Sulfur Speciation in Biochars by Very High Resolution Benchtop Kα X-ray Emission Spectroscopy
The analytical chemistry of sulfur-containing materials poses substantial technical challenges, especially due to the limitations of 33S NMR and the time-intensive preparations required for wet-chemistry analyses. A number of prior studies have found that synchrotron-based X-ray absorption near edge structure (XANES) measurements can give detailed speciation of sulfur chemistry in such cases. However, due to the obvious access limitations, synchrotron XANES of sulfur cannot be part of routine analytical practice across the chemical sciences community. Here, in a study of the sulfur chemistry in biochars, we compare and contrast the chemical inferences available from synchrotron XANES with that given by benchtop, extremely high resolution wavelength-dispersive X-ray fluorescence (WD-XRF) spectroscopy, also often called X-ray emission spectroscopy (XES). While the XANES spectra have higher total information content, often giving differentiation between different moieties having the same oxidation state, the lower sensitivity of the S Ka XES to coordination and local structure provides pragmatic benefit for the more limited goal of quantifying the S oxidation state distribution. Within that constrained metric, we find good agreement between the two methods. As the sulfur concentrations were as low as 150 ppm, these measurements provide proof-of-principle for characterization of the sulfur chemistry of biochars and potentialmore »
- Authors:
-
[1]
; [1]
; [2]
- Univ. of Washington, Seattle, WA (United States)
- National Renewable Energy Lab. (NREL), Golden, CO (United States)
- Publication Date:
- Report Number(s):
- NREL/JA-5100-71758
Journal ID: ISSN 1089-5639
- Grant/Contract Number:
- AC36-08GO28308
- Type:
- Accepted Manuscript
- Journal Name:
- Journal of Physical Chemistry. A, Molecules, Spectroscopy, Kinetics, Environment, and General Theory
- Additional Journal Information:
- Journal Volume: 122; Journal Issue: 23; Journal ID: ISSN 1089-5639
- Publisher:
- American Chemical Society
- Research Org:
- National Renewable Energy Lab. (NREL), Golden, CO (United States)
- Sponsoring Org:
- USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
- Country of Publication:
- United States
- Language:
- English
- Subject:
- 37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; sulfur chemistry; biochars; spectroscopy
- OSTI Identifier:
- 1454908
Holden, William M., Seidler, Gerald T., and Cheah, Singfoong. Sulfur Speciation in Biochars by Very High Resolution Benchtop Kα X-ray Emission Spectroscopy. United States: N. p.,
Web. doi:10.1021/acs.jpca.8b02816.
Holden, William M., Seidler, Gerald T., & Cheah, Singfoong. Sulfur Speciation in Biochars by Very High Resolution Benchtop Kα X-ray Emission Spectroscopy. United States. doi:10.1021/acs.jpca.8b02816.
Holden, William M., Seidler, Gerald T., and Cheah, Singfoong. 2018.
"Sulfur Speciation in Biochars by Very High Resolution Benchtop Kα X-ray Emission Spectroscopy". United States.
doi:10.1021/acs.jpca.8b02816.
@article{osti_1454908,
title = {Sulfur Speciation in Biochars by Very High Resolution Benchtop Kα X-ray Emission Spectroscopy},
author = {Holden, William M. and Seidler, Gerald T. and Cheah, Singfoong},
abstractNote = {The analytical chemistry of sulfur-containing materials poses substantial technical challenges, especially due to the limitations of 33S NMR and the time-intensive preparations required for wet-chemistry analyses. A number of prior studies have found that synchrotron-based X-ray absorption near edge structure (XANES) measurements can give detailed speciation of sulfur chemistry in such cases. However, due to the obvious access limitations, synchrotron XANES of sulfur cannot be part of routine analytical practice across the chemical sciences community. Here, in a study of the sulfur chemistry in biochars, we compare and contrast the chemical inferences available from synchrotron XANES with that given by benchtop, extremely high resolution wavelength-dispersive X-ray fluorescence (WD-XRF) spectroscopy, also often called X-ray emission spectroscopy (XES). While the XANES spectra have higher total information content, often giving differentiation between different moieties having the same oxidation state, the lower sensitivity of the S Ka XES to coordination and local structure provides pragmatic benefit for the more limited goal of quantifying the S oxidation state distribution. Within that constrained metric, we find good agreement between the two methods. As the sulfur concentrations were as low as 150 ppm, these measurements provide proof-of-principle for characterization of the sulfur chemistry of biochars and potential applications to other areas such as soils, batteries, catalysts, and fossil fuels and their combustion products.},
doi = {10.1021/acs.jpca.8b02816},
journal = {Journal of Physical Chemistry. A, Molecules, Spectroscopy, Kinetics, Environment, and General Theory},
number = 23,
volume = 122,
place = {United States},
year = {2018},
month = {5}
}