resultados para Ion removal

em Cochin University of Science


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A set of six new polystyrene anchored metal complexes have been synthesized by the reaction of the metal salt with the polystyrene anchored Schiff base of vanillin. These complexes were characterized by elemental analyses, Fourier transform infrared spectroscopy, diffuse reflectance studies, thermal studies, and magnetic susceptibility measurements. The elemental analyses suggest a metal : ligand ratio of 1 : 2. The ligand is unidentate and coordinates through the azomethine nitrogen. The Mn(II), Fe(III), Co(II), Ni(II), and Cu(II) complexes are all paramagnetic while Zn(II) is diamagnetic. The Cu(II) complex is assigned a square planar structure, while Zn(II) is assigned a tetrahedral structure and Mn(II), Fe(III), Co(II), and Ni(II) are all assigned octahedral geometry. The thermal analyses were done on the ligand and its complexes to reveal their stability. Further, the application of the Schiff base as a chelating resin in ion removal studies was investigated. The polystyrene anchored Schiff base gave 96% efficiency in the removal of Ni(II) from a 20-ppm solution in 15 min, without any interference from ions such as Mn(II), Co(II), Fe(III), Cu(II), Zn(II), U(VI), Na , K , NH4 , Ca2 , Cl , Br , NO3 , NO2 ,and CH3CO2 . The major advantage is that the removal is achieved without altering the pH.

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This paper reports the synthesis of a series of six new polystyrene anchored metal complexes of Co(II), Fe(III), Ni(II), Cu(II), Zn(II), and dioxouanium(VI) using the polystyrene anchored Schiff base of 2-nitrobenzaldehyde and the corresponding metal salts. The metal salts used were anhydrous FeCl3, CoCl2 Æ 6H2O, Ni(CH3COO)2 Æ 4H2O, Cu(CH3- COO)2 Æ H2O, Zn(CH3COO)2 Æ 2H2O, and UO2(CH3COO) Æ 2H2O. Physico chemical characterizations have been made from diffuse reflectance and vibrational spectra, elemental analysis, magnetic measurements, and TG studies. The elemental analysis suggest a 1:2 metal:ligand ratio when the complexation has carried out at 70 C for about 12 h reflux. The ligand is monodentate and coordinates through the azomethine nitrogen. The Fe(III), Co(II), Ni(II), and Cu(II) complexes are all paramagnetic whereas Zn(II) and U(VI) are diamagnetic. Zn(II) is assigned a tetrahedral structure, Cu(II) and Co(II) are assigned a square planar structure and Fe(III), Ni(II), and U(VI) are all assigned an octahedral structure. The polystyrene anchored ligand has been developed as an excellent reagent for the removal of Cu(II). Optimum conditions have been developed for the removal of metal ion from solutions by studying the effect of change of concentration of metal ion, ligand, effect of pH, time of reflux, and interference effect of other ions. It was found that within a span of 20 min it is possible to remove 90% of the metal ion from a 30 ppm metal ion solution in the pH range 4–5.5.

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Salicylaldehyde Schiff base of amino-methylated polystyrene has been developed as a novel reagent for the removal of Fe(III) from solutions. The selectivity of the metal ion uptake over a wide range of different concentrations of metal ion, effect of pH, ligand concentration and the influence of other foreign ions were studied. A very good selectivity was achieved for the removal of the ion. It was found that 0.01 g of the ligand was sufficient to achieve about 96% removal of the metal ion in terms of concentration (ppm) from a 30 ppm solution in acidic pH.

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Polymer supports are efficient reagents,substrates and catalysts and they are extensively used for carrying out reactions at controlled rates.Tailor-made polymer supports are highly versatile which have opened an excellent area of research.Now polymer supported chemistry is being exploited at an amazing rate and it seems to join the routine world of organic synthesis.Polymer supported ligands are found to be efficient complexing agents whose high selectivity enables the analysis and removal of heavy metal ions which are toxic to all the living organisms of land and sea.polymer supported membranes function as ion selective potentiometric sensors which allow the exchange of specific ions among other ions of the same charge.In this investigation three series of polymeric schiff bases and three series of metal complexes have been prepared.An attempt is done to develop optimum conditions for the removal of heavy metal ions using polymeric schiff bases.A novel copper sensor electrode have also been prepared from polymer supported metal complex.

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Polymer supports and polymeric complexes are highly versatile and they are successfully employed as efficient reagents, substrates and catalysts. Recently there observed a growing interest in the synthesis of tailor-made polymer supports and functionalized polymers for the preparation of metal complexes for various applications. They have the combination of properties due to the macromolecular structure as well as due to the reactivity of the functional group. An interesting feature of functional polymers is their affinity towards metal ions. Therefore the synthesis, characterization and application of such polymeric complexes have great scientific and analytical importance. In this investigation three series of polymeric complexes of transition metal ions are prepared from three schiff bases. All the complexes and polymeric schiff bases were characterized by analytical, spectral and thermal methods The thesis consist of six chapters. The first chapter contains an introduction and a brief review on application of polymer supports, polymer supported ligands and complexes. The second chapter gives the details of reagents and instruments used and the procedure adopted for the preparation of ligands and complexes. The third chapter explains the methods employed for characterization and the results are also discussed. The fourth chapter gives a detailed study of metal ion removal using ligands whereas the fifth chapter describes the development of the Cu” ion sensor electrode. The sixth chapter is the summary of the thesis and references are presented at the end.

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As the application of polymeric complexes is enormous, there exists a continuing interest in the synthesis and characterization of these complexes. The synthetic and characterization parts are very important in an academic point of view. Further in an application point of view also polymeric ligands/complexes are gaining attention.The thesis is divided in to six chapters, in which the first chapter gives an introduction along with a brief review on polymeric ligands/ complexes. The second chapter explains the different procedure adopted for the whole work along with the details of the reagents/ instruments used. The third chapter gives a report of the detailed study regarding the synthesis and characterization of eighteen complexes. While the fourth chapter is a report of the ion removal studies using three polymeric ligands, the fifth chapter explains the development of a polymeric complex as ion selective electrode material for the fabrication of a CC ion selective electrode. The sixth chapter presents the summary and tables, figures and references are given separately at the end.

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Ion-exchange chromatography has emerged as a practical and rapid method of separation and analysis. A review of literature on chelating resins reveals that eventhough investigations on highly selective resins are intensively pursued from early 1940s, such resins are still insufficiently used in analytical chemistry and process technology. This is mainly due to the complexity of their synthesis and high cost. In this context, it is worthwhile to develop novel chelating resins which are specific or at least selective towards a group of metal ions. Synthesis, characterization and analytical applications of two such resins are presented in this thesis.