Dissolution Behavior of Lead Borate Glass under Simulated Geological Disposal Conditions

MRS Advances ◽  
2018 ◽  
Vol 3 (21) ◽  
pp. 1139-1145
Author(s):  
Atsushi MUKUNOKI ◽  
Takahiro KIKUCHI ◽  
Tamotsu CHIBA ◽  
Tomofumi SAKURAGI ◽  
Toshihiro KOGURE ◽  
...  
Keyword(s):  
Borate Glass ◽  
Chemical Species ◽  
Xrd Analysis ◽  
Underground Water ◽  
Dissolution Behavior ◽  
Lead Borate ◽  
Geological Disposal ◽  
Glass Dissolution ◽  
Constituent Phase

ABSTRACTDevelopment of an iodine immobilization technique that can fix radioactive iodine in waste form for a long period and constrain its leaching into pore water is necessary in order to secure the long-term safety of geological disposal of transuranic (TRU) waste.Lead borate glass vitrified at a low temperature is regarded as one of the promising immobilization materials of Iodine-129 which will be removed from spent AgI filters generated from reprocessing plants and may have a significant effect on long term safety of geological disposal.Leaching experiments in bentonite-equilibrium water have been conducted to understand the lead borate glass dissolution behaviors in possible geological disposal conditions. Boron dissolved with the highest rate in all types of the solutions and was regarded as an index element to represent the glass dissolution rate. On the other hand, lead dissolved with a far slower rate. The chemical species and possible precipitating minerals of lead were examined by a geochemical calculation code for typical underground water. Altered glass surfaces were investigated by SEM, TEM and XRD. XRD analysis showed that the main constituent phase of the altered layer was hydrocerussite, Pb3(CO3)2(OH)2, that was predicted by the geochemical simulation as well.

Corrosion and Alteration of Lead Borate Glass in Bentonite Equilibrated Water

2013 ◽  
Vol 1518 ◽  
pp. 15-20 ◽  
Author(s):  
Atsushi MUKUNOKI ◽  
Tamotsu CHIBA ◽  
Takahiro KIKUCHI ◽  
Tomofumi SAKURAGI ◽  
Hitoshi OWADA ◽  
...  
Keyword(s):  
Borate Glass ◽  
Experimental System ◽  
Xrd Analysis ◽  
Dissolution Behavior ◽  
Lead Borate ◽  
Geological Disposal ◽  
Glass Dissolution ◽  
Altered Layer ◽  
Glass Surfaces

ABSTRACTThe development of an iodine immobilization technique that can fix radioactive iodine in waste form for a long period and constrain its leaching into pore water is necessary in order to secure the long-term safety of geological disposal of transuranic (TRU) waste. Lead borate glass vitrified at a low temperature is regarded as a promising material for immobilizing the Iodine-129 that is recovered from spent AgI filters generated by reprocessing plants in Japan and which may have a significant effect on the long-term safety of geological disposal.Batch leaching tests were conducted to understand glass dissolution behavior in various solutions that account for geological disposal conditions. Boron dissolved at the highest rate in all types of solutions to be used as an index element for measuring the glass dissolution rate. On the other hand, lead dissolved in these solutions at a much lower rate. These results are consistent with an electron micro-probe analysis (EPMA) of the altered glass surfaces that indicated the depletion of boron and enrichment of lead near the surfaces.The altered glass surfaces were further examined by scanning and transmission electron microscopy (SEM/TEM) and X-ray diffraction (XRD). SEM/TEM observation showed formation of a porous altered layer consisting of fine crystallites on the pristine glass and euhedral crystals on the altered layer. XRD analysis indicated that the fine crystallites and euhedral crystals are hydrocerussite, Pb3 (CO3)2(OH) 2, which was predicted by geochemical calculation as the precipitate for the experimental system.

Fitting Element Profiles for Predicting Glass Dissolution Rates in Synthetic Interstitial Clay Water

2002 ◽  
Vol 757 ◽  
Author(s):  
Marc Aertsens ◽  
Karel Lemmens ◽  
Pierre Van Iseghem
Keyword(s):  
Diffusion Layer ◽  
Diffusion Coefficients ◽  
Water Flux ◽  
Dissolution Behavior ◽  
Matrix Elements ◽  
Hydrogen Water ◽  
Glass Dissolution ◽  
Gel Layer ◽  
Congruent Dissolution

ABSTRACTAn analytical model is developed to derive diffusion coefficients from the element profiles of the most mobile glass elements. Congruent dissolution is considered as a transient phenomenon and neglected. In the model, altered glass consists of two sublayers: a gel layer at the solution side, and a diffusion layer at the pristine glass side. In both layers, mobile glass elements diffuse towards the solution, while hydrogen/water diffuses towards the pristine glass.Fitting the element profiles of boron, sodium and lithium leads to diffusion coefficients in the diffusion layer, which at 90°C are typically of the order of 10-22m2/s to 10-21m2/s. At 40°C, these diffusion coefficients are typically a factor ten lower. The diffusion coefficients in the gel are by less than a factor two hundred larger than those in the diffusion layer.The diffusion coefficients derived from the profiles in this way are used to predict the dissolution behavior. These predictions, for which a constant value (representing congruent dissolution) is added to the predicted diffusive release, agree reasonably well with the measured dissolution data. Those results support the idea that diffusion determines the long term release of glass matrix elements in synthetic interstitial clay water. Flux conservation at the interface between the gel and the diffusion layer is not consistent with a constant (as a function of time) width of the diffusion layer. Some experimental evidence supports that this width increases with time.

