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1.
S. C. Tripathi R. Kannan P. S. Dhami P. W. Naik S. K. Munshi P. K. Dey N. A. Salvi S. Chattopadhyay 《Journal of Radioanalytical and Nuclear Chemistry》2011,287(3):691-695
The improvement and the refinement of non-viable Rhizopus arrhizus biomass were investigated via immobilization. Immobilization was carried out by using sodium alginate/CaCl2 solution and formaldehyde/HCl cross-linking with dead Rhizopus arrhizus biomass and were used for the sorption of radionuclides from low level effluent wastes. The sodium alginate/CaCl2 immobilized biomass (ratio 1:2) showed about 86% sorption for 241Am activity but due to its soft nature and tendency to undergo distortion in shape, is unsuitable for practical applications.
The biomass cross-linked with 15% formaldehyde/0.1 M HCl solution has a relatively high mechanical strength and rigidity.
It was showing a sorption of >99% for 241Am activity and has the sorption capacity of ~65 mg/g for americium and uranium. Hence, it can be utilized for the removal
of radionuclides from radioactive waste effluents. 相似文献
2.
Retention of U(VI) by laumontite, a fracture-filling material of granite was investigated by conducting dynamic and batch
sorption experiments in a glove-box using a granite core with a natural fracture. The hydrodynamic properties of the granite
core were obtained from the elution curve of a non-sorbing tracer, Br−. The elution curve of U(VI) showed a similar behavior to Br−. This reveals that the retention of U(VI) by the fracture-filling material was not significant when migrating through the
fracture at a given condition. From the dynamic sorption experiment, the retardation factor R
a
and the distribution coefficient K
a
of U(VI) were obtained as about 2.9 and 0.16 cm, respectively. The distribution coefficient (K
d
) of U(VI) onto laumontite obtained by conducting a batch sorption experiment resulted in a small value of 2.3±0.5 mL/g. This
low K
d
value agreed with the result of the dynamic sorption experiment. For the distribution of uranium on the granite surface investigated
by an X-ray image mapping, the fracture region filled with laumontite showed a relatively lower content of uranium compared
to the surrounding granite surface. Thus, the low retention of U(VI) by the fracture-filling material can be explained by
following two mechanisms. One is that U(VI) exists as anionic uranyl hydroxides or uranyl carbonates at a given groundwater
condition and the other is the remarkably low sorption capacity of the laumontite for U(VI). 相似文献
3.
J. Kuwabara M. Yamamoto S. Oikawa K. Komura D. J. Assinder 《Journal of Radioanalytical and Nuclear Chemistry》1999,240(2):593-601
Long-lived radionuclides,99Tc,137Cs,237Np, Pu isotopes and241Am were determined in the long sediment cores collected from nine intertidal sites around the west Cumbria of the Irish Sea,
UK. The inventories of all nuclides measured varied considerably among the sampling sites, but generally their inventories
decreased with increasing distance from Sellafield. Furthermore, the inventory ratios with respect to relationship with distance
from Sellafield enabled comparison of transport behavior of99Tc,137Cs,237Np and241Am compared with239,240Pu. As a consequence, the apparent fractional rate of solution transport to the intertidal sediment was found to increase
as follows:99Tc>137Cs>237Np>239,240Pu≥241Am. 相似文献
4.
