Soil column experiments have been conducted to treat liquid wastes from hospitals containing125I. Three sorbent samples of laterite clay materials with different contents of iron oxides (goethite, -FeOOH) and hydroxides were used to sorb anionic iodate. Post-treatment on effluent wastes with sodium hypochlorite (redox reagent) oxidized the iodide to the desirable iodate ion. Effluent pH after treatment ranges between 4.8 to 5.8, which does not vary much from the initial effluent pH of 4.5 before treatment. Results show that 90 to 97% sorption of iodine radionuclides with a decontamination factor ranges between 10–32 was obtained after the first two hours of experiments. Concentration has decreased from the initial 10 Bq/ml to concentration ranges of 0.3 to 0.9 Bq/ml. Batch experiments conducted using different sorbent masses of soils, show that there was a drop in sorption as the mass of soils fell below approximately 0 to 0.25 g. The sorption remains constant with the soil mass above 0.25 g. Another batch experiment using a different concentration shows that the adsorption capacity of the laterite soil was 1.1 Ci/g. The adsorption is about 96% with a distribution coefficient of 1170.
Authors:Durga Parajuli, Koichi Hirota, and Noriaki Seko
Aiming the selective recovery of palladium from high level radioactive liquid waste (HLW), a chelating thiamide type sorbent,
CWP–TU, was prepared by the modification of Japanese cedar wood powder (CWP). Convection oven and microwave heating were separately
used for modification purpose and found that microwave heating is more effective over oven heating. CWP–TU was extensively
studied for the adsorption of Pd(II) from nitric acid medium. The batch test showed that nitric acid concentration of 3 M
or higher is favorable for Pd(II) loading. Consistent adsorption of Pd(II) under gamma irradiation condition demonstrated
the feasibility of using CWP–TU in real HLW. Also, Pd(II) only adsorption from simulated HLW solution verified the palladium
only selectivity of the sorbent as well as the lack of influence of coexisting metal ions on its affinity toward Pd(II). CWP–TU
holds maximum Pd(II) loading capacities of 0.98 mol/kg at 30 °C and 1.04 mol/kg under gamma irradiation. A comparative study
using some ion exchange resins revealed that the resins are either ineffective in nitrate medium or lack stability under irradiation.
In this paper are reported some experimental data related to the influence of preparation regimes and characteristics of exfoliated
graphite based sorbents produced by thermal expansion of H2SO4-graphite intercalation compounds (H2SO4-GICs) on their sorption properties. Investigations involving X-ray diffraction analyses, surface area, bulk density and oil
sorption capacity measurements, have been performed. Sorption capacity was discussed as a function of bulk density, total
pore volume and surface area. Some empirical correlation between studied characteristics of exfoliated graphite have been
found. The differences among the obtained samples, as a consequence of synthesis conditions, were also put in evidence by
thermal analysis (TG, DTG and DTA) performed after their exposure to oil sorption.
It was found that thermal analysis method could provide information about the exfoliated graphite pore system related to the
sorbed oil oxidation rate. The capacity for oil uptake was also discussed in the case of graphite oxide soot.
Authors:O. Štroffeková, V. Jánošová, M. Sýkorová, and E. Havránek
This paper aimed to the evaluation of different kinds of sorbent material preparation and to the evaluation of their characteristics
at different pH conditions by X-ray fluorescence analysis. This method is suitable for identification and determination of
elements in samples of different character, state and origin because it is a polycomponent, non-destructive, fast and simple
analytical method. Moreover, it allows time-advantageous and reliable measurements. This paper studies problems concerning
the determination of some selected elements (Mn, Fe, Ni, Cu, Zn, Pb) in pharmaceutical samples of sodium chloride in the solid
state as well as in its solution by sorption on chelating extraction membrane 3M Empore™ and on the strongly acidic ion-exchanger
Dowex 50Wx8. Conditions for the most effective sorption of determined elements are also interpreted.
The ability of the back-fill and the host rock materials to take up radioisotopes like 241Am, 85,89Sr and 137Cs has been examined as a function of contact time, pH, amount of sorbent, sorbate concentration, and the presence of complementary cations. A batch technique using actual borehole water from the granite formation has been utilized. In general, the uptake of nuclides by bentonite is much higher than that with granite. The sorption order of nuclides on bentonite is Am>Cs>Sr. The presence of complementary cations, Na+, K+, Ca2+ and Mg2+ depresses the sorption of Cs and Sr on bentonite. The sorption data have been interpreted in terms of Freundlich and Langmuir isotherm equations. Utilizing the Langmuir isotherm equation, the monolayer capacity, Vm,and the binding constant, K, have been evaluated. The change in free energy for the sorption of nuclides on bentonite has also been calculated.
