Authors:H. Al’tshuler, E. Ostapova, L. Sapozhnikova, and O. Al’tshuler
The thermodynamic characteristics of proton exchange in SO3H groups of a sulfonated network polymer based on cis-tetraphenylmetacyclophanoctol for Na+, Cu2+ cations from aqueous solutions were considered for the first time. Microcalorimetric measurements of the heat effects of
Na+-H+ and Cu2+-H+ exchanges were performed, equilibrium compositions of polymer and solution were determined. The changes of Gibbs energy,
enthalpy and entropy of ion exchange were calculated.
Thermogravimetric data were used to calculate the number of acidic Brnsted sites in lamellar α-titanium (α-TiP), γ-titanium
(γ-TiP), α-zirconium (α-ZrP) and γ-zirconium (γ-ZrP) hydrogenphosphates. The numbers of acidic sites calculated for these
lamellar compounds were 7.81, 5.67, 6.33 and 5.56 for α-TiP, γ-TiP, α-ZrP and γ-ZrP, respectively. These values are in good
agreement with those found through potentiometric titration. The data obtained prove that thermogravimetric measurements can
be used as a reliable analytical tool to follow the ion-exchange capacity of this kind of crystalline lamellar compounds.
Authors:J. Stejskal, J. Soukup, J. Doležal, and V. Kouřím
The use of organic polymers as binding agents for inorganic ion-exchangers has been studied. Poly-vinyl acetate and polystyrene
polymers were applied to ammonium phosphomolybdate and zinc ferrocyanide. The method of preparation and hydromechanical properties
of the resulting materials in ion-exchange columns are described. The materials were used for caesium removal from simulated
Purex high-level radioactive waste solutions. The break-though capacities and results of repeated sorption-elution cycles
Authors:J. Doležal, J. Stejskal, M. Tympl, and V. Kouřím
The possibility of using the sol-gel method for preparation of inorganic ion-exchangers with a silica gel matrix has been
demonstrated on the ammonium molybdophosphate-silica gel (AMP-SG) system. For the preparation of the ion-exchanger a sodium
silicate solution, containing AMP and components to cause gelling to silica gel after increase of the temperature of the solution,
is poured into a hot stirred silicone oil. The solution forms droplets, which are filtered off after their gelling, washed
and dried. Beads containing 65 wt.% of AMP per gram of dry material have been prepared by this method and tested in ion-exchange
columns for caesium removal from nitric acid solutions. Caesium may easily be desorbed with ammonium chloride or nitrate solutions.
The ion-exchanger is suitable for long-time reversible column operation, having not only good chemical, thermal and radiation
stabilities but also good mechanical and hydrodynamic properties and resistance to abrasion. It combines the advantage of
the good kinetics of ion-exchange obtained with microparticles of precipitated inorganic ion-exchanger, with the low flow
resistance of large particles.
A series of mixed sulphates of lead and calcium as well as the polyantimonic acid have been tested for their ability to isolate
strontium from acidic solutions. The sol-gel method was used for preparation of particles with a silica gel matrix. Both polyantimonic
acid and lead-calcium sulphate were found to be promising ion-exchangers.
Authors:I. Szilágyi, J. Madarász, G. Pokol, F. Hange, G. Szalontai, Katalin Varga-Josepovits, and A. Tóth
This paper discusses the changes in the structure and thermal reduction of nanosize hexagonal ammonium tungsten bronze (HATB),
(NH4)0.33−xWO3−y, which were caused by K+ ion exchange (doping) and studied by XRD, XPS, 1H-MAS NMR, FTIR, SEM and TG/DTA-MS. Comparison of the cell parameters of undoped and doped HATB revealed that both a and c cell parameters decreased after the ion exchange reaction, which showed that smaller K+ ions partly replaced the larger NH4+ ions in the hexagonal channels of HATB. After the reaction, from the hexagonal channels less NH3 evolved, which also supported the incorporation of K+ ions into the hexagonal channels.
Authors:S. D. Sharma, K. G. Varshney, and S. C. Mojumdar
Inorganic ionexchangers have been of great interest for the last six decades, zirconium(IV) phosphate being the most extensively studied material [ 1 , 2 ]. Next to this are the tin(IV)-based materials, due to
Authors:P. Mayankutty, N. Pillai, S. Shinde, and M. Nadkarni
Studies on the partitioning of plutonium from 30% TBP by ion-exchange absorption on macroporous cation exchanger Amberlyst-15
have been described. Detailed loading experiments indicate that the resin absorbs plutonium in preference to uranium from
loaded organic phase at low organic phase acidities (around 0.2M). Absorption behaviour of some fission products on the resin
in 30% TBP is also reported. Possibility of using this procedure as an alternate method for plutonium partitioning from IAP
stream of Purex process has been discussed.