共查询到20条相似文献,搜索用时 500 毫秒
1.
H. J. Ding Y. N. Niu Y. B. Xu W. F. Yang S. G. Yuan Z. Qin X. H. Zhou 《Journal of Radioanalytical and Nuclear Chemistry》2006,268(2):433-436
Summary The
extraction of protactinium with Aliquat 336 (methyl-tri-caprylyl ammonium
chloride) in toluene, cyclohexane and chloroform from HCl, HNO3, H2SO4,
HClO4, HF and mixed HCl-HF media was investigated by radioactive
tracer technique. Distribution ratios of protactinium between the aqueous
solution and the organic phase were determined as a function of shaking time,
concentrations of acid in aqueous solution phase, extractant concentration and
type of diluents in the organic phase. Aliquat 336 can almost quantitatively
extract protactinium from strong HCl solution. At the same time, small amounts
of HF in HCl solutions have a strong effect on Pa distribution.</p>
</p> 相似文献
2.
Summary Macroporous
methyl methacrylate polymeric resin (XAD-7) was investigated incorporating both
acidic organophosphorous extractant (cyanex-301) and one neutral extractant
from the followings: dibenzo 18 crown 6 (DB18C6), 18 crown 6 (18C6) and 15
crown 5 (15C5). The sorption behavior of the solvent impregnated resin (SIR)
towards thorium ion, including batch equilibrium, and kinetic operation are
described. Different factors affecting the uptake of metal ions and hence, the
separation efficiency of the impregnated resins were investigated. The maximum
uptakes of Th4+ were found to be 62.9, 66.7 and 92.6% for DB18C6,
18C6 and 15C5, respectively. Synergistic extraction of various CE towards
thorium ion was tested with cyanex-301 to enhance the sorption capacity as well
as the selective separation efficiency. A relatively high capacity of the
chelating resin towards tetravalent thorium was found. The capacities of the
co-impregnated resins were found to be 2.11, 2.42 and 3.85 mmol/g for DB18C6,
18C6 and 15C5, respectively. The impregnated resin containing cyanex-301 and
15C5 can be utilized for selective separation and pre-concentration of thorium
ion from nitrate medium in the presence of several interfering metal ions.</p>
</p> 相似文献
3.
P. Mell J. Megyeri L. Riess Z. Máthé J. Csicsák K. Lázár 《Journal of Radioanalytical and Nuclear Chemistry》2006,268(2):405-410
Summary Sorption of60Co,85Sr, 137Cs and125I have been studied on samples
originated from Boda (siltstone-) claystone formation (BCF) (Hungary). The
distribution of Kdvalues have been determined in static batch
experiments using natural groundwater. The order of sorption of isotopes was
Co>Cs>Sr>I, where iodine exhibits sorption properties in a modest
extent. The sorption isotherm was determined for Cs from measurements carried
out in 10-5-10-1M initial concentration range. The
isotherm can be described with non-linear Freundlich approximation in the range
of</o:p></p>
10-7-10-4M equilibrium concentration. At
concentrations >10-2M the isotherm achieves saturation. Hence, it is suggested that sorption
of Cs on BCF is dominated by cation-exchange reactions on the illite mineral
component. In the case of Co and Sr, precipitation reactions occurred during
the experiments performed with carrier-containing solutions. This can be
attributed to the low values of solubility product constants of SrCO3, SrSO4and Co(OH)2, formed from anions present in the
natural groundwater.</p>
</p> 相似文献
4.
A. Bhattacharyya P. K. Mohapatra P. N. Pathak V. K. Manchanda 《Journal of Radioanalytical and Nuclear Chemistry》2006,268(2):323-328
Summary Sorption
behavior of Th and U on cation-exchange resins was investigated from nitric
acid medium by both batch and column methods. The cation-exchange studies
involved the sorption of UO22+ and Th4+ and
their cationic complexes onto Dowex 50Wx8 and Dowex 50Wx4 resins (50-100 mesh).
