Authors:K. Varshney, V. Jain, A. Agrawal, and S. Mojumdar
Pyridine based zirconium(IV) phosphate (PyZrP)
and tin(IV) phosphate (PySnP) have been synthesized as new and novel intercalated
ion exchangers. These materials have been characterized using X-ray, IR spectra,
TG, DTG and DTA studies in addition to their ion exchange capacity, elution,
pH titration, concentration and distribution behaviour. The distribution studies
towards several metal ions in different media/concentrations have suggested
that PyZrP and PySnP are selective for Hg(II) and Pb(II), respectively. As
a consequence some binary separations of metal ions involving Hg(II) and Pb(II)
ions have been performed on a column of these materials, demonstrating their
analytical and environmental potential.
Authors:G. K. Bratspies, J. F. Smith, J. O. Hill, and P. J. Derrick
A new tin dithiocarbamate containing sulphur bridges, di-μ-sulphidobis [bis(N,N-diethyldithiocarbamato)tin(IV)], has been isolated from the thermal decomposition of tetrakis(N,N-diethyldithiocarbamato)tin(IV). A dimeric structure is proposed on the basis of results from mass spectrometry, infrared spectroscopy, thermal analysis and vapour pressure osmometry.
Authors:N. Burham, S. Abdel-Halim, I. El-Naggar, and M. El-Shahat
Tin(IV) antimonate with different Sb/Sn molar ratios has been prepared. The characterization of the product materials was carried out using X-ray diffraction pattern, themal analysis and infrared spectra. The saturation capacities of sodium and cesium were found to increase with Sb/Sn molar ratios. TheKd values on thermal treatment of tin(IV) antimonate, as a cation exchanger, have been measured for some heavy metal ions in the temperature range of 50–400 °C. The maximum adsorption of 10–4M of the metal ions studied was obtained at 400 °C. The selectivity sequence was Eu3+>Co2+>Sr2+>Cs+ for the sample heated up to 400 °C. No adsorption was observed on the sample heated at 700 °C because of the formation of SnO2 and Sb6O13.
Column chromatographic technique has been utilized to study the column performance of uranyl ion separation on tin(IV) antimonite
hydrous oxide matrix. Different flow rates were applied, at 0.6 ionic strength and pH 3, to evaluate the effect of different
flow rate on column breakthrough behaviour. Van Demeeter equation was used to emphasize the optimum column conditions. High
equivalent to theoretical plate, breakthrough capacity (Q0.5) were also calculated.
Authors:J. Sedláček, A. Gosman, P. Podhájecký, and J. Tarasová
This paper is concerned with the study of isotope exchange reaction between Sn(II) and Sn(IV) in hydrochloric acid solutions.
The kinetics of the exchange reaction of tin in these solutions were studied by extraction of Sn(IV)-hydroxyquinolate into
chloroform.113Sn tracer, initially in the Sn(IV) state, was used. The rate of exchange reaction was determined at 22°C in a wide range of
hydrochloric acid concentrations (2.8–12M). The dependence of the exchange rate on the concentration of chloride and hydrogen
ions in these solutions (ionic strength: I∼8 and I∼12) are given. The activation energy dependence on chloride ion concentration
at I∼12 was determined. The possible mechanism of the exchange reaction between tin(II) and tin(IV) is discussed on the basis
of these data.
Authors:A. Bhaduri, B. Bhushan, K. Pandeya, and K. Kar
Kinetics of the exchange reaction of cadmium(II)-ammine complex ion using radio-active isotope115Cd in the same chemical form in hydrous oxides of zirconium(IV), silicon(IV) and tin(IV) has been studied. It has been found
that the major contribution in the overall exchange process is from the surface of the exchanger particles. It has also been
found that the rate of exchange follows the order: hydrous ZrO2>hydrous SnO2>hydrous SiO2
1,10-phenanthroline (phen), 2,2′-bipyridyl (bipy), pyridine (py) and 4-picoline (4-pic) complexes of dibutyltindichloride (Bu2SnCl2) and dimethyltindichloride (Me2SnCl2) were synthesized. The complexes were characterized with the help of elemental analyses, IR spectra and thermal analyses. The complexes were found to have the compositions [Bu2SnCl2·phen], [Bu2SnCl2·bipy], [Me2SnCl2·phen], [Me2SnCl2·bipy], [Me2SnCl2·2py] and [Me2SnCl2·2(4-pic)]·H2O. All these complex compounds appeared to posses octahedral structures. Thermodynamic parameters, such as activation energyEa* enthalpy change ΔH and entropy change ΔS, for the dehydration and sublimation of the complexes were evaluated using some standard methods.
Authors:M. Ganzerli Valentini, R. Stella, and L. Maggi
A novel type of tin oxide and its cation exchange properties are described. The preparation of the oxide is rather unusual and consists in the precipitation of SnO·xH2O in the presence of sodium nitroprusside and its digestion in the presence of sodium nitrite. The final product is a partially reduced tin dioxide (PRTD) with one out of eight atoms of metal in the lower oxidation state of +2 and a great part of the bound water hydrogen replaced by sodium. Usual applications of commercially available tin dioxide exchangers can be extended to PRTD with remarkable advantages.
Authors:C. Parnau, R. Olar, M. Badea, and A. Kriza
The complexes of the type SnCl4(HL)·EtOH
and SnCl2L2 (HL 1
: the Schiff base resulted in 1:1 condensation of isatin and aniline; HL 2
: the Schiff base resulted in 1:1 condensation of isatin and p-toluidine)
have been synthesized and characterized. The thermal analysis of the new ligands
and complexes has evidenced the thermal intervals of stability and also the
thermal effects that accompany them. The Schiff bases thermal transformations
consist in phase transitions, Carom–N bond cleavage
and thermolysis processes. The different nature of the complexes generates
their different thermal behaviour. The complexes lead in three steps to SnO2
and in all cases the Schiff bases degradation generates a pyrrolidone-coordinated
derivative. As for the SnCl4(HL)·EtOH complexes,
the SnCl4 formed during the last step is involved in
two competitive processes, one consists in their volatilisation while the
other one leads to SnO2. As result the SnO2
residue is smaller than the theoretically expected.