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1.
R. Druteikiené B. Lukšiené E. Holm 《Journal of Radioanalytical and Nuclear Chemistry》1999,242(3):731-737
A field experiment study was performed at the rural site of South-East Lithuania. The main tasks of the study included an
evaluation of the peculiarities of partition of239Pu in soluble (239Pu(NO3)4,239PuCl3) and insoluble (239PuO2) forms in soddy and forest soil horizons. The results of durable experiments (418 and 326 days) have shown that from 44.1%
to 92.2% of239Pu of investigated chemical forms were accumulated in the top (0–5 cm) soil layer. Some share (5.7–39.2%) of plutonium from
studied chemical forms was found in the 5–20 cm layers of studied soil samples (columns). Obtained distribution of plutonium
in soil layers may be attributed to the consideration that the migration rate to the soil depth for plutonium is 0.1–1.0 cm·y−1 but for some part of plutonium 10 times higher migration rate is characteristic as well. Plutonium transfer factor (TF) to
the grassland plants was calculated, the values ranged from 10−2 to 10−1. 相似文献
2.
Binding constants of lead by humic and fulvic acids studied by anodic stripping square wave voltammetry 总被引:1,自引:0,他引:1
A better understanding of metal ion binding to soil organic substances is of fundamental importance in geochemical modeling
of environments. Fulvic acids (FA) and humic acids (HA) make up an important part of soil organic matter, and their binding
capacity affects the fate of metal ions and plays an important role in their mobility. Binding constants of Pb(II) to HA and
FA were evaluated by anodic stripping square wave voltammetry (ASSWV) where the binding reaction was performed at pH 4.5 in
a medium of 0.020 mol l−1 KNO3. Results showed that ASSWV technique was well suited for the estimation of the binding capacity of a natural organic matter
towards heavy metals. Based on the voltammetric titration curves, binding constants of Pb(II) complexes formed with HA and
FA were 0.78 × 106 and 0.15 × 106 mol−1 l, which indicated that complex of Pb2+ with HA was more stable than with FA. The average molecular weight of HA and FA prepared from soil samples were also found
to be 1821 g mol−1 and 805 g mol−1, respectively. 相似文献
3.
Effect of pH,ionic strength and humic substances on the adsorption of Uranium (VI) onto Na-rectorite
Donglin Zhao Shubin Yang Shaohua Chen Zhiqiang Guo Xin Yang 《Journal of Radioanalytical and Nuclear Chemistry》2011,287(2):557-565
In this study, the adsorption of U(VI) from aqueous solution on Na-rectorite was studied as a function of various environmental
conditions such as contact time, pH, ionic strength, soil humic acid (HA)/fulvic acid (FA), solid contents, and temperature
under ambient conditions by using batch technique. The kinetic adsorption is fitted by the pseudo-second-order model very
well. The adsorption of U(VI) on Na-rectorite was strongly dependent on pH and ionic strength. A positive effect of HA/FA
on U(VI) adsorption was found at low pH, whereas a negative effect was observed at high pH. The presence of HA/FA enhanced
the U(VI) adsorption at low pH values, but reduced U(VI) adsorption at high pH. The thermodynamic parameters (ΔH
0, ΔS
0, and ΔG
0) were also calculated from the temperature dependent adsorption isotherms, and the results suggested that the adsorption
of U(VI) on Na-rectorite was a spontaneous and endothermic process. 相似文献
4.
Tatiana A. Zotina Galina S. Kalacheva Alexander Ya. Bolsunovsky 《Journal of Radioanalytical and Nuclear Chemistry》2011,290(2):447-451
Accumulation of americium (241Am) and plutonium (238,242Pu) and their distribution in cell compartments and biochemical components of the biomass of freshwater aquatic plants Elodea canadensis,
Ceratophyllum demersum and Myrioplyllum spicatum and aquatic moss Fontinalis antipyretica have been investigated in laboratory experiments. Americium and plutonium taken up from water by Elodea canadensis apical shoots were mainly absorbed by structural components of plant cells (90% for 241Am; 89% for 238Pu and 82–87% for 242Pu). About 10–18% of isotope activity was recorded in the cytosol fraction. The major concentration (76–92%) of americium
was bound to cell wall cellulose-like polysaccharides of Elodea canadensis, Myriophyllum spicatum, Ceratophyllum demersum and Fontinalis antipyretica, 8–24% of americium activity was registered in the fraction of proteins and carbohydrates, and just a minor concentration
(<1%) in the lipid fraction. The distribution of plutonium in the biomass fractions of Elodea was similar to that of americium. Hence, americium and plutonium had the highest affinity to cellulose-like polysaccharides
of cell walls of freshwater submerged macrophytes. 相似文献
5.