The batch data yielded a separation factor (Kd,Th/Kd,U)
value of >100 for the cation-exchanger, Dowex 50Wx4 at 1-2M HNO3.
Separation of uranium from thorium was also carried out by column method in
nitric acid medium using cation-exchangers, Dowex 50Wx4 as well as Dowex 50Wx8.
While uranium elution was possible at 1M HNO3, Th could be eluted
only at higher concentration of nitric acid (>6M). The stripped solution
emanating from a mixer settler employing di-2-ethyl hexyl isobutyramide as
extractant and feed solution similar to THOREX process comprising 350 mg/l U
and 380 mg/l Th in 0.75M HNO3 was loaded on the column and the
decontamination factor value for U in the product was >1000.</p>
</p> 相似文献
5.
Adel M. El-Menshawy M. E. Khalifa 《Journal of Radioanalytical and Nuclear Chemistry》2006,268(2):341-348
Summary Duolite
C20 resin modified with trimethylammonium acetosalycoylhydrazone has been
developed, for the selective separation and/or preconcentration of uranium. The
modified resin was characterized by elemental analysis and infrared spectra.
Batch and column modes were applied. The newly designed resin quantitatively
sorbs uranium ion at pH 3 when the flow rate equals to 2 ml . min
-1 . The sorption capacity was 0.750 mmol . g-1 for
uranium ion, whereas its preconcentration factor was 200. The lower limit of
detection was 5 ng . ml-1 and its desorption was
effective with 5 ml of 3 mol . l-1 HCl or HNO3
prior to detection spectrophotometry. The modified resin was highly
ion-selective in nature even in the presence of large concentrations of
electrolyte or organic media, with a preconcentrating ability for uranium ion.
The modified resin was tested on its utility with synthetic, real and certified
ore samples, showed RSD values of <2% reflecting the accuracy and
reproducibility of the newly modified resin.</p>
</p> 相似文献
6.
M. W. Abdel Raouf K. Farah M. Nofal A. Alian 《Journal of Radioanalytical and Nuclear Chemistry》1997,221(1-2):153-159
Sorption of124Sb(III) from benzene, toluene, o-xylene and nitrobenzene on treated fly ash, pyrolysis residue and bentonite clay was studied at room temperature using the batch method. In comparison to a former study for the sorption of124Sb(V), the results revealed relatively higher sorption of the trivalent state than the pentavalent one. According to the type of the nonpolar solvent used, the order of uptake of the radioactive isotopes was often o-xylenetoluene>benzene. The sorption tendency of the sorbents used towards the radionuclides was: bentonitepyrolysis residue>treated fly ash. Sorption from an aqueous medium on the same sorbents has also been investigated for124Sb(III) compared to124Sb(V),152Eu(III) and their mixtures. The obtained results showed that the order of uptake of the different radionuclides was: Eu(III)>>Sb(III)>Sb(V)>mixture. The investigation was extended to the desorption studies of these radionuclides in the acidic and the neutral media from the dried radioactivity loaded sorbents. 相似文献
7.
Shuddhodan P. Mishra Diwakar Tiwari Shailesh Kumar Prasad R. S. Dubey Manisha Mishra 《Journal of Radioanalytical and Nuclear Chemistry》2006,268(2):191-199
Summary The
uptake of indigenously synthesized amorphous stannic and zirconium phosphate
was assessed for, one of the important fission fragment, cesium from aqueous
solutions using a radiotracer technique. A virtual increase in sorptive
concentration (from 1.0 . 10-8 to 1.0 . 10-2
mol . dm-3) and pH (from 2.4 to 10.2) and temperature
(from 303 to 333 K) enhanced the uptake of cesium on stannic phosphate.
