Experimental Validation of Quantitative XANES Analysis for Phosphorus Speciation

Ajiboye, Babasola; Akinremi, O. O.; Jürgensen, Astrid

doi:10.2136/sssaj2007.0007

Cited by 63 publications

(59 citation statements)

References 12 publications

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“…This supposition has been explicitly verified for some phosphorus compounds by empirical experiments (32). However, when working with environmental samples, it is still an assumption that standards are representative for the actual P-species in the sample.…”

Section: Discussionmentioning

confidence: 89%

XANES Speciation of P in Environmental Samples: An Assessment of Filter Media for on-Site Wastewater Treatment

Eveborn

Gustafsson

Hesterberg

et al. 2009

Environ. Sci. Technol.

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X-ray absorption near edge structure (XANES) is a useful technique for characterisation of chemical species of phosphorus in complex environmental samples. To develop and evaluate 1 bed filters as sustainable on-site wastewater treatment solutions, our objective in this study was to determine the chemical forms of accumulated phosphorus in a selection of promising filter materials: Filtralite P, Filtra P, Polonite, Absol, blast furnace slag, and wollastonite.Full-scale operational wastewater-treatment systems were sampled and in addition, filter samples collected from laboratory studies provided access to additional media and complementary samples. Phosphorus species were characterized using phosphorus K-edge XANES spectroscopy, complemented by X-ray powder diffraction (XRPD) and attenuated total reflectance Fourier-transform infrared spectroscopy (ATR-FTIR). No systematic differences could be seen in the results between laboratory-and full-scale samples. All six filter media contained significant amounts of crystalline calcium phosphates. Some samples also contained amorphous calcium phosphate (>60% of total P in Absol). In Filtralite P and blast furnace slag, more than 35% of the accumulated phosphorus was associated with Fe or Al. Both the power and shortcomings of XANES analysis for characterizing P species in these filter media are discussed.

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Section: Discussionmentioning

confidence: 89%

XANES Speciation of P in Environmental Samples: An Assessment of Filter Media for on-Site Wastewater Treatment

Eveborn

Gustafsson

Hesterberg

et al. 2009

Environ. Sci. Technol.

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“…Kaolinite normalization (Ajiboye et al, 2007(Ajiboye et al, , 2008. Therefore, the real uncertainty of an LCF is larger, as shown by studies in which the P speciation of welldefined mixtures was calculated by LCF (Ajiboye et al, 2007;Werner and Prietzel, 2015).…”

Section: Depthmentioning

confidence: 99%

“…Therefore, the real uncertainty of an LCF is larger, as shown by studies in which the P speciation of welldefined mixtures was calculated by LCF (Ajiboye et al, 2007;Werner and Prietzel, 2015). However, consideration of normalization errors is difficult for samples with unknown composition.…”

Section: Depthmentioning

confidence: 99%

Evolution of phosphorus speciation with depth in an agricultural soil profile

et al. 2016

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Available online xxxxWith time, different soil-forming processes such as weathering, plant growth, accumulation of organic matter, and cultivation are likely to affect phosphorus (P) speciation. In this study, the depth distribution of P species was investigated for an agricultural clay soil, Lanna, Sweden. Small amounts of apatite-P was demonstrated in the topsoil whereas the speciation of P at 70-100 cm depth consisted of approximately 86% apatite according to P K-edge XANES (X-ray absorption near-edge structure) spectroscopy. Because there were only minor differences in bulk mineralogy and texture, these variations in P speciation were interpreted as the result of apatite weathering of the topsoil. Speciation modeling on soil extracts supported this idea: hydroxyapatite was not thermodynamically stable in the top 50 cm of the soil. Apatite was enriched in the bulk soil relative to the clay fraction, as expected during apatite dissolution. Combined results from batch experiments, XANES spectroscopy and X-ray diffraction suggested chemical transformations of the topsoil as a result from accumulation of organic matter and airing from tillage followed by enhanced weathering of apatite, amphiboles, clay minerals, and iron oxides. This caused the formation of poorly crystalline secondary iron and aluminum (hydr)oxides in the topsoil, which retained part of the released P from apatite. Other P was incorporated into organic forms. Furthermore, the results also showed that short-term acidification below the current pH value (below 5.5 in the topsoil and 7.2 in the deeper subsoil) caused significant solubilization of P. This is attributed to two different mechanisms: the instability of Al-containing sorbents (e.g. Al hydroxides) at low pH (in the topsoil), and the acid-mediated dissolution of apatite (the subsoil).

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“…Athena was used to fit the near-edge region of the XAS spectra as a linear combination of reference spectra with typical relative errors on the order of 5%-10%. Recent work suggests that material preparation can affect this error [54,55]. The XANES reference spectra were collected from both TcO 2 and TcO 4 − standards prepared previously reported [17,68].…”

Section: Analysesmentioning

confidence: 99%