Spectroscopic Investigation of Arsenate and Selenate Incorporation into Hydroxylapatite
The mechanism(s) of arsenate and selenate incorporation into hydroxylapatite (HAP) using extended X-ray absorption fine structure (EXAFS) spectroscopy was investigated for As- and Se-doped HAP samples with concentrations between 200 and 2500 ppm. EXAFS data on As and Se K-edges have shown similar local coordination environments and are similar to that of P in HAP, suggesting the substitution of arsenate or selenate tetrahedra on the phosphate sites. EXAFS best-fitting for As-doped samples shows that the first shell is fitted with approximately 4 O atoms at {approx}1.68 {angstrom}, showing As(V) in tetrahedral coordination, and Se K-edge EXAFS data are characterized by the backscattering contributions an oxygen shell at 1.2 {angstrom} in the Fourier transform, which can be fit with 4 O atoms at {approx}1.65 {+-} 0.01 {angstrom}. This is characteristic of Se-O distances in SeO{sub 4} tetrahedron. These findings suggest that arsenate and selenate substitute for phosphate groups with local distortions during the incorporation of these metals into the structure of HAP.
- Research Organization:
- Brookhaven National Laboratory (BNL) National Synchrotron Light Source
- Sponsoring Organization:
- DOE - OFFICE OF SCIENCE
- DOE Contract Number:
- AC02-98CH10886
- OSTI ID:
- 1020161
- Report Number(s):
- BNL--96011-2011-JA
- Journal Information:
- Current Applied Physics, Journal Name: Current Applied Physics Journal Issue: 1 Vol. 10; ISSN 1567-1739
- Country of Publication:
- United States
- Language:
- English
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