J. W. Mietelski P. Szwako E. Tomankiewicz P. Gaca S. Maek J. Barszcz S. Grabowska 《Journal of Radioanalytical and Nuclear Chemistry》2004,262(3):645-660
Results for 137Cs, 40K, 90Sr, 238,239+240Pu, 241Am and 243+244Cm measurements in plant, insects and forest litter samples collected at three sites in Poland are presented. New results are compared with some existing data for locations examined during previous studies. Insect samples were introduced now for the first time. Relatively high activities of 90Sr were noticed for spruce bark beetle (Ips typographus) and those for 137Cs, plutonium and 241Am for forest dung beetle (Anoplotrupes stercorosus). Faster than caused by physical decay decrease of radiocesium activity was noticed for the majority of plant and litter samples. The results for 239+240Pu for litter were similar to previous results, but the activities of 238Pu were smaller. The activity ratio between 241Am and 239+240Pu was found lower than expected for known proportions between global and Chernobyl fallout. Thus a kind of dynamic behavior of Pu and Am in the forest ecosystem is concluded. Transfer factors and aggregation coefficients were estimated and discussed for both plants and insects as well as between insects and the part of plants (or litter) they feed on. Many of them were never presented before.The authors are thankful to the Polish State Committee for Scientific Research for financial support of this investigation, Grant No. PG04 07520. 相似文献
5.
Sorption of Cs,Pu and Am on clay minerals 总被引:2,自引:0,他引:2
G. Lujanienė S. Motiejūnas J. Šapolaitė 《Journal of Radioanalytical and Nuclear Chemistry》2007,274(2):345-353
Performance assessment of radioactive waste disposal requires modeling of long-term migration of radionuclides through the
engineered barriers and the geological environment. The chemical complexity of sorption-desorption processes is usually reduced
to integrated parameter distribution coefficients (K
d
). There are a great number of publications on K
d
determination, however, the existing data on K
d
of radionuclides on different geological materials are for general understanding only and are not very useful for performance
assessment, since changes of the geological conditions result in variability of K
d
values by two orders of magnitude. In order to obtain realistic sorption data sets for safety relevant radionuclides present
in a cement/concrete based repository some preliminary studies were carried out. The development of sorption database for
the near-surface repository was started with measurements of cesium, plutonium and americium K
d
values. Several experiments were performed in order to determine the chemical composition of cement water which could originate
from infiltration of precipitation and from contact of groundwater with concrete. More than 100 batch sorption experiments
were conducted with two clay samples. Cs, Pu and Am K
d
values were determined for rainwater, groundwater and cement-water of different chemical compositions. Cs, Pu, Am K
d
values ranged from 450 to 9700, from 15000 to 21000 and 15000 to 80000 ml/g, respectively. Changes in the geochemical conditions
resulted in the variability of Cs, Pu and Am K
d
values. 相似文献
6.
《Journal of Radioanalytical and Nuclear Chemistry》2009,282(3):787-791
A sorption ability of titanium silicates (TiSi) and iron oxides towards Cs, Sr, Pu and Am was tested using the laboratory
batch method. The obtained results are expressed as distribution coefficients (Kd). TiSi synthesised using TiOSO4 revealed better sorption ability towards all studied radionuclides in comparison with TiSi produced on the basis of TiCl4. The Kd values ranged from 3.9 × 102 to 1.6 × 105 mL g−1 for Sr, from 6 to 4.1 × 104 mL g−1 for Cs, from 2.2 × 102 to 2.6 × 105 mL g−1 for Pu and from 50 to 1.6 × 104 mL g−1 for Am. The highest Pu Kd values (9 × 103–6.2 × 104 mL g−1) and better kinetics were found for iron oxides. 相似文献
7.
Release of long-lived radioactivity to the aquatic bodies from various nuclear fuel cycle related operations is of great environmental
concern in view of their possible migration into biosphere. This migration is significantly influenced by various factors
such as pH, complexing ions present in aquatic environment and sorption of species involving radionuclides on the sediments
around the water bodies. 241/243Am are two major radionuclides which can contribute a great deal to radioactivity for several thousand years. In the present
study, 241Am sorption on natural sediment collected from site near a nuclear installation in India, has been investigated under the
varying conditions of pH (3–10) and ionic strength [I = 0.01–1 M (NaClO4)]. The sorption of Am increased with pH of the aqueous medium [10% (pH 2) to ~100% (pH 10)], which was explained in terms
of the increased negative surface charge on the sediment particles. There was marginal variation in Am(III) sorption with
increased ionic strength (within error limits) of the aqueous medium suggesting inner-sphere complexation/sorption process.
