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Study of the immobilization of226Ra

I. Cement solidification of226Ra waste

Journal of Radioanalytical and Nuclear Chemistry
Authors:
R. Wang
,
X. Yang
, and
Q. Wu

Abstract  

A study of the immobilization for226Ra waste has been carried out. Cement-based concrete was used as a matrix for the solidification of radium waste. The experimental results show that the cement mixture with water/cement between 0.46–0.54 has higher strengh (above 20 MPa), and the compressive strength was not reduced by addition of 1% barite or the radium waste (RaSO4) into the concrete solid.

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Study of the immobilization of226Ra

II. Predictive model of radionuclide leaching behavior in a cement-based solid

Journal of Radioanalytical and Nuclear Chemistry
Authors:
X. Yang
,
W. Zhou
, and
R. Wang

Abstract  

A three-dimensional leaching model was developed to describe the leaching of radionuclide from a cement-based concrete solid. The film mass transfer and interparticle diffusion were considered simultaneously. On the basis of the derived model the long-term behavior of radium-226 leaching from the waste solid has been quantitatively investigated.

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Abstract  

A new method of thermal desorption chromatography, in which hydrogen is used as carrier instead of helium, and a water bath instead of an air bath, is presented for determining the specific surface area of uranium compounds. The method proposed has a higher accuracy and a better applicability.

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Abstract  

The kinetics of protein thermal transition is of a significant interest from the standpoint of medical treatment. The effect of sucrose (0–15 mass%) on bovine serum albumin denatured aggregation kinetics at high concentration was studied by the iso-conversional method and the master plots method using differential scanning calorimetry. The observed aggregation was irreversible and conformed to the simple order reaction. The denaturation temperature (T m), the kinetic triplets all increased as the sucrose concentration increased, which indicated the remarkable stabilization effect of sucrose. The study purpose is to provide new opportunities in exploring aggregation kinetics mechanisms in the presence of additive.

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Abstract  

The effect of glucose (0–15 mass%) on the kinetics of bovine serum albumin (BSA) denatured aggregation at high concentration in aqueous solution has been studied by differential scanning calorimetry. The observed denatured aggregation process was irreversible and could be characterized by a denaturation temperature (T m), apparent activation energy (E a), the approximate order of reaction, and pre-exponential factor (A). As the glucose concentration increased from 0 to 15 mass%, T m increased, E a also increased from 514.59409±6.61489 to 548.48611±7.81302 kJ mol−1, and A/s−1 increased from 1.24239E79 to 5.59975E83. The stabilization increased with an increasing concentration of glucose, which was attributed to its ability to alter protein denatured aggregation kinetics. The kinetic analysis was carried out using a composite procedure involving the iso-conversional method and the master plots method. The iso-conversional method indicated that denatured aggregation of BSA in the presence and absence of glucose should conform to single reaction model. The master plots method suggested that the simple order reaction model best describe the process. This study shows the combination of iso-conversional method and the master plots method can be used to quantitatively model the denatured aggregation mechanism of the BSA in the presence and absence of glucose.

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Abstract  

57Co was produced with high pure nature iron irradiated by 8.5MeV deuterons. TBP-benzene extraction method and anion-exchange method were used to separate and purify it. The purified57Co was prepared into standard solution of about 30 to 50 g Co2+/ml carrier concentration and about 0.1 mol/l HCl. The specific activity of the standard solution was measured with 4 (ppc)- coincidence counting method. The final result was 476.82(1±0.42%)Bq/mg.

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Summary

Rapid high-performance liquid chromatographic methods with evaporative light scattering detection (HPLC-ELSD) and electrospray ionization multistage mass spectrometry (HPLC-ESI-MSn) have been established and validated for simultaneous qualitative and quantitative analysis of eight steroidal saponins in ten batches of Gongxuening capsule (GXN), a widely commercially available traditional Chinese preparation. The optimum chromatographic conditions entailed use of a Kromasil C18 column with acetonitrile-water (30:70 to 62:38, υ/υ) as mobile phase at a flow rate of 1.0 mL min−1. The drift tube temperature of the ELSD was 102°C and the nebulizing gas flow rate was 2.8 L min−1. Separation was successfully achieved within 25 min. LC-ESI-MSn was used for unequivocal identification of the constituents of the samples by comparison with reference compounds. The assay was fully validated for precision, repeatability, accuracy, and stability, then successfully applied to quantification of the eight compounds in samples. The method could be effective for evaluation of the clinical safety and efficacy of GXN.

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Journal of Radioanalytical and Nuclear Chemistry
Authors:
S. Lahiri
,
X. Wu
,
Yang Weifan
,
Xu Yanbing
, and
Yuan Shuanggui

Abstract  

Liquid liquid extraction of 46Sc was studied with 1-phenyl-3-methyl-4-benzoyl-5-pyrazolone (PMBP). It has been found that PMBP extracts almost quantitatively scandium from 10-3 to 10-2M HCl solutions. Tributyl phosphate (TBP) has a pronounced antagonistic effect on the extraction process.

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Abstract  

The thermal decomposition of strontium acetate hemihydrate has been studied by TG-DTA/DSC and TG coupled with Fourier transform infrared spectroscopy (FTIR) under non-isothermal conditions in nitrogen gas from ambient temperature to 600°C. The TG-DTA/DSC experiments indicate the decomposition goes mainly through two steps: the dehydration and the subsequent decomposition of anhydrous strontium acetate into strontium carbonate. TG-FTIR analysis of the evolved products from the non-oxidative thermal degradation indicates mainly the release of water, acetone and carbon dioxide. The model-free isoconversional methods are employed to calculate the E a of both steps at different conversion α from 0.1 to 0.9 with increment of 0.05. The relative constant apparent E a values during dehydration (0.5<α<0.9) of strontium acetate hemihydrate and decomposition of anhydrous strontium acetate (0.5<α<0.9) suggest that the simplex reactions involved in the corresponding thermal events. The most probable kinetic models during dehydration and decomposition have been estimated by means of the master plots method.

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Abstract  

The exfoliated poly(vinyl chloride) (PVC)/montmorillonite (MMT) nanocomposites were synthesized by in situ intercalated polymerization of vinyl chloride (VC) in the presence of organic-intercalated montmorillonite (OMMT). Their structures and thermal properties were characterized. The results showed that layered silicates are well exfoliated and uniformly distributed in PVC matrix during in situ intercalated polymerization of VC in the presence of OMMT. The glass transition temperatures of PVC phases in the PVC/MMT nanocomposites are all lower than that of pristine PVC due to the incorporation of the exfoliated silicate layers in PVC matrix. The 5% mass loss temperature (T 5%), the dehydrochlorination temperature (T max1) of the PVC matrix decreased due to the free and interlayer water in MMT, the low thermal stability, and the enhanced dehydrochlorination of the PVC matrix by alkyl ammonium pre-treated MMT. However, the thermal decomposition temperature of the dehydrochlorinated PVC (T max2) and char at 600C are slightly increased in the presence of silicate layers.

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