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Title: Sol–Gel Synthesis and Characterization of Gels with Compositions Relevant to Hydrated Glass Alteration Layers

Abstract

During the processes associated with glass corrosion, porous hydrated glass alteration layers typically form upon exposure to aqueous conditions for extended time periods. The impacts of the alteration layer on glass durability have not been agreed upon in the glass science community. In particular, the formation mechanisms of hydrated glass alteration layers are still largely unknown and require further investigation, but these layers often require months to years to develop and are often too thin to adequately characterize. Meanwhile, sol–gel-derived silicate gels are relatively easy to synthesize in bulk with custom compositions relevant to hydrated glass alteration layers. If alteration layers and synthetic silicate gels demonstrate physical and chemical properties that are sufficiently similar, synthetic silicate gels could be used as analogues for hydrated glass alteration layers in future studies. However, synthetic gels must first be prepared and evaluated before comparisons between glass alteration layers and synthetic silicate gels can be made. This work focuses entirely on the synthesis and observed physical properties of synthetic silicate gels. A future work will compare the characteristics of synthetic gels described in this work with altered waste glass formed in similar pH environments. In this study, synthetic gels were made with custom compositionsmore » at various pH values to evaluate the effect of pH on gel structure and morphology. Several other variables were examined also, such as composition, drying, and aging. Gels were produced by sequential additions of organometallic precursors in a single container. Gels were analyzed with several techniques including small-angle X-ray scattering, gas adsorption, and He pycnometry to determine the effects of the variables on physical properties. Results show that gels prepared at pH 3 consistently contained fewer primary particles with diameters larger than 7.2 nm and fewer pores with diameters larger than 30 nm compared to gels synthesized at pH 7 and 9. Composition was shown to have no discernible effect on primary particle and pore sizes at any pH.« less

Authors:
ORCiD logo [1]; ORCiD logo [2];  [2]
  1. Energy and Environment Directorate, Pacific Northwest National Laboratory, Richland, Washington 99352, United States; Chemistry Department, Washington State University, Pullman, Washington 99164, United States
  2. Chemistry Department, Washington State University, Pullman, Washington 99164, United States
Publication Date:
Research Org.:
Pacific Northwest National Laboratory; Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
Sponsoring Org.:
USDOE Office of Environmental Management (EM); USDOE Office of Nuclear Energy (NE)
OSTI Identifier:
1566905
Alternate Identifier(s):
OSTI ID: 1569693
Grant/Contract Number:  
AC02-06CH11357; AC06-76RL01830
Resource Type:
Published Article
Journal Name:
ACS Omega
Additional Journal Information:
Journal Volume: 4; Journal Issue: 15; Journal ID: ISSN 2470-1343
Publisher:
American Chemical Society (ACS)
Country of Publication:
United States
Language:
English

Citation Formats

Reiser, Joelle T., Ryan, Joseph V., and Wall, Nathalie A. Sol–Gel Synthesis and Characterization of Gels with Compositions Relevant to Hydrated Glass Alteration Layers. United States: N. p., 2019. Web. doi:10.1021/acsomega.9b00491.
Reiser, Joelle T., Ryan, Joseph V., & Wall, Nathalie A. Sol–Gel Synthesis and Characterization of Gels with Compositions Relevant to Hydrated Glass Alteration Layers. United States. doi:10.1021/acsomega.9b00491.
Reiser, Joelle T., Ryan, Joseph V., and Wall, Nathalie A. Wed . "Sol–Gel Synthesis and Characterization of Gels with Compositions Relevant to Hydrated Glass Alteration Layers". United States. doi:10.1021/acsomega.9b00491.
@article{osti_1566905,
title = {Sol–Gel Synthesis and Characterization of Gels with Compositions Relevant to Hydrated Glass Alteration Layers},
author = {Reiser, Joelle T. and Ryan, Joseph V. and Wall, Nathalie A.},
abstractNote = {During the processes associated with glass corrosion, porous hydrated glass alteration layers typically form upon exposure to aqueous conditions for extended time periods. The impacts of the alteration layer on glass durability have not been agreed upon in the glass science community. In particular, the formation mechanisms of hydrated glass alteration layers are still largely unknown and require further investigation, but these layers often require months to years to develop and are often too thin to adequately characterize. Meanwhile, sol–gel-derived silicate gels are relatively easy to synthesize in bulk with custom compositions relevant to hydrated glass alteration layers. If alteration layers and synthetic silicate gels demonstrate physical and chemical properties that are sufficiently similar, synthetic silicate gels could be used as analogues for hydrated glass alteration layers in future studies. However, synthetic gels must first be prepared and evaluated before comparisons between glass alteration layers and synthetic silicate gels can be made. This work focuses entirely on the synthesis and observed physical properties of synthetic silicate gels. A future work will compare the characteristics of synthetic gels described in this work with altered waste glass formed in similar pH environments. In this study, synthetic gels were made with custom compositions at various pH values to evaluate the effect of pH on gel structure and morphology. Several other variables were examined also, such as composition, drying, and aging. Gels were produced by sequential additions of organometallic precursors in a single container. Gels were analyzed with several techniques including small-angle X-ray scattering, gas adsorption, and He pycnometry to determine the effects of the variables on physical properties. Results show that gels prepared at pH 3 consistently contained fewer primary particles with diameters larger than 7.2 nm and fewer pores with diameters larger than 30 nm compared to gels synthesized at pH 7 and 9. Composition was shown to have no discernible effect on primary particle and pore sizes at any pH.},
doi = {10.1021/acsomega.9b00491},
journal = {ACS Omega},
number = 15,
volume = 4,
place = {United States},
year = {2019},
month = {9}
}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record
DOI: 10.1021/acsomega.9b00491

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