A. N. Dubey G. R. Relan S. Vaidyanathan 《Journal of Radioanalytical and Nuclear Chemistry》1999,240(3):741-746
A derivative spectrophotometric method has been developed for the simultaneous determination of uranium and plutonium at trace
levels in various process streams in 3M HNO3 medium using Arsenazo III. The method was developed with the objective of measuring both uranium and plutonium in the same
aliquot in fairly high burn-up fuels. The first derivative absorbances of the uranium and plutonium Arsenazo III complexes
at 632 nm and 606.5 nm, respectively, were used for their quantification. Mixed aliquots of uranium (20–28 μg/ml) and plutonium
(0.5–1.5 μg/ml) with U/Pu ratio varying from 25 to 40 were analysed using this technique. A relative error of about 5% was
obtained for uranium and plutonium. The method is simple, fast and does not require separation of uranium and plutonium. The
effect of presence of many fission products, corrosion products and complexing anions on determination of uranium and plutonium
was also studied. 相似文献
6.
Voltammetric Determination of Folic Acid with a Multi-Walled Carbon Nanotube-Modified Gold Electrode
The voltammetric behavior of folic acid (FA) at a multi-walled carbon nanotube (MWNT) modified gold electrode has been investigated
by cyclic voltammetry, chronoamperometry and chronocoulometry. The modified electrode exhibits a good promoting effect on
the electrochemical reaction of FA. FA can generate a well-defined anodic peak at around 0.83 V (vs. SCE) in 0.1 M H3PO4–NaH2PO4 buffer solution of pH 2.5. The peak results from a 2-electron transfer of FA, and the standard potential of FA is estimated
to be 0.79 V (vs. SCE). The parameters affecting the response of FA, such as solution pH, accumulation time, accumulation
potential, and amount of MWNTs are optimized for the determination of FA. Under the optimum conditions, the peak current changes
linearly with FA concentration in the range from 2.0 × 10−8 M to 1.0 × 10−6 M. This method has been applied to the determination of FA in drug tablets, and the recovery is 93.9–96.9%. In addition,
the influence of some coexistent species is examined. When a Nafion layer is introduced on the gold electrode before deposition
of MWNTs, the resulting composite electrode can give better response to FA. At the same time, the interference by some foreign
species is suppressed to some extent. 相似文献
7.
The profile distribution of arsenic(III) and arsenic(V) species in soil and groundwater was investigated in the samples collected
in 2005 from a hand-drilled well, in the Bozanta area, Baia Mare region, Romania. The total content of arsenic in the soil
was in the range of 525–672 mg kg−1 exceeding 21–27 times the action trigger level for sensitive soil. 0.9–11.3 % of the total content was soluble in water,
83.0–92.6 % in 10 mol dm−3 HCl and 2.6–13.3 % was the residual fraction. Arsenic(V) was the dominant arsenic species in the soil in the range of 405–580
mg kg−1. The distribution and mobility of arsenic species was governed by soil pH and contents of Al, Fe, and Mn. The mobility of
arsenic(V) decreased with depth, while that of arsenic(III) was high at the surface and in the proximity of groundwater. The
total concentration of arsenic in groundwater was (43.40 ± 1.70) μg dm−3, which exceeded the maximum contaminant level of 10 μg dm−3.
Presented at the 33rd International Conference of the Slovak Society of Chemical Engineering, Tatranské Matliare, 22–26 May
2006. 相似文献
8.
