Studies of the nature of binding sites of first row transition elements bound to aquatic and soil humic substances using X-ray absorption spectroscopy

Xia, Kang; Bleam, William F.; Helmke, P. A.

doi:10.1016/s0016-7037(97)00080-x

Cited by 115 publications

(72 citation statements)

References 59 publications

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“…Scattering from the C atom might not be visible because the backscatter amplitude of a carbon atom becomes weak steeply with increasing wavenumber (k) and is smaller than those of the O atom and the Cr atom. An earlier report described that Co, Ni, Cu, and Zn form the inner sphere complex with humic and fulvic acids (Xia et al, 1997). The IR spectra of Cr-HA complexes indicate the presence of Cr-carboxylate binding (Fukushima et al, 1995).…”

Section: Structural Model Of Cr Binding With Hamentioning

confidence: 85%

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Speciation study of Cr(VI/III) reacting with humic substances and determination of local structure of Cr binding humic substances using XAFS spectroscopy

et al. 2012

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Section: Structural Model Of Cr Binding With Hamentioning

confidence: 85%

“…4 and Table 2). Xia et al (1997) reported that Co, Ni, Cu, and Zn form the inner sphere complex with the carboxyl group of humic and fulvic acids. They reported the presence of the second shell representing scattering from the C atom in the EXAFS spectra.…”

Section: Structural Analysis Of Cr Reacting With Ha Using Exafs Spectramentioning

confidence: 99%

Speciation study of Cr(VI/III) reacting with humic substances and determination of local structure of Cr binding humic substances using XAFS spectroscopy

et al. 2012

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“…3 k 2 -weighted Pb L III EXAFS spectra of soil and the mineral phase samples saturated by Pb(NO 3 ) 2 (a) and Fouriertransformed k 2 -weighted Pb L III EXAFS spectra for soil sample and the mineral phase samples (b) form different complexes depending on the ionic strength. Lead mainly forms outer-sphere complexes on the basal plane of the phyllosilicate minerals or in the intersheet layer under low ionic strength and inner-sphere complexes at the edges of the mineral under high ionic strength (Xia et al 1997).…”

Section: Resultsmentioning

confidence: 99%

“…Numerous current studies deal with the adsorption mechanisms of heavy metals by different soil components, including organic matter, clay minerals, Fe and Mn (hydr)oxides, etc. because some inorganic and organic phases of soil have high buffering capacity for a wide range of soil pollutants and thus ensure the protective function of the soil (Alcacio et al 2001;Dähn et al 2001;Elzinga et al 2006;Furnare et al 2005;Manceau and Matynia 2010;Minkina et al 2013;Rouff et al 2005;Strawn and Baker 2008;Xia et al 1997).…”

Section: Introductionmentioning

confidence: 99%

Comprehensive study of Pb (II) speciation in soil by X-ray absorption spectroscopy (XANES and EXAFS) and sequential fractionation

et al. 2015

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Purpose The study is aimed at the analysis of the spatialstructural organization of Pb(II) in Chernozem soils and the relationship between the metal ion and the soil components using X-ray absorption spectroscopy and chemical extractive fractionation. Materials and methods In a model experiment, soil samples were artificially contaminated with elevated rates of Pb(NO 3 ) 2 and PbO (2000 and 10,000 mg kg −1 ). The samples of mineral phases (bentonite, gibbsite, kaolinite, calcite, and hydromuscovite) were saturated with Pb 2+ ions. The sequential fractionation of Pb in the soil was conducted by the Tessier method. X-ray absorption near-edge fine structure (XANES) spectra at the Pb L III -edge (13.040 keV) were obtained on a Rigaku R-XAS Looper spectrometer. Extended X-ray absorption fine structure (EXAFS) L III -edge Pb was measured at the Structural Materials Science beamline of the Kurchatov Center for Synchrotron Radiation. Results and discussion The results of successive extraction showed that Pb is associated with strongly bound organic substances, Fe and Mn (hydr)oxides, and carbonates. An increase in the portion of exchangeable fraction is observed under extreme loads. At the addition of Pb in the form of oxide and nitrate to the soil, the fractional compositions were similar, which indicates the good transformation of PbO in Chernozem. The features of XANES spectra indicate different orbital transitions in the electron shells of Pb 2+ ions for monoxide (PbO) and soluble salt (Pb(NO 3 ) 2 ), which affect the ion properties and determine the individual structure of the coordination sphere. The analysis of XANES revealed that sorption of Pb in the soil samples and in the samples of mineral phases does not change its bond valence. Conclusions The increased degree of soil contamination with Pb is accompanied by decreasing the stable connection between metal and soil components. Lead ions in bentonite, kaolinite, hydromuscovite, gibbsite, and calcite are incorporated in the positions of the inner-sphere complex replacing some aluminum ions in the octahedral sites. This results in changes the Pb-O distances in Pb-bearing octahedrons. We may suggest that Pb 2+ is also sorbed by dimer (Pb-Pb) silicate and/or aluminum groups. The structure of adsorbent surface plays the key role in the sorption of Pb 2+ by mineral phases.

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“…, pyrolysis-mass spectrometry (van Loon et al, 1993;Saiz-Jimenez et al, 1993;Schulten, 1996;Sihombing et al, 1996;Peuravuori and Pihlaja, 1997c), X-ray absorption spectroscopy (Xia et al, 1997), XANES and EXAFS (Davies et al, 1997;Morra et al, 1997).…”

Section: Speciation In Freshwaters 203mentioning

confidence: 99%

Speciation in Freshwaters

Filella¹,

Town²,

Buffle³

2002

Chemical Speciation in the Environment

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Studies of the nature of binding sites of first row transition elements bound to aquatic and soil humic substances using X-ray absorption spectroscopy

Cited by 115 publications

References 59 publications

Speciation study of Cr(VI/III) reacting with humic substances and determination of local structure of Cr binding humic substances using XAFS spectroscopy

Speciation study of Cr(VI/III) reacting with humic substances and determination of local structure of Cr binding humic substances using XAFS spectroscopy

Comprehensive study of Pb (II) speciation in soil by X-ray absorption spectroscopy (XANES and EXAFS) and sequential fractionation

Speciation in Freshwaters

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