Authors:K. Varshney, S. Agrawal, K. Varshney, U. Sharma, and S. Rani
Effect of various doses of gamma radiation on the ion-exchange capacity, distribution coefficient values, elution behaviour, pH titration and infrared spectra of some thermally stable inorganic ion exchangers has been studied systematically. No change has been observed in the ion-exchange capacity, elution behaviour and the infrared spectra of the materials irradiated up to a total dose of 3·108 rad, while, a change has been observed in their pH-titration and distribution behaviour.
Authors:H. Rathore, K. Ishratullah, C. Varshney, G. Varshney, and S. Mojumdar
Copper diethyldithiocarbamate, cadmium diethyldithiocarbamate, lead diethyldithiocarbamate, nickel diethyldithiocarbamate
and zinc diethyldithiocarbamate have been synthesized. They have been characterized using TG, DTA, IR spectroscopy, X-ray
and atomic absorption spectrophotometry. The thermal conversion of the compounds is 54.36–88% at 1000°C. Their solubility
in sodium hydroxide, mineral acids, organic solvents, distilled water and salts solution has been measured. Fungicidal activity
of the dithiocarbamates has been tested by well or cup diffusion method using five fungi species. Their activity has also
been tested by broth dilution method using six bacterial species. Minimum Inhibitory Concentration (bactericidal) is 6.25–25.00
A new hybrid ion exchanger, Triton X-100 based tin(IV) phosphate (TX-100SnP) has been synthesized and characterized by ion
exchange and physico-chemical methods such as ion exchange capacity, elution and concentration behaviour, IR, X-ray, TG/DTA
and elemental analysis. Its adsorption behaviour has also been studied for some alkaline earths and heavy metal ions in different
acidic media. It has been found generally more selective for metal ions as compared to tin(IV) phosphate prepared earlier.
For Pb(II), Hg(II) and Fe(III) its selectivity has been found to be exceptionally good. On this basis, some binary separations
have been performed involving these metal ions. Thermal studies show a high thermal stability of the material. It retains
54.54% of its i.e.c. at 200�C and 27.27% at 300�C.
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.
A new phase of the hybrid fibrous ion exchanger, pyridine based cerium(IV) phosphate (PyCeP), has been synthesized in the
form of a sheet like paper by mixing ceric sulphate, phosphoric acid and pyridine in a particular ratio to get the material
of the optimum ion exchange characteristics. This material has been characterized with the help of ion exchange capacity,
elution and concentration and pH titrations behaviour in addition to some physicochemical studies like X-ray diffraction,
IR, TG, DTG and SEM studies. The SEM study confirms the fibrous nature of the material while amorphous nature is revealed
by its X-ray spectrum.
Authors:M. Drábik, L. Gáliková, K. Varshney, and M. Quraishi
The applicability of MDF synthesis procedure, the coincidence of the interfacial cross-linking and the moisture resistance
of MDF-related mixes based on two industrial Portland cements (CEM I, CEM II) and poly-P are reported. The knowledge of the
moisture resistance of synthesized material is of paramount importance; two independent experimental methods confirmed that
the moisture resistance of MDF cements based on CEM I (or CEM II) with 5% of poly-P achieves sufficient levels at 50% RH and
at ambient values of RH. The results of thermal analysis are directly related to the former knowledge on the appearance and
role of cross-links in the interfacial zone of MDF cements.
Authors:S. D. Sharma, K. G. Varshney, and S. C. Mojumdar
A number of silicon-based inorganic ion exchangers were synthesized under different conditions of preparation. The original and regenerated ion exchange capacities (IECs) were determined. Thermal stability of these materials was investigated in the temperature range of 40–800 °C. The gain/loss of IEC was studied as a function of temperature. These exchangers show a higher IEC and its retention to a considerable extent at elevated temperatures when compared to that of corresponding ion exchangers which do not contain silica. The thermogravimetric curve shows greater percent mass loss in H+ form of the exchanger than in K+ form. Dehydration studies seem to throw some light on the state of water molecules present in various samples. The empirical formula and the tentative structure for stannic arseno silicate have also been proposed.
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.