Authors:M. Galamboš, P. Suchánek, and O. Rosskopfová
The history of sorption and ion-exchange processes starts with the use of natural materials which properties were discovered
coincidentally and ends with the age of polymer and anorganic—or synthetic sorbents specifically made for a particular project.
Its objectives are focused on sorption of anthropogenic radionuclides originating from nuclear power plant operations (fission,
activation, corrosion products and transuranium elements) on bentonites, zeolites, hydroxyapatites, magnetic sorbent, ferrocyanides,
and silica sorbent. Bentonites from Slovak deposits should be used as part of multi-barrier system in deep geological repository
for spent nuclear fuel and high level radioactive waste. Zeolites are used as molecular sieves, catalysts, ion-exchangers,
sorbents, water softeners, in wastewater treatment, in chemistry industry, buildings. Hydroxyapatite is a suitable sorbent
for heavy metals and radionuclides due to its low water solubility, high stability under reducing and oxidizing conditions,
high specific surface area and good buffering properties. The leaching wastes from the Sereď hydrometallurgical plant represent
a large stock of inexpensive, ready-to-use magnetic sorbent for the decontamination of soil or sediments in their common suspensions,
followed by the magnetic separation and sorbent recycling. Insoluble ferrocyanides of nickel are highly selective sorbents
for heavy alkali metals ions, and therefore can be used to separate cesium from liquid radioactve waste. Silica sorbents modified
with imidazole can be used for the separation of cobalt ions from aqueous solution.
Nickel is a constituent of wide range of construction materials in nuclear industry and their corresponding activation products
are often encountered in low level solid radioactive waste and effluents. The article presents the radiochemical analytical
method for determination of 63Ni in the concrete samples originated from Nuclear Power Plant Mochovce, Slovakia. The sample of concrete was ashed and leached
with aqua regia thereafter hydroxides were precipitated with ammonia solution, leaving Ni in aqueous phase. The next purification
steps included a precipitation as Ni–dimethylglyoxime (DMG) complex, an anionic exchange column and an extraction chromatography
on Nickel resin. The purified 63Ni fraction was mixed with the scintillation cocktail and the mixture was measured by liquid scintillation counting (LSC).
The radiochemical yield of the separation procedure was determined by atomic absorption measurement of stable Ni in the range
of 49–71%. Up to the sample amount of 50 g the detection limit was 0.002 Bq g−1 at counting time 180 min and 95% confidence level.
The sorption of strontium on synthetic hydroxyapatite was investigated using batch method and radiotracer technique. The hydroxyapatite
samples were prepared by a wet precipitation process followed by calcination of calcium phosphate that precipitated from aqueous
solution. Also, commercial hydroxyapatites were used. The sorption of strontium on hydroxyapatite depended on the method of
preparation and it was pH independent ranging from 4 to 9 as a result of buffering properties of hydroxyapatite. The distribution
coefficient Kd was significantly decreased with increasing concentration of Sr2+ and Ca2+ ions in solution with concentration above 1 × 10−3 mol dm−3. The percentage strontium sorption for commercial and by wet method prepared hydroxyapatite was in the range of 83–96%, while
calcined hydroxyapatite was ranging from 10 to 30%. The experimental data for sorption of strontium have been interpreted
in the term of Langmuir isotherm. The sorption of Sr2+ ions was performed by ion-exchange with Ca2+ cations on the crystal surface of hydroxyapatite. Although calcined hydroxyapatite is successfully used as biomaterial for
hard tissues repair, it is not used for the treatment of liquid wastes.
The distribution of strontium between the milk components, i.e., serum, casein micelles, whey and hydroxyapatite was determined.
The sorption on hydroxyapatite was investigated using batch method and radiotracer technique. The aqueous phase comprised
of either milk or whey. The sorption of strontium on hydroxyapatite depended on the method of its preparation and on the composition
of the aqueous phase. The sorption of strontium was increased with an increase of pH. The presence of citrate species resulted
in decrease of the sorption of strontium on hydroxyapatite. The sorption of 85Sr on hydroxyapatite decreased with the increasing concentration of Ca2+ ions. Addition of Ca2+ ions to milk resulted in milk pH decrease. The decrease in pH value after calcium addition to milk is related to exchanges
between added calcium and micellar H+. The average value of strontium sorption on casein micelles in milk with presence of hydroxyapatite was (47.3 ± 5.6) %. The
average value of sorption of 85Sr on casein micelles in milk without the addition of hydroxyapatite was (68.9 ± 2.2) %.
Authors:O. Rosskopfová, M. Galamboš, J. Ometáková, M. Čaplovičová, and P. Rajec
The sorption of copper on synthetic hydroxyapatite was investigated using a batch method and radiotracer technique. The hydroxyapatite
sample prepared by a wet precipitation process was of high crystallinity with Ca/P ratio of 1.688. The sorption of copper
on hydroxyapatite was pH independent ranging from 4 to 6 as a result of buffering properties of hydroxyapatite. The adsorption
of copper was rapid and the percentage of Cu sorption was >98% during the first 15–30 min of the contact time. The experimental
data for sorption of copper have been interpreted in the term of Langmuir isotherm. The sorption of Cu2+ ions was performed by ion-exchange with Ca2+ cations on the crystal surface of hydroxyapatite under experimental conditions. The competition effect of Zn2+, Fe2+ and Pb2+ towards Cu2+ sorption was stronger than that of Co2+, Ni2+ and Ca2+ ions. The ability of the bivalent cations to depress the sorption of copper on hydroxyapatite was in the following order
Pb2+ > Fe2+ > Zn2+ > Co2+ ≈ Ni2+.