However, the extremely high degree of uptake of cesium on zirconium phosphate
was almost unaffected with the dilution beyond 10-5 mol .
dm-3 and pH (i.e., from 2.4 to 10.2) and temperature (from 303 to
323 K). Irreversible uptake occurring for these solids follow the Freundlich
adsorption isotherm and the presence of several complexing agents viz.,
sulphate, phosphate, glycine and EDTA did not affect appreciably the uptake of
cesium on zirconium phosphate but it did affect for stannic phosphate system.
Both these solids showed good radiation stability towards a 11.1 GBq Ra-Be
neutron source having neutron flux ca. 3.2 . 106 n .
cm-2 . s-1 and associated with a nominalg-dose of ca.
1.72 Gy/h, at least for the uptake of cesium.</p>
</p> 相似文献
8.
H. Kazemian H. Zakeri M. S. Rabbani 《Journal of Radioanalytical and Nuclear Chemistry》2006,268(2):231-236
Summary Potassium
nickel hexacyanoferrate, KNiFC, was incorporated in the porous matrix of
zeolites by successive impregnation with Ni(NO3)2 and</o:p></p>
K4Fe
(CN)6.1 CFC and PFC exchangers were first prepared by
impregnating the potassium nickel hexacyanoferrate into the clinoptilolite and
the synthetic P zeolite, respectively. Ion-exchange isotherms and breakthrough
curves were plotted. Results showed that the CFC sorbent is suitable for
removal of Cs+ where PFC is more suitable for Sr2+.
Negative effect of Na+ as a competing ion in these exchangers was
less than in the parent zeolites. Isotherm plots fitted the Langmuir equation.</p>
</p> 相似文献
9.
Sh. Yu X. Li A. Ren D. Shao Ch. Chen X. Wang 《Journal of Radioanalytical and Nuclear Chemistry》2006,268(2):387-392
Summary The
removal of heavy metal ion Co(II) from aqueous solution was studied usingg-Al2O3
by batch technique. The experiments were performed at T=20±2 °C, in 0.01M
NaNO3 solutions and under aerobic conditions. The effect of pH,
ionic strength, fulvic acid (FA) and alumina amount on the sorption of Co(II)
on alumina were also investigated. The pH affected the sorption of Co(II)
significantly as compared with the effect of FA and ionic strength. The results
indicated that strong chemical bonds are formed between Co(II) and functional
groups of the bare or FA coated alumina, and a precipitation of Co(II) takes
place on the alumina surface, induced by a transition from the adsorption to
surface. The addition sequences of Co/FA on Co(II) sorption were also studied:
the sorption of Co(II) in the ternary system was found independent of addition
sequences.</p>
</p> 相似文献
10.
Pratibha Sharma Renu Tomar Pankaj Sharma Radha Tomar 《Journal of Radioanalytical and Nuclear Chemistry》2006,268(2):329-336
Summary Sorption
and desorption of UO22+, Th4+ and Ru3+
on the synthetic analogue of the mica mineral muscovite has been studied by a
batch technique. The synthesized gel was characterized by XRD, EDXRFS, FTIR,
TGA and SEM and was found to have a composition K1.4Al4.2(Si6Al2O20)(OH)4
. 2H2O. Different parameters like acid concentration, contact
time, amount of gel, composition of gel: OPC admixture, effect of temperature,
desorption of metal ions from loaded muscovite and effect on crystal morphology
due to loading of metal ions were studied. The results has been expressed in
terms of distribution coefficient (Kd).</p>
</p> 相似文献
11.
D. Nayak M. Nag S. Banerjee R. Pal S. Laskar S. Lahiri 《Journal of Radioanalytical and Nuclear Chemistry》2006,268(2):337-340
Summary The
bioaccumulation of 198Au radionuclide, by Rhizoclonium riparium
a member of Chlorophyceae has been studied. It has been observed that
accumulation of gold on Rhizoclonium is almost pH independent and
slightly higher at basic pH. Accumulation of gold was studied with 198Au
radiotracer, 0.1, 1 and 5 ppm concentrations of gold. It has been concluded
from the biochemical analysis that the gold accumulation is due to adsorption
in the cellulose and not in protein, fat and carbohydrate. Accumulated gold was
recovered when washed with conc. HNO3.</p>
</p> 相似文献
12.