Sediment was characterized for its elemental composition and structural phases using Energy Dispersive X-Ray (SEM-EDX) and
X-Ray Diffraction (XRD) techniques. Zeta-potential measurement at I = 0.1 M (NaClO4) suggested that Point of Zero Charge (pHPZC) was ~2, indicating the presence of silica as major component in the sediment. Kurabtov plot using sorption data as a function
of pH at fixed I = 0.1 M (NaClO4) indicated the presence of multiple Am(III) species present on the surface. Potentiometric titration of the suspension indicated
the presence of mineral oxide like behavior and assuming a generic nature (≡XOH) for all types of surface sites, protonation–deprotonation
constants and total number of sites have been obtained. The sorption data has been modeled using 2-pK Diffuse Double Layer
Surface Complexation Model (DDL-SCM). ≡XOAm2+ has been identified as the main species responsible for the sorption profile. 相似文献
8.
Sorption of radionuclides on homogenized soils (under 2.5 mm grain size) from synthetic groundwater of 8·10−3M ionic strength and pH 8.5 has been studied under dynamic (flow) and static (batch) conditions. The corresponding water-soluble
compounds, as carriers in the 10−6 mol/dm3 concentration, were added into the SGW prior to the experiments. Soil samples were taken from several locations around the
environment of the High Level Waste Storage Facility at Nuclear Research Institute Řež plc in 5–100 cm depth. The dynamic
experiments were carried out in columns made of PP+PE injection syringes of 17.8 cm length and 2.1 cm in diameter. A multi-head
peristaltic pump was used for pumping the water upward through the columns at a seepage velocity of about 0.06 cm/min in average.
The radioactive nuclides were added into the water stream individually in a form of a short pulse in 0.1 cm3 of demineralized water. Dynamic desorption experiments were performed with the same experimental arrangement using a mixture
of 10−2N H2SO4 and 10−2N HNO3 in a volume ratio of 2: 1. Retardation, distribution and hydrodynamic dispersion coefficients during transport of radionuclides
were determined by the evaluation of the integral form of a simple advection-dispersion equation, used for fitting experimental
data and modeling the theoretical sorption breakthrough and desorption displacement curves. The static experiments were realized
in 100 cm3 plastic bottles stirring 5 g of soil samples with SGW occasionally in a soil to SGW ratio of 1: 10 (m/V). Kinetic parameters including equilibrium sorption activity, activity transfer rate constants and sorption half-times were
also determined. The results of dynamic experiments were compared with static sorption experiments. 相似文献
9.
C. K. Kim S. Morita R. Seki Y. Takaku N. Ikeda D. J. Assinder 《Journal of Radioanalytical and Nuclear Chemistry》1992,156(1):201-213
Intertidal coastal and estuarine sediments from 24 sites in the Irish Sea have been analyzed for99Tc,237Np,238Pu,239,240Pu and241Am. The237Np activity and239Pu/240Pu ratio were measured simultaneously by ICP-MS, and99Tc was determined by HR-ICP-MS which is ten times more sensitive than Q-ICP-MS.The activities of99Tc,237Np,239,240Pu and241Am were distributed over a wide range of 1.5–70.5, 0.01–13.3, 2.3–1589, 2.6–1894 Bq/kg, respectively. Activities of these radionuclides decreased exponentially with distance from the Sellafield source. The241Am/239,240Pu and237Np/239,240Pu ratios were almost constant with distance from the Sellafield. This result suggests that the distribution and behavior of Np and Pu are controlled by complicated factors such as the influence of transport, the variation with time of Np/Pu ratio in the Sellafield discharges and sedimentary mixing processes in the Irish Sea. 相似文献
10.
