A multi-method characterization of natural terrestrial birnessites
- Pennsylvania State Univ., University Park, PA (United States). Dept. of Geosciences; La Salle Univ., Philadelphia, PA (United States). Dept. of Biology
- Smithsonian Institute, Washington, DC (United States). Dept. of Mineral Sciences
- Pennsylvania State Univ., University Park, PA (United States). Dept. of Geosciences
- Univ. of Minnesota, Minneapolis, MN (United States). Dept. of Earth and Environmental Sciences
- Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
- Pennsylvania State Univ., University Park, PA (United States). Dept. of Civil and Environmental Engineering
With a focus on a large set of natural birnessites collected from terrestrial, freshwater systems, in this study we applied and compared the capabilities of X-ray diffraction (XRD), extended X-ray absorption fine structure (EXAFS), Fourier-transform infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS) to characterize crystal structure and chemistry. Using XRD, we successfully identified 3 of the 11 natural birnessite samples as hexagonal ranciéite-like phases, but the remaining samples yielded less interpretable “3-line” diffraction patterns with broad, asymmetrical peaks at d-spacings of ~7.2, ~2.4, and ~1.4 Å. EXAFS analysis suggested that many of these samples had characteristics of both triclinic and hexagonal birnessite. However, application of EXAFS to the ranciéite-like phases yielded unreasonably high concentrations of triclinic birnessite as an intergrowth, calling into question the use of synthetic hexagonal H-birnessite as an appropriate standard in the linear combination fitting of EXAFS data for natural birnessites. FTIR spectroscopy of the “3-line” birnessite samples successfully distinguished triclinic and hexagonal constituents, and analyses of peak positions suggested that natural birnessites occur as a full spectrum of triclinic and hexagonal intergrowths. XPS analysis of these samples revealed that higher Mn3+ concentrations relative to Mn2+ and Mn4+ are correlated to increased proportions of triclinic birnessite.
- Research Organization:
- Pacific Northwest National Laboratory (PNNL), Richland, WA (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC), Basic Energy Sciences (BES). Chemical Sciences, Geosciences & Biosciences Division; USDOE Office of Science (SC), Biological and Environmental Research (BER); National Science Foundation (NSF)
- Grant/Contract Number:
- AC05-76RL01830; AC02-06CH11357
- OSTI ID:
- 1673587
- Alternate ID(s):
- OSTI ID: 1632888
- Report Number(s):
- PNNL-SA--149385; {"","Journal ID: ISSN 0003-004X"}
- Journal Information:
- American Mineralogist, Journal Name: American Mineralogist Journal Issue: 6 Vol. 105; ISSN 0003-004X
- Publisher:
- Mineralogical Society of AmericaCopyright Statement
- Country of Publication:
- United States
- Language:
- English
Similar Records
Effects of pH and Ca exchange on the structure and redox state of synthetic Na-birnessite
Zerovalent Copper Intercalated Birnessite as a Cathode for Lithium Ion Batteries: Extending Cycle Life
Related Subjects
Birnessite
crystal chemistry
crystal structure
crystal systems
electron microscopy data
electron probe data
EXAFS
FTIR spectra
hexagonal system
infrared spectra
manganese minerals
manganese oxides
oxides
SEM data
spectra
spectroscopy
triclinic system
X-ray diffraction data
X-ray photoelectron spectra