Chien C. Lin C. F. Wang Y.C. Sun J. H. Chao C. L. Tseng 《Journal of Radioanalytical and Nuclear Chemistry》2006,268(2):419-424
Summary Exploratory
experiments have been carried out to investigate the effects of gamma-radiation
on iodine aerosols under various chemical conditions. The results indicate that
iodide ions (I-) in aerosol can be readily oxidized to I2
and HIO, and some iodide ions may be converted to organic iodine when organic
additives are present in the KI solution from which the aerosol is generated.
The results also suggest that the chemical transformation of irradiated iodine
aerosol depends on the chemical environment both carrier gas and iodide
solution.</p>
</p> 相似文献
13.
K. Dasthaiah B. Robert Selvan A. S. Suneesh K. A. Venkatesan M. P. Antony R. L. Gardas 《Journal of Radioanalytical and Nuclear Chemistry》2017,313(3):515-521
The imidazolium bis(2-ethylhexyl) phosphate moiety was chemically attached on silica gel by chemical modification. The resulting product ([SG-Im]+ [DEHP]?) was characterized by FT-IR spectroscopy, thermogravimetry and elemental analysis. The sorption behavior of Am(III) and Eu(III) on [SG-Im]+ [DEHP]? was studied from dilute nitric acid medium for the separation of Am(III) and Eu(III) from aqueous waste. The effect of time, concentrations of nitric acid and europium in aqueous phase on the distribution coefficient (K d) was studied. The study indicated the possibility of using modified silica for the separation of Eu(III) from Am(III) with high separation factors (>50 at 0.1 M HNO3). 相似文献
14.
P. Mell J. Megyeri L. Riess Z. Máthé G. Hámos K. Lázár 《Journal of Radioanalytical and Nuclear Chemistry》2006,268(2):411-417
Summary Diffusions of85Sr,137Cs,60Co and125I radionuclides have been studied in
borecore samples from Boda siltstone/claystone formation (BCF) under ambient
and in situ conditions. In-diffusion (85Sr,137Cs,60Co and125I) and through-diffusion measurements (125I) were performed at ambient
conditions, and for iodine, in-diffusion measurements were also carried out at
in situ conditions (100 bar, 50 °C). In the case of cationic species
carrier-containing solutions were also applied.60Co was detected only in the first
slice of borecore at each sample, while137Cs was detected also in the first-, second- and
third slices according to the concentration-increase of inactive carrier. Among
the investigated cations,85Sr exhibited the fastest diffusion rate with
2.7-6.0 . 10-12m2/s
apparent diffusivity values. In the course of in-diffusion measurements 4.7
. 10-11
m 2 /s, during through-diffusion investigations 1.4-1.6 .
10-12m2/s and at in situ conditions 5.0-8.0
. 10-12
m2/s
apparent diffusivities were obtained for125I.Modest sorption of125I can also be deduced from the
results.</p>
</p> 相似文献
15.
Simultaneous
measurement of gamma-rays and neutron fluences</p>
using
a HPGE detector</o:p></p>
</p>
Z. B. Alfassi T. Zlatin U. German 《Journal of Radioanalytical and Nuclear Chemistry》2006,268(2):237-241
Summary A
simultaneous determination of gamma and neutron fluences in a mixed neutron +
gamma field can be achieved by gamma-ray spectrometry, optimizing the
moderator-converter-detector assembly and measuring both the direct gamma-lines
and the neutron induced prompt gammas. For the prompt gamma-lines a combination
of high efficiency and low background is the goal, and it can be best achieved
if the gamma-energy is in the range above about 1 MeV up to 2.5 MeV. The
optimal moderator-converter thickness can be determined experimentally. Most
converter elements produce gamma-rays in the low energy range. If chlorine is
used as a converter, the 1164.7 keV peak and the 1950-1960 keV peaks seems to
be a good choice. A very practical material containing chlorine is PVC. It is
an efficient moderator, it is solid, common, and can be handled easily.</p>
</p> 相似文献
16.
