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Title: Assessment of Impacts of Dissolved Organic Matter and Dissolved Iron on the Performance of Amidoxime-Based Adsorbents for Seawater Uranium Extraction

Abstract

Research on extraction of uranium from seawater has been active in recent years because this technology can provide an additional supply of uranium for nuclear fuel from a much larger uranium reservoir (the oceans) and the processes are more environment friendly. One critical challenge of the development of this technology is to make uranium adsorbents perform well not just in the oversimplified laboratory system (e.g. artificial seawater) but also in the complex real seawater matrix, which is comprised of many competing ions and natural organic substances. Here, we conducted a systematic study using a continuous-flow seawater flume system to assess the potential impacts of dissolved organic matter (DOM) and dissolved iron on the uranium uptake performance (including adsorbent reusability) of amidoxime-based adsorbents. In the 28-day exposure, the adsorbent exposed in dissolved Fe-spiked seawater (low DOM/high Fe) and humic acid-spiked seawater (high DOM/high Fe) showed lower uranium adsorption loadings (73% and 56% of adsorption loading, respectively) than the same adsorbent exposed in seawater without spiking (low DOM/low Fe). Interestingly, the uranium adsorption loading of the reused adsorbent (after uranium stripping by a mild bicarbonate elution) in the dissolved Fe-spiked seawater dropped substantially to only 24% of the loading in the unspikedmore » clean seawater counterpart; while not much change was observed in the performance of adsorbent exposed to the humic acid-spiked seawater. From comparison of FTIR signatures of adsorbent before and after the seawater exposure, we found that the amidoxime ligands in the adsorbent exposed to dissolved Fe-spiked seawater had severer degradation than the adsorbents exposed to humic acid-spiked seawater and unspiked clean seawater. Notably, unlike the adsorbent exposed to dissolved Fe-spiked seawater, the adsorbent exposed to humic acid-spiked seawater didn’t adsorb elevated level of Fe compared to the adsorbent in the unspiked clean seawater. This suggests that the species of Fe in the humic acid-spiked seawater (primarily humic acid bound Fe) didn’t interact with amidoxime-based adsorbent; while the Fe species in the Fe-spiked seawater strongly interacted with adsorbent and caused significant degradation of amidoxime ligands. On the other hand, highly variable uranium adsorption loadings were observed in adsorbent in contact with humic acid-spiked seawater, but not in the adsorbents exposed to dissolved Fe-spiked seawater and seawater without spike. Our observations thus indicate that seawater receiving high inputs of DOM and dissolved Fe, such as coastal waters, is not ideal for efficient extraction of uranium.« less

Authors:
 [1];  [2]; ORCiD logo [1];  [1];  [3];  [1];  [2]; ORCiD logo [1]
  1. BATTELLE (PACIFIC NW LAB)
  2. University of Idaho
  3. Oak Ridge National Laboatory
Publication Date:
Research Org.:
Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1543276
Report Number(s):
PNNL-SA-141051
DOE Contract Number:  
AC05-76RL01830
Resource Type:
Journal Article
Journal Name:
Industrial and Engineering Chemistry Research
Additional Journal Information:
Journal Volume: 58; Journal Issue: 19
Country of Publication:
United States
Language:
English
Subject:
Uranium, Seawater, amidoxime-based adsorbents, dissolved organic matter

Citation Formats

Kuo, Li-Jung, Pan, H B., Strivens, Jonathan E., Schlafer, Nicholas J., Janke, Christopher J., Wood, Jordana R., Wai, Chien M., and Gill, Gary A. Assessment of Impacts of Dissolved Organic Matter and Dissolved Iron on the Performance of Amidoxime-Based Adsorbents for Seawater Uranium Extraction. United States: N. p., 2019. Web. doi:10.1021/acs.iecr.9b00670.
Kuo, Li-Jung, Pan, H B., Strivens, Jonathan E., Schlafer, Nicholas J., Janke, Christopher J., Wood, Jordana R., Wai, Chien M., & Gill, Gary A. Assessment of Impacts of Dissolved Organic Matter and Dissolved Iron on the Performance of Amidoxime-Based Adsorbents for Seawater Uranium Extraction. United States. doi:10.1021/acs.iecr.9b00670.
Kuo, Li-Jung, Pan, H B., Strivens, Jonathan E., Schlafer, Nicholas J., Janke, Christopher J., Wood, Jordana R., Wai, Chien M., and Gill, Gary A. Wed . "Assessment of Impacts of Dissolved Organic Matter and Dissolved Iron on the Performance of Amidoxime-Based Adsorbents for Seawater Uranium Extraction". United States. doi:10.1021/acs.iecr.9b00670.
@article{osti_1543276,
title = {Assessment of Impacts of Dissolved Organic Matter and Dissolved Iron on the Performance of Amidoxime-Based Adsorbents for Seawater Uranium Extraction},
author = {Kuo, Li-Jung and Pan, H B. and Strivens, Jonathan E. and Schlafer, Nicholas J. and Janke, Christopher J. and Wood, Jordana R. and Wai, Chien M. and Gill, Gary A.},
abstractNote = {Research on extraction of uranium from seawater has been active in recent years because this technology can provide an additional supply of uranium for nuclear fuel from a much larger uranium reservoir (the oceans) and the processes are more environment friendly. One critical challenge of the development of this technology is to make uranium adsorbents perform well not just in the oversimplified laboratory system (e.g. artificial seawater) but also in the complex real seawater matrix, which is comprised of many competing ions and natural organic substances. Here, we conducted a systematic study using a continuous-flow seawater flume system to assess the potential impacts of dissolved organic matter (DOM) and dissolved iron on the uranium uptake performance (including adsorbent reusability) of amidoxime-based adsorbents. In the 28-day exposure, the adsorbent exposed in dissolved Fe-spiked seawater (low DOM/high Fe) and humic acid-spiked seawater (high DOM/high Fe) showed lower uranium adsorption loadings (73% and 56% of adsorption loading, respectively) than the same adsorbent exposed in seawater without spiking (low DOM/low Fe). Interestingly, the uranium adsorption loading of the reused adsorbent (after uranium stripping by a mild bicarbonate elution) in the dissolved Fe-spiked seawater dropped substantially to only 24% of the loading in the unspiked clean seawater counterpart; while not much change was observed in the performance of adsorbent exposed to the humic acid-spiked seawater. From comparison of FTIR signatures of adsorbent before and after the seawater exposure, we found that the amidoxime ligands in the adsorbent exposed to dissolved Fe-spiked seawater had severer degradation than the adsorbents exposed to humic acid-spiked seawater and unspiked clean seawater. Notably, unlike the adsorbent exposed to dissolved Fe-spiked seawater, the adsorbent exposed to humic acid-spiked seawater didn’t adsorb elevated level of Fe compared to the adsorbent in the unspiked clean seawater. This suggests that the species of Fe in the humic acid-spiked seawater (primarily humic acid bound Fe) didn’t interact with amidoxime-based adsorbent; while the Fe species in the Fe-spiked seawater strongly interacted with adsorbent and caused significant degradation of amidoxime ligands. On the other hand, highly variable uranium adsorption loadings were observed in adsorbent in contact with humic acid-spiked seawater, but not in the adsorbents exposed to dissolved Fe-spiked seawater and seawater without spike. Our observations thus indicate that seawater receiving high inputs of DOM and dissolved Fe, such as coastal waters, is not ideal for efficient extraction of uranium.},
doi = {10.1021/acs.iecr.9b00670},
journal = {Industrial and Engineering Chemistry Research},
number = 19,
volume = 58,
place = {United States},
year = {2019},
month = {5}
}