Studies of Cu(II) in soil by X-ray absorption spectroscopy

Frenkel, Anatoly I.; Korshin, Gregory V.

doi:10.4141/s00-073

Cited by 15 publications

(15 citation statements)

References 15 publications

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“…This is in accordance with the results of X-ray absorption analyses by other studies (e.g. Frenkel and Korshin, 2001;Lewis et al, 2011), which showed that both Pb and Cu are bound predominantly by oxygen-containing functional groups in soils, which may be associated both with organic (humic-like) and inorganic metal-oxide (e.g. Pb-and Cu-oxides) or even silicate phases.…”

Section: Iron Fractionation As Related To That Of the Trace Metalssupporting

confidence: 93%

Relationship between iron and trace metal fractionation in soils

Sipos

Choi

Németh

et al. 2014

Chemical Speciation & Bioavailability

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Iron compounds significantly affect the behaviour of trace elements in soils. Sequential chemical extractions are widely used to estimate not only the solid phase speciation of chemical elements but to study their mobilisation conditions. In this paper, we present results about the effect of iron fractionation on that of trace metals (Co, Cr, Cu, Ni, Pb and Zn) in representative soils for Hungary. Our aim was to study the effect of pedogenic processes and soil parent material on trace metal association with soil iron phases. Two major soil groups, such as Luvisols and non-Luvisols could be established based on trace metal content, distribution and fractionation in the studied soils. Such differences were found to be primarily due to the differences in the pedogenic processes in the studied soils, whereas soil parent material has not affected these characteristics significantly. We found that Fe phases affect trace metal fractionation and mobilisation as their host in form of both inherited and pedogenic phases. However, pedogenic processes, primarily iron and organic matter accumulation in our case, generally overwrite the effect of inherited iron phases on trace metal accumulation, distribution and fractionation. Among the studied metals, fractionation of Co and Cr were found to be much more affected by that of Fe, followed by Cu, Zn and Ni, whereas Pb could be associated with iron phases only subordinately.

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Section: Iron Fractionation As Related To That Of the Trace Metalssupporting

confidence: 93%

Relationship between iron and trace metal fractionation in soils

Sipos

Choi

Németh

et al. 2014

Chemical Speciation & Bioavailability

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“…The EXAFS data analysis of the CuPd/PVPy sample revealed the presence of two Cu–O coordination shells consistent with Cu 2+ ions coordinated with O atoms at short (1.94 Å) and longer (2.52 Å) distances and a Cu–Pd contribution exhibiting a distance and coordination number compatible with the results obtained at the Pd K‐edge . The two different Cu–O distances found were also confirmed by the presence of the two peaks (labelled C and D) between 8981 eV and 8993 eV in the first derivative of the XANES spectrum of the CuPd sample (Figure ) that are normally associated to a tetragonal distortion of the CuO 6 octahedron that gives shorter equatorial and longer axial Cu−O bonds. In the absence of a tetragonal distortion, the splitting observed in Figure disappears.…”

Section: Resultssupporting

confidence: 72%

Characterization of a Poly‐4‐Vinylpyridine‐Supported CuPd Bimetallic Catalyst for Sonogashira Coupling Reactions

et al. 2017

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CuPd bimetallic solvated metal atoms (SMA) synthesized by metal vapor synthesis (MVS) technique and supported on poly-4-vinylpyridine (PVPy) resin, showed significantly higher catalytic activity in Sonogashira-type carbon-carbon coupling reactions than the corresponding monometallic Cu and Pd systems as well as their physical mixture. The analysis of the bimetallic catalyst combining transmission electron microscopy techniques and X-ray absorption fine structure (XAFS) spectroscopy revealed the presence of small Pd nanoparticles (d =2.5 nm) while the analysis of the X-ray absorption data, at the Cu K-edge suggests the formation of thin and incomplete Cu oxide layers around the Pd-rich cores.

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“…5b) indicates that the axial ligand(s) are located at about 1.9 + 0.4 Å or 2.3 Å (Frenkel et al, 2000). We cannot confirm whether Cu has one or two axial ligands but, in principle, both outcomes are reasonable because Cu in aqueous solution prefers a 5-fold elongated square pyramidal coordination that is likely to be competitive with a 6-fold distorted octahedral coordination (Frenkel and Korshin, 2001;Bryantsev et al, 2008).…”

Section: Shell-by-shell Fits Of Exafs Spectramentioning

confidence: 80%

Copper sorption by the edge surfaces of synthetic birnessite nanoparticles

2015

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a b s t r a c tWe investigated the sorption of Cu by δ-MnO 2 , an analog for natural birnessite (layer-type Mn oxide) that is characterized by randomly stacked and curled nanosheets, a low to moderate vacancy content, and variable amounts of layer and interlayer Mn 3+ . The synthetic δ-MnO 2 used in this study had a Na:Mn molar ratio of 0.13, an average manganese oxidation number (AMON) of 3.85 after reaction, a specific surface area of 254 m 2 g −1 and a particle size of 2-4 nm in the ab plane. The maximum surface excess (q max ) value at pH 6 estimated from sorption data of 0.72 (0.64-0.83, 95% confidence interval) mol Cu mol −1 Mn far exceeded the nominal vacancy content for δ-MnO 2 (ca. 6-11% mol vacancy mol −1 Mn), thus implicating multiple binding sites for Cu. The large values of q max and specific surface area of the mineral suggest a major role for surface sites at the particle edges relative to vacancy sites. The extended X-ray absorption fine structure (EXAFS) spectra from δ-MnO 2 samples differ with respect to the EXAFS spectra for Cu(OH) 2 , CuO, and Cu 3 (CO 3 ) 2 (OH) 2 and Cu-sorbed by biogenic MnO 2 . The Cu K-edge EXAFS spectra show two second-shell peaks that can be modeled with Mn and Cu nearneighbors. Copper appears to bind dominantly at particle edges of δ-MnO 2 as dimers or polynuclear surface species. This sorption mechanism is consistent with the moderate vacancy content of δ-MnO 2 and explains the similarity in the EXAFS spectra from samples having surface loadings of 0.01 to 0.26 mol Cu mol −1 Mn. The strong proclivity of Cu to bind on the edge surfaces of nanoparticulate birnessite leads to very large surface excesses of Cu without the formation of a discreet precipitate, making the surface sites at the particle edges the dominant sorption site for Cu.

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Studies of Cu(II) in soil by X-ray absorption spectroscopy

Cited by 15 publications

References 15 publications

Relationship between iron and trace metal fractionation in soils

Relationship between iron and trace metal fractionation in soils

Characterization of a Poly‐4‐Vinylpyridine‐Supported CuPd Bimetallic Catalyst for Sonogashira Coupling Reactions

Copper sorption by the edge surfaces of synthetic birnessite nanoparticles

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