D. K. Das P. N. Pathak S. Kumar V. K. Manchanda 《Journal of Radioanalytical and Nuclear Chemistry》2009,281(3):449-455
Sorption behavior of 241Am (~10−9 M) on naturally occurring mineral pyrite (particle size: ≤70 μm) has been studied under varying conditions of pH (2–11),
and ionic strength (0.01–1.0 M (NaClO4)). The effects of humic acid (2 mg/L), other complexing anions (1 × 10−4 M CO3
2−, SO4
2−, C2O4
2− and PO4
3−), di- and trivalent metal ions (1 × 10−3 M Mg2+, Ca2+ and Nd3+) on sorption behavior of Am3+ at a fixed ionic strength (I = 0.10 M (NaClO4)) have been studied. The sorption of 241Am on pyrite increased with pH from 2.8 (84%) to 8.1 (97%). The sorption of 241Am decreased with ionic strength at low pH values (2 ≤ pH ≤ 4), but was insensitive in the pH range of 4–10, suggesting the
formation of outer-sphere complexes on pyrite surface at lower pH, and inner-sphere complexes at higher pH values. The sorption
of 241Am increased in the presence of (i) humic acid (5 < pH < 7.5), and (ii) C2O4
2− (2 < pH < 3). By contrast, other complexing anions such as (carbonate, phosphate, and sulphate) showed negligible influence
on 241Am sorption. The presence of Mg2+, Ca2+ ions showed marginal effect on the sorption profile of 241Am; while the presence of Nd3+ ion suppressed its sorption significantly under the conditions of present study. The sorption of 241Am on pyrite decreased with increased temperature indicating an exothermic process. 相似文献
11.
N. N. Popova V. I. Zhilov S. V. Demin A. Yu. Tsivadze V. V. Yakshin O. M. Vilkova 《Russian Journal of Inorganic Chemistry》2011,56(7):1128-1132
Americium sorption by crown-ether-impregnated polymeric sorbents from nitric acid solutions and multicomponent nitrate solutions
that model process solutions was studied. Sorption of ballast elements by the unimpregnated Porolas-T support was studied.
The sorption coefficients K
d
of these elements on Porolas-T do not exceed 0.01. Sorption of the same elements by crown-ether-impregnated sorbents was
also studied. Dicyclohexano-18-crown-6 (DCH18C6) and its alkyl derivatives were used. Sorption coefficients were determined
for all ballast elements. At the final stage of the study, 241Am sorption coefficients of from multi-component solutions were determined. The data obtained signify the utility of crown-ether-impregnated
sorbents for recovering 241Am from multicomponent technological solutions. 相似文献
12.
The uptake behavior of long-lived radionuclides such as 134Cs (2.06 years), 137Cs (30 years) or 133Ba (10.54 years) on calcium alginate (CA) beads have been investigated. The CA beads are able to remove 133Ba (92%) at pH 7 after 90 min of exposure from the binary mixture of two. The separation method of short-lived daughter 137Ba (2.55 min) from its long-lived parent 137Cs (30 years) using this CA beads have also been developed. 相似文献
13.
Shuye Yang Xuebin Wang Haixun Guo Jian Liu Fenglong Wang Xianzhong Zhang 《Journal of Radioanalytical and Nuclear Chemistry》2008,278(1):165-171
Mixed ligand fac-tricarbonyl complex of [99mTc(CO)3-DMSA-MIBI] has been prepared starting from the precursor [99mTc(OH2)3(CO)3]+. The complex can be obtained in good yield and purity in a two-step procedure by first attaching meso-2,3-dimercaptosuccinic acid (DMSA, HOOCCH(SH)CH(SH)COOH) with [99mTc(OH2)3(CO)3]+, followed by addition of MIBI [tetrakis-2-methoxyisobutylisonitrile (CH3OC(CH3)2CH2-N≡C) copper(I) tetrafluoroborate] solution. The complex was characterized by TLC and HPLC and was studied by means of octanol-water
partition coefficient, electrophoresis, stability in vitro, and normal mice experiment. Biodistribution in mice demonstrated
that the complex showed higher myocardial uptake after 0.5-hour p.i. The ratios of heart/liver (%ID/g) in the case of 99mTc(CO)3-DMSA-MIBI was higher (1.88) than that observed in case of 99mTc-MIBI1 (0.93) after 0.5-hour p.i. (P<0.05). Results showed that the complex may be developed to a novel myocardial perfusion-imaging agent. 相似文献
14.
