Abstract
Emergence is complex behavior arising from the interactions of many simple constituents that do not display such behavior independently. Polyamidoxime (PAO) uranium adsorbents show such phenomena, as recent works articulate that the polymer binds uranium differently than the monomeric constituents. In order to investigate the origins of this emergent uranium-binding behavior, we synthesized a series of amidoxime polymers with low polydispersity and small molecules with lengths ranging from 1 to 125 repeat units. Following immersion in a uranyl-containing solution, the local, intermediate, and macroscopic structures were investigated by X-ray absorption fine structure (XAFS) spectroscopy, small angle neutron scattering (SANS), and dynamic light scattering (DLS). Fits of the extended XAFS (EXAFS) region revealed a progressive change in uranium coordination environment as a function of polymer molecular weight, identifying chain length as a driving force in emergent metal binding and resolving the controversy over how amidoxime adsorbents bind uranium.
| Original language | English |
|---|---|
| Pages (from-to) | 554-560 |
| Number of pages | 7 |
| Journal | Physical Chemistry Chemical Physics |
| Volume | 21 |
| Issue number | 2 |
| DOIs | |
| State | Published - 2019 |
Funding
† This manuscript has been co-authored by UT-Battelle, LLC, under contract DE-AC05-00OR22725 with the US Department of Energy (DOE). The U.S. Government is authorized to reproduce and distribute reprints for Government purposes notwithstanding any copyright notation hereon. DOE will provide public access to these results of federally sponsored research in accordance with the DOE Public Access Plan (http://energy.gov/downloads/doe-public-access-plan). ‡ Electronic supplementary information (ESI) available: A document containing general synthetic, characterization, and experimental details; XAFS data collection and processing details; SANS data collection and processing details; supplementary data and figures (pdf). See DOI: 10.1039/c8cp02198h § Current address: Intel Corporation, 2501 NW Century Blvd, Hillsboro, OR 97124, USA. ¶ Current address: ExxonMobil Research & Engineering, 1545 US-22 #1, Annan-dale, NJ 08801, USA. LDE and CWA were supported by the U.S. Department of Energy, Office of Nuclear Energy, under Contract DE-AC05-00OR22725 with Oak Ridge National Laboratory, managed by UT-Battelle, LLC. Research at Oak Ridge National Laboratory’s Spallation Neutron Source and Oak Ridge National Laboratory’s Center for Nanophase Materials Science was sponsored by the Scientific User Facilities Division, Office of Basic Energy Sciences, U.S. Department of Energy. Use of the Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, is supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences under Contract No. DE-AC02-76SF00515. A portion of this research used resources at the Spallation Neutron Source, a U.S. Department of Energy (DOE) Office of Science User Facility operated by the Oak Ridge National Laboratory. This work benefitted from SasView software, originally developed by the DANSE project under NSF award DMR-0520547. This manuscript has been authored by UT-Battelle, LLC under Contract No. DE-AC05-00OR22725 with the U.S. Department of Energy. Polymer characterization was performed at Oak Ridge National Laboratory’s Center for Nanophase Materials Science, which is a DOE Office of Science User Facility. The United States Government retains and the publisher, by accepting the article for publication, acknowledges that the United States Government retains a non-exclusive, paid-up, irrevocable, worldwide license to publish or reproduce the published form of this manuscript, or allow others to do so, for United States Government purposes. The Department of Energy will provide public access to these results of federally sponsored research in accordance with the DOE Public Access Plan (http://energy.gov/downloads/doe-public-access-plan).
| Funders | Funder number |
|---|---|
| Office of Basic Energy Sciences | |
| Scientific User Facilities Division | |
| US Department of Energy | |
| UT-Battelle | |
| National Science Foundation | DMR-0520547 |
| U.S. Department of Energy | |
| Office of Science | |
| Office of Nuclear Energy | DE-AC05-00OR22725 |
| Oak Ridge National Laboratory |