An ultra-performance liquid chromatography-tandem mass spectrometry method was developed, optimised and validated for the
quantification of synthetic folic acid (FA), also called pteroyl-l-glutamic acid or vitamin B9 and naturally occurring 5-methyltetrahydrofolate (5-MTHF) found in folate-fortified breads. Optimised
sample preparation prior to analysis involved addition of 13C5 labelled internal standards, treatments with α-amylase and rat serum, solid-phase extraction using aromatic-selective cartridges
and ultra-filtration. Analytes were separated on a Waters ACQUITY HSS T3 column during a 6-min run and analysed by positive
ion electrospray selected reaction monitoring MS/MS. Standard calibration curves for the two analytes were linear over the
range of 0.018–14 μg FA/g of fresh bread (r
2 = 0.997) and 9.3–900 ng 5-MTHF/g of fresh bread (r
2 = 0.999). The absolute recoveries were 90% and 76% for FA and 5-MTHF, respectively. Intra-day coefficients of variation were
3% for FA and 18% for 5-MTHF. The limit of detection was 9.0 ng/g for FA and 4.3 ng/g for 5-MTHF, determined using pre-extracted
tapioca starch as the blank matrix. The assay is rugged, fast, accurate and sensitive, applicable to a variety of food matrices
and is capable of the detection and quantification of the naturally occurring low levels of 5-MTHF in wheat breads. The findings
of this study revealed that the FA range in Australian fortified breads was 79–110 μg/100 g of fresh bread and suggest that
the flour may not have the mandated FA fortification level (200–300 μg/100 g of flour), though this cannot be determined conclusively
from experimental bread data alone, as variable baking losses have been documented by other authors. 相似文献
9.
Myung Ho Lee Euo Chang Jung Kyuseok Song Yun Hee Han Hyun Sang Shin 《Journal of Radioanalytical and Nuclear Chemistry》2011,287(2):639-645
This work investigates the sorption of americium [Am(III)] onto kaolinite and the influence of humic acid (HA) as a function
of pH (3–11). It has been studied by batch experiments (V/m = 250:1 mL/g, C
Am(III) = 1 × 10−5 mol/L, C
HA = 50 mg/L). Results showed that the Am(III) sorption onto the kaolinite in the absence of HA was typical, showing increases
with pH and a distinct adsorption edge at pH 3–5. However in the presence of HA, Am sorption to kaolinite was significantly
affected. HA was shown to enhance Am sorption in the acidic pH range (pH 3–4) due to the formation of additional binding sites
for Am coming from HA adsorbed onto kaolinite surface, but reduce Am sorption in the intermediate and high pH above 6 due
to the formation of aqueous Am-humate complexes. The results on the ternary interaction of kaolinite–Am–HA are compared with
those on the binary system of kaolinite–HA and kaolinite–Am and adsorption mechanism with pH are discussed. Effect of different
molecular weight of HA, with three HA fractions separated by ultrafiltration techniques, on the Am sorption to kaolinite were
also studied. The results showed that the enhancement of the sorption of Am onto kaolinite at the acidic pH conditions (pH
3–4) was higher with HA fractions of higher molecular weight. Also, the Am sorption over a pH range from 6 to 10 decreased
with decreasing molecular weight of HA. 相似文献
10.
S. A. Perevalov N. P. Molochnikova 《Journal of Radioanalytical and Nuclear Chemistry》2009,281(3):603-608
The sorption of Pu(IV), polymeric Pu(IV), Pu(V) and Pu(VI) from the 0.1 M NaClO4 solution onto multiwalled carbon nanotubes was investigated. The kinetic study of the sorption process have shown that the
polymeric Pu(IV) has the highest sorption rate, while decrease of sorption rate for plutonium aqua-ions in the order Pu(VI) > Pu(IV) > Pu(V)
was found. Strong dependence of sorption kinetics of ionic plutonium species on pH was shown, in contrast to polymeric species,
that were shown to quantitatively sorb (99%) in the wide pH range (pH 2–10). Two different sorption mechanisms for ionic and
polymeric plutonium species were proposed: on the bases of sorption isotherms chemisorptions of plutonium aqua-ions onto carbon
nanotubes and through intermolecular interaction for the polymeric plutonium species was defined. Distribution coefficients
of plutonium in various oxidation states were found to increase with pH, showing the highest values for polymeric plutonium
sorption (K
d
= 2.4 × 105 mL g−1 at pH = 6). 相似文献
11.
Tasoula Kiliari Ioannis Pashalidis 《Journal of Radioanalytical and Nuclear Chemistry》2010,284(3):547-551
The radioactivity concentration of 236Pu, 232U and 228Th in aqueous samples has been determined by means of alpha spectroscopy after chemical separation and pre-concentration of
the radionuclides by cation exchange and liquid–liquid extraction using the Chelex-100 resin and 30% TBP/dodecan, respectively.