scholarly journals Long-Acting Risperidone Dual Control System: Preparation, Characterization and Evaluation In Vitro and In Vivo

Pharmaceutics ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1210
Author(s):  
Xieguo Yan ◽  
Shiqiang Wang ◽  
Kaoxiang Sun
Keyword(s):  
Drug Loading ◽  
Entrapment Efficiency ◽  
In Vitro Dissolution ◽  
Dissolution Behavior ◽  
In Vivo Evaluation ◽  
Long Term Treatment ◽  
Long Acting

Schizophrenia, a psychiatric disorder, requires long-term treatment; however, large fluctuations in blood drug concentration increase the risk of adverse reactions. We prepared a long-term risperidone (RIS) implantation system that can stabilize RIS release and established in-vitro and in-vivo evaluation systems. Cumulative release, drug loading, and entrapment efficiency were used as evaluation indicators to evaluate the effects of different pore formers, polymer ratios, porogen concentrations, and oil–water ratios on a RIS implant (RIS-IM). We also built a mathematical model to identify the optimized formulation by stepwise regression. We also assessed the crystalline changes, residual solvents, solubility and stability after sterilization, in-vivo polymer degradation, pharmacokinetics, and tissue inflammation in the case of the optimized formulation. The surface of the optimized RIS microspheres was small and hollow with 134.4 ± 3.5 µm particle size, 1.60 SPAN, 46.7% ± 2.3% implant drug loading, and 93.4% entrapment efficiency. The in-vitro dissolution behavior of RIS-IM had zero-order kinetics and stable blood concentration; no lag time was released for over three months. Furthermore, the RIS-IM was not only non-irritating to tissues but also had good biocompatibility and product stability. Long-acting RIS-IMs with microspheres and film coatings can provide a new avenue for treating schizophrenia.

A data-driven XRD analysis protocol for phase identification and phase-fraction prediction of multiphase inorganic compounds

2021 ◽  
Author(s):  
Jin-Woong Lee ◽  
Woon Bae Park ◽  
Minseuk Kim ◽  
Satendra Pal Singh ◽  
Myoungho Pyo ◽  
...  
Keyword(s):  
Deep Learning ◽  
Inorganic Compounds ◽  
Xrd Analysis ◽  
Data Driven ◽  
Phase Fraction ◽  
Phase Identification ◽  
Constituent Phase ◽  
Analysis Protocol

Deep learning (DL) models trained with synthetic XRD data have never accomplished a satisfactory quantitative XRD analysis for the exact prediction of a constituent-phase fraction in unknown multiphase inorganic compounds,...

Shielding behavior and structural role of bismuth oxide in ternary bismuth lead borate glass

2021 ◽  
Vol 0 (0) ◽  
pp. 0-0
Author(s):  
Noha Kattaya ◽  
Amr Abdelghany ◽  
Mahrous Meikhail ◽  
Osama Hemeda ◽  
Mohamed Ali
Keyword(s):  
Bismuth Oxide ◽  
Borate Glass ◽  
Lead Borate ◽  
Structural Role ◽  
Bismuth Lead

scholarly journals Bone Regeneration by Novel Bioactive Glasses Containing Strontium and/or Magnesium: A Preliminary In-Vivo Study

Materials ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 2223 ◽  
Author(s):  
Devis Bellucci ◽  
Valeria Cannillo ◽  
Alexandre Anesi ◽  
Roberta Salvatori ◽  
Luigi Chiarini ◽  
...  
Keyword(s):  
Statistical Significance ◽  
Formation Processes ◽  
Complete Dissolution ◽  
In Vitro Bioactivity ◽  
Bioactive Glasses ◽  
Beneficial Effects ◽  
Glass Dissolution

In this work, a set of novel bioactive glasses have been tested in vivo in an animal model. The new compositions, characterized by an exceptional thermal stability and high in vitro bioactivity, contain strontium and/or magnesium, whose biological benefits are well documented in the literature. To simulate a long-term implant and to study the effect of the complete dissolution of glasses, samples were implanted in the mid-shaft of rabbits’ femur and analyzed 60 days after the surgery; such samples were in undersized powder form. The statistical significance with respect to the type of bioactive glass was analyzed by Kruskal–Wallis test. The results show high levels of bone remodeling, several new bone formations containing granules of calcium phosphate (sometimes with amounts of strontium and/or magnesium), and the absence of adverse effects on bone processes due to the almost complete glass dissolution. In vivo results confirming the cell culture outcomes of a previous study highlighted that these novel bioglasses had osteostimulative effect without adverse skeletal reaction, thus indicating possible beneficial effects on bone formation processes. The presence of strontium in the glasses seems to be particularly interesting.

Perspectives on the Review of AECL's Proposal for Disposing of Canada's Nuclear Fuel Waste

1997 ◽  
Vol 506 ◽  
Author(s):  
K.W. Dormuth ◽  
P.A. Gillespie ◽  
S.H. Whitaker
Keyword(s):  
Nuclear Fuel ◽  
Environmental Assessment ◽  
Geological Disposal ◽  
The Public ◽  
Public Hearings ◽  
Points Of View ◽  
Nuclear Fuel Waste ◽  
Term Management

ABSTRACTA federal Environmental Assessment Panel has completed public hearings on the proposed concept for geological disposal of Canada's nuclear fuel waste. The Panel will make recommendations to assist the governments of Canada and Ontario in reaching decisions on the acceptability of the proposed concept and on the steps that must be taken to ensure the safe long-term management of nuclear fuel waste in Canada. It is instructive to review the background to the public hearings, to consider the issues that have been important in the public review, and to reflect on the opposing points of view presented at the hearings.

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