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Title: Investigations into the Reusability of Amidoxime-Based Polymeric Adsorbents for Seawater Uranium Extraction

Abstract

The ability to re-use amidoxime-based polymeric adsorbents is a critical component in reducing the overall cost of the technology to extract uranium from seawater. This report describes an evaluation of adsorbent reusability in multiple re-use (adsorption/stripping) cycles in real seawater exposures with potassium bicarbonate (KHCO3) elution using several amidoxime-based polymeric adsorbents. The KHCO3 elution technique achieved ~100% recovery of uranium adsorption capacity in the first re-use. Subsequent re-uses showed significant drops in adsorption capacity. After the 4th re-use with the ORNL AI8 adsorbent, the 56-day adsorption capacity dropped to 28% of its original capacity. FTIR spectra revealed that there was a conversion of the amidoxime ligands to carboxylate groups during extended seawater exposure, becoming more significant with longer the exposure time. Ca and Mg adsorption capacities also increased with each re-use cycle supporting the hypothesis that long term exposure resulted in converting amidoxime to carboxylate, enhancing the adsorption of Ca and Mg. Shorter seawater exposure (adsorption/stripping) cycles (28 vs. 42 days) had higher adsorption capacities after re-use, but the shorter exposure cycle time did not produce an overall better performance in terms of cumulative exposure time. Recovery of uranium capacity in re-uses may also vary across different adsorbent formulations. Throughmore » multiple re-use the adsorbent AI8 can harvest 10 g uranium/kg adsorbent in ~140 days, using a 28-day adsorption/stripping cycle, a performance much better than would be achieved with a single use of the adsorbent through very long-term exposure (saturation capacity = 7.4 g U/kg adsorbent). A time dependent seawater exposure model to evaluate the cost associated with reusing amidoxime-based adsorbents in real seawater exposures was developed. The cost to extract uranium from seawater ranged from $610-830/kg U was predicted. Model simulation suggests that a short seawater exposure cycle (< 15 days) is the optimal deployment period for lower uranium production cost in seawater uranium mining.« less

Authors:
ORCiD logo [1];  [2];  [2];  [3];  [3]; ORCiD logo [1];  [4];  [4]; ORCiD logo [4];  [1];  [1];  [1]
  1. Marine Sciences Laboratory, Pacific Northwest National Laboratory, Sequim, Washington 98382, United States
  2. Department of Chemistry, University of Idaho, Moscow, Idaho 83844, United States
  3. Nuclear and Radiation Engineering Program, The University of Texas at Austin, Austin, Texas 78712, United States
  4. Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, Tennessee 37831, United States
Publication Date:
Research Org.:
Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
Sponsoring Org.:
USDOE Office of Nuclear Energy (NE)
OSTI Identifier:
1406714
Report Number(s):
PNNL-SA-127685
Journal ID: ISSN 0888-5885; AF5855000
DOE Contract Number:  
AC05-76RL01830
Resource Type:
Journal Article
Resource Relation:
Journal Name: Industrial and Engineering Chemistry Research; Journal Volume: 56; Journal Issue: 40
Country of Publication:
United States
Language:
English

Citation Formats

Kuo, Li-Jung, Pan, Horng-Bin, Wai, Chien M., Byers, Margaret F., Schneider, Erich, Strivens, Jonathan E., Janke, Christopher J., Das, Sadananda, Mayes, Richard T., Wood, Jordana R., Schlafer, Nicholas, and Gill, Gary A.. Investigations into the Reusability of Amidoxime-Based Polymeric Adsorbents for Seawater Uranium Extraction. United States: N. p., 2017. Web. doi:10.1021/acs.iecr.7b02893.
Kuo, Li-Jung, Pan, Horng-Bin, Wai, Chien M., Byers, Margaret F., Schneider, Erich, Strivens, Jonathan E., Janke, Christopher J., Das, Sadananda, Mayes, Richard T., Wood, Jordana R., Schlafer, Nicholas, & Gill, Gary A.. Investigations into the Reusability of Amidoxime-Based Polymeric Adsorbents for Seawater Uranium Extraction. United States. doi:10.1021/acs.iecr.7b02893.
Kuo, Li-Jung, Pan, Horng-Bin, Wai, Chien M., Byers, Margaret F., Schneider, Erich, Strivens, Jonathan E., Janke, Christopher J., Das, Sadananda, Mayes, Richard T., Wood, Jordana R., Schlafer, Nicholas, and Gill, Gary A.. Fri . "Investigations into the Reusability of Amidoxime-Based Polymeric Adsorbents for Seawater Uranium Extraction". United States. doi:10.1021/acs.iecr.7b02893.
@article{osti_1406714,
title = {Investigations into the Reusability of Amidoxime-Based Polymeric Adsorbents for Seawater Uranium Extraction},
author = {Kuo, Li-Jung and Pan, Horng-Bin and Wai, Chien M. and Byers, Margaret F. and Schneider, Erich and Strivens, Jonathan E. and Janke, Christopher J. and Das, Sadananda and Mayes, Richard T. and Wood, Jordana R. and Schlafer, Nicholas and Gill, Gary A.},
abstractNote = {The ability to re-use amidoxime-based polymeric adsorbents is a critical component in reducing the overall cost of the technology to extract uranium from seawater. This report describes an evaluation of adsorbent reusability in multiple re-use (adsorption/stripping) cycles in real seawater exposures with potassium bicarbonate (KHCO3) elution using several amidoxime-based polymeric adsorbents. The KHCO3 elution technique achieved ~100% recovery of uranium adsorption capacity in the first re-use. Subsequent re-uses showed significant drops in adsorption capacity. After the 4th re-use with the ORNL AI8 adsorbent, the 56-day adsorption capacity dropped to 28% of its original capacity. FTIR spectra revealed that there was a conversion of the amidoxime ligands to carboxylate groups during extended seawater exposure, becoming more significant with longer the exposure time. Ca and Mg adsorption capacities also increased with each re-use cycle supporting the hypothesis that long term exposure resulted in converting amidoxime to carboxylate, enhancing the adsorption of Ca and Mg. Shorter seawater exposure (adsorption/stripping) cycles (28 vs. 42 days) had higher adsorption capacities after re-use, but the shorter exposure cycle time did not produce an overall better performance in terms of cumulative exposure time. Recovery of uranium capacity in re-uses may also vary across different adsorbent formulations. Through multiple re-use the adsorbent AI8 can harvest 10 g uranium/kg adsorbent in ~140 days, using a 28-day adsorption/stripping cycle, a performance much better than would be achieved with a single use of the adsorbent through very long-term exposure (saturation capacity = 7.4 g U/kg adsorbent). A time dependent seawater exposure model to evaluate the cost associated with reusing amidoxime-based adsorbents in real seawater exposures was developed. The cost to extract uranium from seawater ranged from $610-830/kg U was predicted. Model simulation suggests that a short seawater exposure cycle (< 15 days) is the optimal deployment period for lower uranium production cost in seawater uranium mining.},
doi = {10.1021/acs.iecr.7b02893},
journal = {Industrial and Engineering Chemistry Research},
number = 40,
volume = 56,
place = {United States},
year = {Fri Sep 29 00:00:00 EDT 2017},
month = {Fri Sep 29 00:00:00 EDT 2017}
}