Method calibration using a 236Pu standard solution containing the daughter radionuclides results in a detector efficiency of 18% and in a chemical recovery
for cation-exchange which is (30 ± 7)%, (90 ± 5)% and (20 ± 5)% for plutonium, uranium and thorium, respectively. The chemical
recovery for liquid–liquid extraction is found to be (60 ± 7)%, (50 ± 5)% and (70 ± 5)%, for plutonium, uranium and thorium,
respectively. The differences in the efficiencies can be ascribed to the oxidation states, the different actinides present
in solution. Taking into account that the electrodeposition of the radionuclides under study is quantitative, the total method
efficiency is calculated to be (18 ± 15)%, (46 ± 7)% and (15 ± 5)%, for plutonium, uranium and thorium, respectively, at the
mBq concentration range. The detection limit of the alpha spectrometric system has been found to be 0.2 mBq/L, suggesting
that the method could be successfully applied for the radiometric analysis of the studied radionuclides and particularly uranium
in aqueous samples. 相似文献
12.
K. K. Gupta S. K. Misra S. C. Tripathi Manmohan Kumar 《Journal of Radioanalytical and Nuclear Chemistry》2010,283(2):353-357
2-Ethylhexyl-2-ethylhexyl phosphonic acid (PC-88A) and Tributylphosphate (TBP) extractants have been attached to polypropylene
(PP) in granular, film and non-woven fabric forms, by a simultaneous γ-ray irradiation method. The extraction of plutonium
from the acidic radioactive liquid waste by modified polymers was studied by varying the γ-ray dose. The uptake of plutonium
was also studied by polyethylene (PE) in film form. This modified polymer also showed extraction capability for plutonium
from nitric acid medium. The uptake of plutonium depends upon the γ-ray dose as well as the nature and source of the polymer.
Liquid–solid extraction studies showed that the equivalent amount of uptake of plutonium on TBP–polyethylene film requires
twice the γ-ray dose as compare to TBP–polypropylene film. It was observed that at given γ-ray dose polypropylene fabric is
not sturdy, compare to the granules and films, and material leach out in aqueous phase. The presence of other solvents like
di-methyl formamide (DMF) and cyclohexane during γ-ray irradiation were able to enhance the extraction capabilities. The optimum
conditions established during this study was successfully applied for the separation of plutonium, uranium and thorium from
the fission products in acidic waste solution. 相似文献
13.
V. P. Korolev O. A. Antonova N. L. Smirnova A. V. Kustov 《Journal of Thermal Analysis and Calorimetry》2009,96(3):903-910
The heats of solution of tetrabutylammonium bromide have been measured in mixtures of formamide (FA) with methanol (MeOH)
and ethylene glycol (EG) at 313.15 K by calorimetric method. The standard enthalpies of solution in binary mixtures have been
extrapolated to infinite dilution by Redlich–Rosenfeld–Meyer type equation using the literary data at 298.15 K and the present
paper data at 313.15 K. The Debye–Hückel limiting law slope A
H required for calculation of the ∆sol
H
0 value has been obtained with application the new additive scheme of determination of the physic-chemical characteristics
of binaries. The scheme is tested on the example of Bu4NBr solutions in FA–MeOH mixture at 298.15 K. Its application yields the ∆sol
H
0 value very closed on the ones determined with the real (non-additive) characteristics of binaries. The standard enthalpies
of solution extrapolated by Redlich–Rosenfeld–Meyer type equation are in a good agreement with the ones computed in terms
of the Debye–Hückel theory in the second approximation. The heat capacities characteristics of Bu4NBr have been calculated in H2O–FA, MeOH–FA and EG–FA mixtures using the literary and present data. The sequence of solvents H2O > FA > EG > MeOH located on their ability to solvophobic solvation found by us earlier for enthalpic characteristics is
confirmed by the ∆C
p
0 values. The comparison of thermochemical characteristics of Bu4NBr solutions in aqueous and non-aqueous mixtures containing FA has been carried out. The own structure of water remains in
the region of small additions of formamide to co-solvents. It considerably differs the H2O–FA mixture from the investigated non-aqueous systems. 相似文献
14.
Madjid Hadioui Patrick Sharrock Mohamed-Oimar Mecherri Véronique Brumas Marina Fiallo 《Chemical Papers》2008,62(5):516-521
In the effort to improve the performance of hydroxylapatite (HA) in removing lead ions from aqueous solutions, millimeter-sized
granules with 50 % porosity were synthesized. Such HA particles, after drying at 100°C, or heating at 800°C or 1100°C, exhibited
the specific surface areas of 50 m2 g−1, 25 m2 g−1, and 5 m2 g−1, respectively. It was found that heavy metal sorption capacity of HAs can be related to their surface area. Non-calcined
granules were difficult to handle and easy to crush. Hardened granules showed heavy metal absorption on their outer surfaces.
