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Title: Organic layer formation and sorption of U(VI) on acetamide diethylphosphonate-functionalized mesoporous silica

Abstract

Acetamide diethylphosphonate (AcPhos)-functionalized silica has been shown to have a high affinity for U(vi) in pH 2-3 nitric acid. Previous work with AcPhos-functionalized silica has focused on actinide and lanthanide extraction under various conditions, but has shown poor reproducibility in the functionalization process. For this work, four AcPhos-functionalized SBA-15 materials were synthesized and evaluated based on their U(vi) sorption capacity and their stability in nitric acid. Materials synthesized using pyridine as a basic catalyst were shown to form a greater fraction of polymeric structures at the silica surface, which correlated with higher structural integrity upon contact with acidic solutions. Single-pulse 31P and 1H NMR spectra of these materials show evidence of phosphonic acid groups, as well as hydrogen-bonding interactions either between ligands or with the silica surface. Additionally, these materials were found to have significantly higher U(vi) sorption capacities and K eq values than the materials synthesized without pyridine, most likely due to the ion-exchange properties of the phosphonic acid groups. The 31P- 31P DQ-DRENAR NMR technique was used to compare the average strength of dipolar coupling interactions between phosphorus atoms for the four materials. Because the strength of dipolar coupling interactions depends on the number and proximity of neighboringmore » spins, this technique provides information about the average density of ligands on the surface. Finally, the conventional functionalization procedure yielded materials with the lowest average surface ligand density, while those using extended reaction times and the pyridine base catalyst yielded materials with higher surface ligand densities.« less

Authors:
ORCiD logo [1];  [2];  [2];  [3]
  1. Univ. of California, Berkeley, CA (United States). Dept. of Chemistry
  2. Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States). Glenn T. Seaborg Inst., Physical and Life Sciences Directorate
  3. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Chemical Sciences Division
Publication Date:
Research Org.:
Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
Sponsoring Org.:
USDOE National Nuclear Security Administration (NNSA); National Science Foundation (NSF)
OSTI Identifier:
1480760
Grant/Contract Number:  
AC02-05CH11231; NA0001978; AC52-07NA27344; DGE1106400
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Dalton Transactions
Additional Journal Information:
Journal Volume: 46; Journal Issue: 16; Journal ID: ISSN 1477-9226
Publisher:
Royal Society of Chemistry
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY

Citation Formats

Uribe, Eva C., Mason, Harris E., Shusterman, Jennifer A., and Lukens, Wayne W. Organic layer formation and sorption of U(VI) on acetamide diethylphosphonate-functionalized mesoporous silica. United States: N. p., 2017. Web. doi:10.1039/c7dt00362e.
Uribe, Eva C., Mason, Harris E., Shusterman, Jennifer A., & Lukens, Wayne W. Organic layer formation and sorption of U(VI) on acetamide diethylphosphonate-functionalized mesoporous silica. United States. doi:10.1039/c7dt00362e.
Uribe, Eva C., Mason, Harris E., Shusterman, Jennifer A., and Lukens, Wayne W. Tue . "Organic layer formation and sorption of U(VI) on acetamide diethylphosphonate-functionalized mesoporous silica". United States. doi:10.1039/c7dt00362e. https://www.osti.gov/servlets/purl/1480760.
@article{osti_1480760,
title = {Organic layer formation and sorption of U(VI) on acetamide diethylphosphonate-functionalized mesoporous silica},
author = {Uribe, Eva C. and Mason, Harris E. and Shusterman, Jennifer A. and Lukens, Wayne W.},
abstractNote = {Acetamide diethylphosphonate (AcPhos)-functionalized silica has been shown to have a high affinity for U(vi) in pH 2-3 nitric acid. Previous work with AcPhos-functionalized silica has focused on actinide and lanthanide extraction under various conditions, but has shown poor reproducibility in the functionalization process. For this work, four AcPhos-functionalized SBA-15 materials were synthesized and evaluated based on their U(vi) sorption capacity and their stability in nitric acid. Materials synthesized using pyridine as a basic catalyst were shown to form a greater fraction of polymeric structures at the silica surface, which correlated with higher structural integrity upon contact with acidic solutions. Single-pulse 31P and 1H NMR spectra of these materials show evidence of phosphonic acid groups, as well as hydrogen-bonding interactions either between ligands or with the silica surface. Additionally, these materials were found to have significantly higher U(vi) sorption capacities and Keq values than the materials synthesized without pyridine, most likely due to the ion-exchange properties of the phosphonic acid groups. The 31P-31P DQ-DRENAR NMR technique was used to compare the average strength of dipolar coupling interactions between phosphorus atoms for the four materials. Because the strength of dipolar coupling interactions depends on the number and proximity of neighboring spins, this technique provides information about the average density of ligands on the surface. Finally, the conventional functionalization procedure yielded materials with the lowest average surface ligand density, while those using extended reaction times and the pyridine base catalyst yielded materials with higher surface ligand densities.},
doi = {10.1039/c7dt00362e},
journal = {Dalton Transactions},
number = 16,
volume = 46,
place = {United States},
year = {Tue Mar 28 00:00:00 EDT 2017},
month = {Tue Mar 28 00:00:00 EDT 2017}
}

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Works referenced in this record:

Adsorption of Gases in Multimolecular Layers
journal, February 1938

  • Brunauer, Stephen; Emmett, P. H.; Teller, Edward
  • Journal of the American Chemical Society, Vol. 60, Issue 2, p. 309-319
  • DOI: 10.1021/ja01269a023