The Structural Role of <scp>Zn</scp> in Nuclear Waste Glasses

Cassingham, Nathan J.; Stennett, Martin C.; Bingham, Paul A.; Hyatt, Neil C.; Aquilanti, Giuliana

doi:10.1111/j.2041-1294.2011.00067.x

Cited by 26 publications

(29 citation statements)

References 23 publications

(47 reference statements)

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“…The second major peak corresponds to the O–O bond length at 2.61 Å. With the addition of ZnO, the PDF differs slightly: an additional Zn–O peak is observed at 1.96 Å, which compares favorably with the experimentally derived bond length of 1.95 Å observed for tetrahedral zinc in the same composition . Notably, the widths of the Si–O and O–O peaks remain unaltered.…”

Section: Resultssupporting

confidence: 60%

“…To combat this problem, it has been proposed to add zinc to the current glass composition. A number of experimental studies have shown that the addition of even small quantities of zinc oxide to the nuclear glass retards aqueous dissolution of both borosilicate and simpler silicate glass compositions . While many of the structural effects of zinc additions can be studied experimentally, no conclusive mechanism for the observed increase in glass durability has been identified.…”

Section: Introductionmentioning

confidence: 99%

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Predicted Mechanism for Enhanced Durability of Zinc Containing Silicate Glasses

2013

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Experimental studies have reported that zinc oxide improves the durability of glasses used for nuclear waste immobilization. Here, molecular dynamics simulations are used to predict the atomic structures of sodium silicate glass with and without zinc. A simulated melt-quench procedure is used to generate glass structures. Pair distribution functions, ring size distributions, and alkali clustering are then examined. This allows insights into the structural role of zinc oxide within the glass and helps distinguish between its reported functions as a network former and a network modifier. Changes in the sodium ion distribution and clustering behavior within the glass are observed, due to zinc oxide addition. This affects the local and intermediate-range structure of the glass and provides a possible explanation for enhanced durability.

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Section: Resultssupporting

confidence: 60%

Section: Introductionmentioning

confidence: 99%

Predicted Mechanism for Enhanced Durability of Zinc Containing Silicate Glasses

2013

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“…Also, the electrostatic attraction of the excess of negative charge in the (ZnO 4 ) 2− tetrahedral should restrain further the mobility of Na + ions [41]. In general, zinc has been shown to exhibit a marked preference for square planar complexes in simple alkali silicate glasses [43] and therefore, in most cases of zinc-containing 45S5 BG, Zn 2+ can be a fourcoordinated weak network former [80]. Kapoor et al [44] studied the effect of zinc on the structure of melt-quenched alkali-free CaO-MgO-SiO 2 -P 2 O 5 -CaF 2 based glass system.…”

Section: Structure Physical and Mechanical Propertiesmentioning

confidence: 99%

Zinc-containing bioactive glasses for bone regeneration, dental and orthopedic applications

Balasubramanian¹,

Strobel²,

Kneser³

et al. 2015

Biomedical Glasses

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Zinc is a vital and beneficial trace element found in the human body. Though found in small proportions, zinc performs a variety of functions in relation to the immune system, cell division, fertility and the body growth and maintenance. In particular, zinc is proven to be a necessary element for the formation, mineralization, development and maintenance of healthy bones. Considering this attractive attributes of zinc, recent research has widely focused on using zinc along with silicate-based bioactive glasses for bone tissue engineering applications. This paper reviews relevant literature discussing the significance of zinc in the human body, along with its ability to enhance antibacterial effects, bioactivity and distinct physical, structural and mechanical properties of bioactive glasses. In this context, even if the present analysis is not meant to be exhaustive and only representative studies are discussed, literature results confirm that it is essential to understand the properties of zinc-containing bioactive glasses with respect to their in vitro biological behavior, possible cytotoxic effects and degradation characteristics to be able to effectively apply these glasses in bone regeneration strategies. Topics attracting increasing research efforts in this field are elaborated in detail in this review, including a summary of the structural, physical, biological and mechanical properties of zinc-containing bioactive glasses. This paper also presents an overview of the various applications in which zinc-containing bioactive glasses are considered for use as bone tissue scaffolds, bone filling granules, bioactive coatings and bone cements, and advances and remaining challenges are highlighted.

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“…B 2 O 3 is a glass forming oxide, TeO 2 is a conditional glass former, however, the structural role of zinc in such glasses is the subject of some controversy with evidence for behavior as a network former or a network modifier. Both Zachariasen and Warren's theory of glass structureand Dietzel's crystal field theory classify zinc as a network intermediate, i.e., able to adopt both network former and modifier roles depending upon glass matrix (Cassingham et al, 2010). Sm 2 O 3 is a modifier in the network, with these chemicals in the glass matrix, a low rate of crystallization, moisture resistant, stable and transparent glasses could be achieved.…”

Section: Erjmentioning

confidence: 99%

COMPOSITION DEPENDENT STRUCTURAL AND THERMAL PROPERTIES OF SM<sub>2</sub>O<sub>3</sub> DOPED ZINC FLUOROBORATE GLASSES

Ajithkumar¹

2013

Energy Research Journal

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Glasses based on Sm 3+ doped zinc fluoroborate have been synthesized and characterized. Formation of glass has been investigated in the 30 ZnF 2 -20 TeO 2 -(50-x) B 2 O 3 -x Sm 2 O 3 matrix. Fast quenching is required to prevent melt crystallization and adequate heat treatment to diminish thermal stress, which results in an efficient amorphous material. The Differential Scanning Calorimeter (DSC), Scanning Electron Microscopy (SEM), Energy Dispersive X-ray Analysis (EDAX), stability, density and refractive index have been recorded, calculated, measured and analyzed for the glass samples with different concentrations of Sm 3+ ranging between 0 to 3 mol%. Density increases as dopant concentration increases and glass transition temperature T g ranges between 395 and 420ºC. The increase of molar volume with Sm 2 O 3 content indicates that the extension of glass network is due to the increase of the number of NBOs. The results found in this investigation showed that the refractive index of glass does not only depend on the density but also depends on the electronic polarizability of the glass. The increasing stability of the glass samples shows that they are thermally resistant. The presence of NBOs in the glass network is also approved by the decrease in glass transition temperature (T g ). The variation of the properties with different composition of dopant plays a dominant role in determining a good host material in the field of optics and photonics.

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The Structural Role of Zn in Nuclear Waste Glasses

Cited by 26 publications

References 23 publications

Predicted Mechanism for Enhanced Durability of Zinc Containing Silicate Glasses

Predicted Mechanism for Enhanced Durability of Zinc Containing Silicate Glasses

Zinc-containing bioactive glasses for bone regeneration, dental and orthopedic applications

COMPOSITION DEPENDENT STRUCTURAL AND THERMAL PROPERTIES OF SM<sub>2</sub>O<sub>3</sub> DOPED ZINC FLUOROBORATE GLASSES

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