Emanuel Makrlík Petr Vaňura Jan Budka Pavel Selucky 《Monatshefte für Chemie / Chemical Monthly》2010,287(3):31-33
Abstract
From extraction experiments in the two-phase water–nitrobenzene system and γ-activity measurements, the stability constants of the tetraethyl p-tert-butyltetrathiacalix[4]arene tetraacetate (cone)·M+ complexes (M+ = Li+, H3O+, NH4 +, Ag+, or K+) were determined in water-saturated nitrobenzene. It was found that these constants increase in the cation order NH4 + < K+ < H3O+ < Ag+ < Li+ < Na+. 相似文献15.
Fan Caiyun Jia Hongmei Deuther-Conrad Winnie Brust Peter Steinbach J?rg Liu Boli 《中国科学B辑(英文版)》2006,49(2):169-176
A novel 99mTc labeled complex, [N-[2-((2-oxo-2-(4-(3-phenylpropyl)piperazin-1-yl)ethyl) (2-mercaptoethyl)amino)acetyl]-2-aminoethanethiolato]Technetium(V)
oxide (PPPE-MAMA’-99mTcO) ([
99m
Tc]-2) has been designed and prepared based on the integrated approach. The corresponding rhenium complex (PPPE-MAMA’-ReO)(Re-2) has been prepared and characterized. In vitro competition binding assays show moderate affinity of Re-2 towards σ1 and σ2 receptors with K
i values of 8.67 ± 0.07 and 5.71 ± 1.88 μmol, respectively. Planar images obtained at 0.5 h, 4 h, 20 h after i.v. injection
indicate the accumulation of [
99m
Tc]-2 in MCF-7 human breast tumor bearing mice at 20 h. Furthermore, the accumulation of [
99m
Tc]-2 has been inhibited at 20 h after co-injection of [
99m
Tc]-2 plus haloperidol (1 mg/kg). Biodistribution studies of [
99m
Tc]-2 display an in vivo tumor uptake of 0.14% ± 0.01% ID/g at 24 h post i.v. injection with a tumor/muscle ratio of 6.02 ± 0.87. The above results
suggest that [
99m
Tc]-2, derived from a previously published lead compound, retains certain tumor uptake and affinity for σ receptors. [
99m
Tc]-2 may be used as a basis for further structural modifications to develop tumor imaging agents with high affinity for σ receptors. 相似文献
16.
P. P. Povinec C. Badie A. Baeza 《Journal of Radioanalytical and Nuclear Chemistry》2002,251(3):369-374
A certified reference material (CRM) for radionuclides in seawater, IAEA-381 (Irish Sea Water), is described and the results of certification are presented. The material has been certified for nine radionuclides (40K, 90Sr, 137Cs, 237Np, 238Pu, 239Pu,240Pu, 239,240Pu and 241Am). Information on massic activities with the corresponding 95% confidence intervals are given for eight radionuclides (3H, 125Sb, 234U, 235U, 236U, 238U, 241Pu and 244Cm). Less reported radionuclides include 60Co, 99Tc, and 242Pu. The CRM may be used for quality assurance/quality control of the analysis of radionuclides in environmental water samples, for the development and validation of analytical methods and for training purposes. The material is available from the IAEA in 5 kg units. 相似文献
17.