A. Alian F. H. El-Sweify N. Zakaria M. Nofal 《Journal of Radioanalytical and Nuclear Chemistry》1996,209(1):135-145
The extraction of Sb(III) chloride by nonpolar solvents from 0.15M HCl was studied as a function of sulphuric acid concentrations in the aqueous phase. The distribution of Sb(III) chloride between the nonpolar solvents benzene, toluene, xylene, nitrobenzene, cyclohexane, chloroform and carbon tetrachloride and filter paper is reported. In case of benzene the Sb(III) activity (given in counts·s–1·ml–1) decreases from 1500 to 200 after 24 hours. The corresponding values are about 1200 and 540 for toluene, 1330 and 50 for xylene, 1050 and 700 for nitrobezene, 1080 and 22 for cyclohexane, 330 and 30 for chloroform and 130 and 40 for carbon tetrachloride. More than 95% of the adsorbed Sb(III) is desorbed by 1M HNO3, 1M HCl or 0.5M H2SO4 by contacting the loaded filter paper with any of these acids for 27 hours. 相似文献
17.
A. Abbady 《Journal of Radioanalytical and Nuclear Chemistry》2006,268(2):243-246
Summary Samples
of limestone, sand, marble, clay brick, red brick, gypsum, Portland cement and
white cement collected from upper Egypt used in building manufacturing have
been analyzed for the natural radionuclides 226Ra, 232Th and 40K usingg-ray
spectrometry. The specific concentrations for 226Ra, 232Th and 40K, ranged from 20-88,
13-115 and 54-304 Bq/kg, respectively. The average specific activities of these
radionuclides were compared. Higher values of 226Ra and 232Th could be noticed in marble while that of 40K
was in red bricks. Radium equivalent activities, dose rate and the annual
gonadal dose equivalents AGDE were calculated for the measured samples to
assess the radiation hazard arising from using those materials in the
construction of dwellings. The radioactive heat production values of the
selected materials have also been determined. They vary from a minimum of 0.41
for white cement to a maximum of 5.52mW/m3 for
marble samples. The calculated heat-production values are quite similar to
those estimated in Corsica.</p>
</p> 相似文献
18.
This paper reports silica gel loaded with p-tert-butylcalix[8]arene as a new solid phase extractor for determination of trace level of uranium. Effective extraction conditions
were optimized in column methods prior to determination by spectrophotometry using arsenazo(III). The results showed that
U(VI) ions can be sorbed at pH 6 in a mini-column and quantitative recovery of U(VI) (>95–98%) was achieved by stripping 0.4 mol L−1 HCl. The sorption capacity of the functionalized sorbent is 0.072 mmol uranium(VI) g−1 modified silica gel. The relative standard deviation and detection limit were 1.2% (n = 10) for 1 μg uranium(VI) mL−1 solution and 0.038 μg L−1, respectively. The method was employed to the preconcentration of U(VI) ions from spiked ground water samples. 相似文献
19.
D. Bontea C. Mita D. Humelnicu 《Journal of Radioanalytical and Nuclear Chemistry》2006,268(2):305-311
Summary Three
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.</p>
</p> 相似文献
20.
Summary A
rapid separation of microamounts of Sr2+ from Y3+ using
HCl, 15-crown-5 (15C5) and hydrogen dicarbollylcobaltate (H+B-)
in the two-phase water - nitrobenzene extraction system was developed. The
reached separation factor a(Sr/Y) was approximately 10. 5.4</p>
__</p> 相似文献