Absorption capacity of sintered HA particles towards lead was lower but adsorbed lead ions were spread inside the porous structure
of HA granules more evenly. Under flow conditions, lead ions were captured by HA at a rate of 0.5 mg g−1 min−1. Small lead phosphate aggregates were released from the HA sorbent together with calcium ions. Size of the aggregates depended
on the lead concentration and ranged from 1–50 μm in diameter; the aggregates could be removed by ultrafiltration. Results
show that porous hardened HA granules can be used as an efficient phosphate source for the immobilization of lead ions from
aqueous media. Organic ligands tend to interfere with the water purification procedure. 相似文献
15.
Y. Q. Wang Q. H. Fan P. Li X. B. Zheng J. Z. Xu Y. R. Jin W. S. Wu 《Journal of Radioanalytical and Nuclear Chemistry》2011,287(1):231-237
The sorption of Eu(III) on calcareous soil as a function of pH, humic acid (HA), temperature and foreign ions was investigated
under ambient conditions. Eu(III) sorption on soil was strongly pH dependent in the observed pH range. The effect of ionic
strength was significant at pH < 7, and not obvious at pH > 8. The type of salt cation used had no visible influence on Eu(III)
uptake on soil, however at low pH values, the influence of anions was following the order: Cl− ≈ NO3
− > ClO4
−. In the presence of HA, the sorption edge obviously shifted about two pH units to the lower pH, whilst in range of pH 6–7,
the sorption of Eu(III) decreased with increasing pH because a considerable amount of Eu(III) was present as humate complexes
in aqueous phase, then increased again at pH > 11. The results indicated that the sorption of Eu(III) on soil mainly formed
outer-sphere complexes and/or ion exchange below pH ~7; whereas inner-sphere complexes and precipitation of Eu(OH)3(s) may play main role above pH ~8. 相似文献
16.
Both single stage and multi-stages experiments on stripping plutonium with N,N-dimethylhydroxylamine (DMHAN) as reductant with methylhydrozine (MMH) as supporting reductant were carried out. The effect
of contact time, temperature, acidity, concentration of DMHAN on back-extraction rate of plutonium was investigated in the
single stage experiment. The results demonstrated that the reaction of stripping Pu(IV) in the organic phase (30% TBP–kerosene)
1BF solutions by DMHAN exhibits excellent stripping efficiency. Under the given conditions, the back-extraction rate of plutonium
reaches 90% within 2 min. Higher temperature, lower acidity and the increased concentration of DMHAN benifit the stripping
reaction. The concentration profile of HNO3, uranium and plutonium were determined in a multi-stages mixer-settler after the steady state of the back-extraction, and
the multi-stages results show that the plutonium can be separated effectively from uranium. The recovery of plutonium and
uranium reach 99.995% or over 99.99% respectively. The separation factor of U from Pu (SFPu/U) is about 2 × 104. 相似文献
17.
V. C. Adya A. Sengupta B. A. Dhawale B. Rajeswari S. K. Thulasidas S. V. Godbole 《Journal of Radioanalytical and Nuclear Chemistry》2012,291(3):843-848
Trace metallic impurity analysis by spectroscopic techniques is one of the important steps of chemical quality control of
nuclear fuel materials. Depending on the burn-up and the storage time of the fuel, there is an accumulation of 241Am in plutonium based fuel materials due to β decay of 241Pu. In this paper, attempts were made to develop a method for separation of 241Am from 1.2 kg of analytical solid waste containing 70% U, 23% Pu, 5% Ag and 1–2% C as major constituents along with other
minor constituents generated during trace metal assay of plutonium based fuel samples by d. c. arc carrier distillation atomic
emission spectrometry. A combination of ion exchange, solvent extraction and precipitation methods were carried out to separate
~45 mg of 241Am as Am(NO3)3 from 15 L of the analytical waste solution. Dowex 1×4 ion exchange chromatographic method was used for separation of Pu whereas
30% TBP–kerosene was utilized for separation of U. Am was separated from other impurities by fluoride precipitation followed
by conversion to nitrate. The recovery of Pu from ion exchange chromatographic separation step was ~93% while the cumulative
recovery of Am after separation process was found to be ~90%. 相似文献
18.
