TY - JOUR
T1 - Identifcation and characterization of nanosized tripuhyite in soil near Sb mine tailings
AU - Mitsunobu, Satoshi
AU - Takahashi, Yoshio
AU - Utsunomiya, Satoshi
AU - Marcus, Matthew A.
AU - Terada, Yasuko
AU - Iwamura, Takeru
AU - Sakata, Masahiro
PY - 2011/7
Y1 - 2011/7
N2 - In soil near tailings from an antimony (Sb) mine, we found micro-grains coated with an antimonyrich layer. These grains were characterized in detail using multiple advanced analytical techniques such as micro-X-ray absorption near edge structure (μ-XANES), micro-extended X-ray absorption fine structure (μ-EXAFS), micro-X-ray diffraction (μ-XRD), transmission electron microscope (TEM), and electron probe microanalysis (EPMA). The EPMA showed that one soil grain (grain A) locally accumulated a large amount of Sb in the secondary phases (40-61 wt% Sb2O5) with significant Fe (20-28 wt% Fe2O3). The spatial distribution of Sb in the grain was similar to that of iron. Both Fe μ-XANES and μ-XRD of the Sb hot spots in grain A consistently showed that the secondary products were dominantly composed of ferric antimonate, tripuhyite (FeSbO4). Fits to the Sb K-edge μ-EXAFS of this phase showed second-neighbor coordination numbers ∼30% smaller than in bulk tripuhyite, indicating that the tripuhyite included in grain A is nanoparticulate and/or has a high structural disorder. The TEM analysis suggests that the particle size of tripuhyite in grain A was around 10 nm, which is consistent with the size range indicated by μ-XRD and μ-EXAFS. This is the first report showing tripuhyite with nanocrystallinity in natural soil to date.
AB - In soil near tailings from an antimony (Sb) mine, we found micro-grains coated with an antimonyrich layer. These grains were characterized in detail using multiple advanced analytical techniques such as micro-X-ray absorption near edge structure (μ-XANES), micro-extended X-ray absorption fine structure (μ-EXAFS), micro-X-ray diffraction (μ-XRD), transmission electron microscope (TEM), and electron probe microanalysis (EPMA). The EPMA showed that one soil grain (grain A) locally accumulated a large amount of Sb in the secondary phases (40-61 wt% Sb2O5) with significant Fe (20-28 wt% Fe2O3). The spatial distribution of Sb in the grain was similar to that of iron. Both Fe μ-XANES and μ-XRD of the Sb hot spots in grain A consistently showed that the secondary products were dominantly composed of ferric antimonate, tripuhyite (FeSbO4). Fits to the Sb K-edge μ-EXAFS of this phase showed second-neighbor coordination numbers ∼30% smaller than in bulk tripuhyite, indicating that the tripuhyite included in grain A is nanoparticulate and/or has a high structural disorder. The TEM analysis suggests that the particle size of tripuhyite in grain A was around 10 nm, which is consistent with the size range indicated by μ-XRD and μ-EXAFS. This is the first report showing tripuhyite with nanocrystallinity in natural soil to date.
UR - http://www.scopus.com/inward/record.url?scp=79960488736&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=79960488736&partnerID=8YFLogxK
U2 - 10.2138/am.2011.3651
DO - 10.2138/am.2011.3651
M3 - Article
AN - SCOPUS:79960488736
SN - 0003-004X
VL - 96
SP - 1171
EP - 1181
JO - American Mineralogist
JF - American Mineralogist
IS - 7
ER -