E. Makrlík P. Selucky P. Vaňura P. Toman R. Rathore 《Journal of Radioanalytical and Nuclear Chemistry》2011,287(2):497-500
From extraction experiments and γ-activity measurements, the extraction constants corresponding to the general equilibrium M+(aq) + 1·Cs+(nb)
\rightleftarrows \rightleftarrows
1·M+(nb) + Cs+(aq) taking part in the two-phase water–nitrobenzene system (1 = hexaarylbenzene-based receptor; M+ = H3O+, NH4
+, Ag+, K+, Rb+, Tl+; aq = aqueous phase, nb = nitrobenzene phase) were evaluated. Furthermore, the stability constants of the ML+ complex species in nitrobenzene saturated with water were calculated; they were found to increase in the series of Rb+ < K+ < Ag+, Tl+ < H3O+, NH4
+. 相似文献
18.
The distribution coefficients Kd for the sorption of95mTc by peat as well as the corresponding rates of sorption and desorption were determined as a function of the concentration of the supporting electrolyte (CaCl2), the amount of dissolved oxygen and the pH of the solution. The results show that the Kd-values of Tc (added as Tc(VII)-pertechnetate) increase, if the concentration of CaCl2 or the amount of dissolved oxygen is decreased. The sorption was reversible with respect to the replacement of Tc by a CaCl2 solution. The half-times for the rates of sorption and desorption depend on the concentration of CaCl2 and dissolved oxygen and were in the range of 20–60 minutes and 500–900 minutes for the sorption and desorption processes, respectively. 相似文献
19.
Shabana Taj Din Muhammad M. Ashraf Chaudhry Muhammad Mazhar 《Journal of Radioanalytical and Nuclear Chemistry》2011,288(1):79-88
Potassium iron(III) hexacyanoferrate(II) supported on poly methyl methacrylate, has been developed and investigated for the
removal of lithium, rubidium and cesium ions. The material is capable of sorbing maximum quantities of these ions from 5.0,
2.5 and 4.5 M HNO3 solutions respectively. Sorption studies, conducted individually for each metal ion, under optimized conditions, demonstrated
that it was predominantly physisorption in the case of lithium ion while shifting to chemisorption with increasing ionic size.
Distribution coefficient (K
d) values followed the order Cs+ > Rb+ > Li+ at low concentrations of metal ions. Following these findings Cs+ can preferably be removed from 1.5 to 5 M HNO3 nuclear waste solutions. 相似文献
20.
Jinsheng Wang Rui Zuo Yanguo Teng Qinhong Hu Zongjian Sun 《Journal of Radioanalytical and Nuclear Chemistry》2010,283(2):319-328
Because of the deposit and accumulation from the debris flow, the heterogeneous geological characteristics is obvious for
a candidate very low level waste (VLLW) disposal site, with the grain size ranging from tens of microns to 75 cm. Therefore,
it is challenging to directly measure the sorption capacity of the media and the distribution coefficient of some radionuclides,
such as strontium. We have studies the correlation of the particle mass content with different grade size and the sorption
capacity, which is important in the modeling of radionuclide migration in the heterogeneous disposal site. A total of three
deep pits and five shallow trenches were excavated, and 21 solid samples were collected for laboratory experiments. The grade
and percentage of the different-sized particles were obtained, and the fractal dimension (D) of the media was calculated from the results of sieved experiments. Steady state sorption time and sorption isotherm of
strontium was determined in the heterogeneous media, and sorption and distribution of strontium in the heterogeneous media
were evaluated by the relationship between the mass percentage and distribution coefficient (K
d) of the fine-particle media, which was comprised of selected particles with a diameter less than 1 mm, and the correlation
on the K
d and D was regressed fit. The results indicated that fractal dimension bounded from 2.39 to 2.62 in the media, and K
d values of strontium ranged between 119 and 126 in the fine-particle media, and corresponding value was 11 and 43 in the original
media. The correlation between K
d and D was approximately linear. 相似文献