Xuemei Ren Suowei Wang Shitong Yang Jiaxing Li 《Journal of Radioanalytical and Nuclear Chemistry》2010,283(1):253-259
The sorption of U(VI) from aqueous solution on MX-80 bentonite was studied as a function of contact time, pH, ionic strength,
solid contents, humic acid (HA), fulvic acid (FA) and temperature under ambient conditions using batch technique. The results
indicate that sorption of U(VI) on MX-80 bentonite is strongly dependent on pH and ionic strength. The removal of U(VI) to
MX-80 bentonite is rather quick and the kinetic sorption data is simulated well by a pseudo-second-order rate equation. The
presence of HA enhances the sorption of U(VI) on MX-80 bentonite obviously, but the influence of FA on U(VI) sorption is not
obvious. The thermodynamic parameters (ΔH
0, ΔS
0, and ΔG
0) for the sorption of U(VI) calculated from temperature dependent sorption suggest that the sorption reaction is endothermic
and spontaneous. 相似文献
19.
Ivana Cavoski Valeria D’Orazio Teodoro Miano 《Analytical and bioanalytical chemistry》2009,395(4):1145-1158
The aim of this work was to ascertain, on a comparative basis, the compositional, structural and functional differences occurring
between three humic acids (HAs), HA S1 (isolated from a Mediterranean brown soil), HA S2 (isolated from a Bavarian brown soil),
and HA SR (a Suwannee River standard aquatic HA, purchased from IHSS), and to investigate the influence of their intrinsic
properties on the types of binding mechanisms toward the pesticide rotenone. Original HAs and their corresponding HA–rotenone
products, obtained by two different interaction protocols, were analyzed for elemental and functional group composition, and
spectroscopic techniques, such as Fourier-transform infrared (FT IR) with Fourier self-deconvolution (FSD) and fluorescence
both in the single-scan and in three-dimensional modes. The HA S1 sample appeared to be characterized by a greater aromaticity
degree and lower polarity with respect to the HA S2, featured by a mixed aromatic/aliphatic character, whereas mainly aliphatic
and acidic resulted the HA SR. The data obtained suggested that the low water-soluble, non-polar pesticide rotenone resulted
preferentially adsorbed onto HAs by hydrophobic interaction, that was the prevailing mechanism in the order HA S1 > HA S2 >>> HA
SR, whereas hydrogen bonds resulted predominant in the opposite order. 相似文献
20.
Songsheng Lu Zhiqiang Guo Caicai Zhang Shouwei Zhang 《Journal of Radioanalytical and Nuclear Chemistry》2011,287(2):621-628
MX-80 bentonite was characterized by XRD and FTIR in detail. The sorption of Th(IV) on MX-80 bentonite was studied as a function
of pH and ionic strength in the presence and absence of humic acid/fulvic acid. The results indicate that the sorption of
Th(IV) on MX-80 bentonite increases from 0 to 95% at pH range of 0–4, and then maintains high level with increasing pH values.
The sorption of Th(IV) on bentonite decreases with increasing ionic strength. The diffusion layer model (DLM) is applied to
simulate the sorption of Th(IV) with the aid of FITEQL 3.1 mode. The species of Th(IV) adsorbed on bare MX-80 bentonite are
consisted of “strong” species
o \textYOHTh4 + \equiv {\text{YOHTh}}^{4 + } at low pH and “weak” species
o \textXOTh(OH)3 \equiv {\text{XOTh(OH)}}_{3} at pH > 4. On HA bound MX-80 bentonite, the species of Th(IV) adsorbed on HA-bentonite hybrids are mainly consisted of
o \textYOThL3 \equiv {\text{YOThL}}_{3} and
o \textXOThL1 \equiv {\text{XOThL}}_{1} at pH < 4, and
o \textXOTh(OH)3 \equiv {\text{XOTh(OH)}}_{3} at pH > 4. Similar species of Th(IV) adsorbed on FA bound MX-80 bentonite are observed as on FA bound MX-80 bentonite. The
sorption isotherm is simulated by Langmuir, Freundlich and Dubinin–Radushkevich (D–R) models, respectively. The sorption mechanism
of Th(IV) on MX-80 bentonite is discussed in detail. 相似文献