Authors:M. Galamboš, M. Osacký, O. Rosskopfová, A. Krajňák, and P. Rajec
Slovak bentonites characterized by good rheological, mineralogical and chemical stability are considered as suitable sealing
barriers for construction of Slovak deep geological repository for high-level radioactive waste and spent nuclear fuel. There
is several Slovak bentonite deposits, bentonites of which have appropriate adsorption properties meeting the geotechnical
requirements for this type of barriers. Study of adsorption properties of bentonites (mainly smectites) is an essential step
for developing the migration model long-lived corrosion and activation products, and fission products of uranium. Nuclear
wastes contain the most important nuclear fission products, β-emitter 90Sr with long half-life, biological half-life and high mobility. The present paper investigates and compares the strontium
adsorption properties of bentonites of different mineral composition consisted mainly of dioctahedral and trioctahedral smectites.
Authors:M. Galamboš, V. Paučová, J. Kufčáková, O. Rosskopfová, P. Rajec, and R. Adamcová
The physical and chemical properties of illitic clay minerals from Slovak deposit suitable for application in engineering
barriers for high level radioactive waste repositories and spent nuclear fuels were studied. The isolation of spent nuclear
fuels and high level radioactive wastes from the outer environment in a deep repository is gained by means of a system of
multiple engineering and natural sealing barriers. Vital segments in a multiple barrier system are clay rocks, of which bentonites
represent the most suitable clay material. Cs-adsorption on fine fractions of adsorbents (bentonites from three Slovak deposits:
Jelšový potok J15, Kopernica K15, Lieskovec L15 and montmorillonite K10) has been studied with using batch of radiometric
techniques. Adsorption parameters have been determined for adsorbent-cesium solution system as a function of contact time
and adsorbate concentration. The influences of pH change, the effect of competitive cations, complex-forming organic chelating
agents on the adsorption of Cs have also been studied.
Authors:M. Galamboš, M. Daňo, O. Rosskopfová, F. Šeršeň, J. Kufčáková, R. Adamcová, and P. Rajec
One of the basic prerequisites for the use of bentonite as engineering barrier in deep geological repositories for radioactive
waste and spent nuclear fuel is their stability against ionizing radiation stemming from radionuclides present in radioactive
waste and spent nuclear fuel. The aim of this study was to compare the changes in the adsorption properties of selected Slovak
bentonites in relation to uranium fission products (137Cs and 90Sr), prior to and after irradiation of bentonites with a 60Co γ-source and specifying the changes in the structure of Slovak bentonites induced by γ-radiation. The changes in irradiated
natural forms of Slovak bentonites and the changes in their natrified analogues and fractions with different grain sizes were
studied from five Slovak deposits: Jelšový potok, Kopernica, Lastovce, Lieskovec and Dolná Ves. The EPR spectra of bentonites
from deposits Jelšový potok and Lieskovec with absorbed doses of 104 and 105 Gy γ-rays showed no changes in the structure of the studied Slovak bentonites. The changes, which in terms of structure destabilization
can be considered insignificant, occurred only in bentonites with absorbed doses of γ-radiation as much as 1 MGy. The absorbed
dose of 1 MGy γ-radiation did not have an effect on the adsorption of cesium on every studied bentonite. Changes that can
also be regarded as insignificant occurred only during strontium adsorption, especially on Fe–bentonite from deposit Lieskovec
and Ca–Mg–bentonite from deposit Jelšový potok, when an increase in the adsorption capacity occurred. Attention should be
paid in further research of this topic which would require carrying out experiments on bentonite samples with absorbed doses
higher by several orders of magnitude.
Authors:M. Galamboš, M. Magula, M. Daňo, M. Osacký, O. Rosskopfová, and P. Rajec
Bentonites which are characterized by good rheological, mineralogical and chemical stability is considered used as sealing
barriers in multibarrier Slovak system of deep geological repository for high-level radioactive waste and spent nuclear fuel.
In Slovak Republic there are several significant deposits of bentonite, which are characterized by appropriate adsorption
properties and meet the geotechnical requirements for this type of barriers. Study of adsorption properties of bentonites
and other smectites is an essential step for developing the migration model long-lived corrosion and activation products,
and fission products of uranium. Nuclear wastes contain the most important nuclear fission products, radioisotopes 134Cs and 137Cs. The present paper investigates and compares the cesium adsorption properties of Slovak and North America bentonites composed
mainly of dioctahedral smectite montmorillonite (J, L, SAz-1 and STx-1) and trioctahedral smectites saponite (SapCa-2) and
Authors:J. Ometáková, P. Rajec, V. Csiba, M. Leporis, M. Štefečka, P. Vlk, M. Galamboš, and O. Rosskopfová
64Cu (T1/2 = 12,7 h, β− 37,1 %, β+ 17,9 %, EC 41 %) is a useful radioisotopes for positron emission tomography radiopharmaceutical. We used the reaction route
64Ni(p,n)64Cu for the 64Cu preparation. A basic disadvantage of this route, a high price of the enriched target material, was eliminated by using
very simple recycling procedure. Compact solid target irradiation system was installed at the end of the external beam line
of the IBA Cyclone 18/9 cyclotron. In this paper, the irradiation of 64Ni target and separation of 64Cu from a target material is described. The separation was achieved by anion exchange chromatography with HCl as a elution
solution. The distribution ratio for different HCl concentrations on Bio-Rad AG1-X8 and elution profile of 64Cu were investigated. 64Cu production rate for 100 mg 64Ni of 99.09 % purity (ISOFLEX) on gold target was 104 MBq/μAh. The activity of the product was checked by ionisation chamber
(Curiementor), gamma spectrometry using a HPGe detector and liquid scintillation counting using the triple-to-double coincidence
ratio method. The separation process of 64Cu was made in a home-made separation module.