An extraction chromatography method was developed for the separation of 239Np from 243Am in nitric acid solution. A sorbent based on aliphatic quaternary amine Aliquat-336 and hydrophobized silica gel was prepared. 239Np reduced to the oxidation state(IV) with ferrous sulfamate in 2M or 6M HNO3 sorbs on the prepared silica gel column. After washing with 0.1M ferrous sulfamate in 2.5M HNO3, 239Np is eluted with 0.1M HNO3 containing 0.02M HF. The separation of 243Am from 239Np is very effective. The purity of 239Np was found to be better than 99.5%. The proposed 239Np milking procedure is suitable for the preparation of 239Np tracer that can be used for the determination of 237Np radiochemical yield.
The removal of134Cs and60Co from radioactive process waste water using cetyl pyridinium chloride (CPC) as a collector and cobalt(II) hexacyanoferrate(II) as a precipitant for60Co and sorbent (ion exchanger) for134Cs was intensively investigated and the best removal conditions could be established. The results indicate that under the optimum conditions removals higher than 96% and 97% could be achieved for Co(II) and Cs(I), respectively. Cobalt(II) hexacyanoferrate(II) was found to have high affinity for cesium and can preferentially remove it in presence of relatively high amounts of other alkali or alkaline earth cations. A two-stage flotation process was successfully tested for the removal of both Cs(I) and Co(II) from waters containing both cations.
Authors:M. Hutta, S. Rippa, J. Kandráč, and M. Chalanyová
Post-column derivatization detection system based on dithizone solubilized in cetyltrimethyl-ammonium hydrogenesulfate micellar media at pH 2.0 was devised and evaluated for selective detection of mercury(II), methylmercury and phenylmercury in reversed-phase HPLC system with photometric detection at 500 nm. This reagent solution is fully compatible with acidic organo-aqueous mobile phases generally used in RPHPLC. With the aid of the detection systematic study of the retention behaviour of three mercury species on octadecylsilica sorbent was carried out. Influence of pH, acetonitrile volume fraction, complex forming additives was investigated in detail. In mobile phase consisting of 5–30% of acetonitrile in water at pH 2.0 and 2·10–4 mol·I–1 DCTA linear calibration curves were measured in range 20–1000 ppb with correlation coefficient better than 0.99. Detection limits were 1–5 ng for this three mercury species. Interferences of copper(II) and silver(I) are negligible.
CMPO/TBP sorbed on Amberlite XAD7 resin was used for the separation of actinides and lanthanides from nitric acid solutions
by extraction chromatography. The distribution ratios of actinides and lanthanide fission products (Ce, Eu) as a function
of acid concentration and some complexing agents were determined. In strong HNO3 medium (>1 mol/l) the tri-, tetra- and hexavalent actinides as well as the lanthanides have shown great affinity for the
CMPO/TBP/XAD7 sorbent. The same behavior was found in HCl medium except for trivalent actinides and lanthanides which show
lower distribution values in the same acid range. The effect of some complexing agents as DTPA and ammonium oxalate were also
investigated. In DTPA only hexavalent actinides showed higher distribution value. On the basis of these differences, an alternative
procedure for actinide-lanthanide separation and actinides from each other is proposed.
silylcellulosic derivatives with different substitution degree were examined as
sorbents for uranyl ions. The adsorption rate and capacity of cellulose and
modified cellulose were investigated in aqueous media, at various pH and
temperature values. The polymer - metal complexes of UO22+
were characterized by infrared and electronic spectra, and thermogravimetry.
The thermal behavior of cellulose (C), trimethylsilyl - cellulose (tmsc, SD=
2.85) and triphenylsilyl - cellulose (TPSC1, SD=2.89 and TPSC2, SD
=2.70) and their complexes with
uranyl ions in atmospheric air has been studied between room temperature and
600 °C. The Coats-Redfern method was applied to estimate the kinetic
parameters. The results revealed that the complexation of C and TMSC with UO22+
increases the thermal stability.