Characterization of Phosphorus Species in Biosolids and Manures Using XANES Spectroscopy

Abstract

Identification of the chemical P species in biosolids or manures will improve our understanding of the long-term potential for P loss when these materials are land applied. The objectives of this study were to determine the P species in dairy manures, poultry litters, and biosolids using X-ray absorption near-edge structure (XANES) spectroscopy and to determine if chemical fractionation techniques can provide useful information when interpreted based on the results of more definitive P speciation studies. Our XANES fitting results indicated that the predominant forms of P in organic P sources included hydroxylapatite, PO(4) sorbed to Al hydroxides, and phytic acid in lime-stabilized biosolids and manures; hydroxylapatite, PO(4) sorbed on ferrihydrite, and phytic acid in lime- and Fe-treated biosolids; and PO(4) sorbed on ferrihydrite, hydroxylapatite, beta-tricalcium phosphate (beta-TCP), and often PO(4) sorbed to Al hydroxides in Fe-treated and digested biosolids. Strong relationships existed between the proportions of XANES PO(4) sorbed to Al hydroxides and NH(4)Cl- + NH(4)F-extractable P, XANES PO(4) sorbed to ferrihydrite + phytic acid and NaOH-extractable P, and XANES hydroxylapatite + beta-TCP and dithionite-citrate-bicarbonate (DCB)- + H(2)SO(4)-extractable P (r(2) = 0.67 [P = 0.01], 0.78 [P = 0.01], and 0.89 [P = 0.001], respectively). Our XANES fitting results can be used to make predictions about long-term solubility of P when biosolids and manures are land applied. Fractionation techniques indicate that there are differences in the forms of P in these materials but should be interpreted based on P speciation data obtained using more advanced analytical tools.

Organic phosphorus in the aquatic environment

“…[8] This is notwithstanding the fact that the most common colourimetric assay used for filterable reactive P quantification (the molybdenum blue technique) may also hydrolyse several known organic compounds [9] (although this has been questioned). [10] At the other end of the spectrum researchers have used several sophisticated (and expensive) instruments to explore organic P speciation including ultra-high field mass spectrometry, [11] X-ray absorption near edge structure (XANES) spectroscopy [12,13] (which requires a source of synchrotron radiation), and solution and solid state 31 P NMR spectroscopy. [14] Of these more sophisticated approaches, based on the number of publications, solution 31 P NMR spectroscopy appears to have been the most influential.…”

Characterization of refractory organic substances by NEXAFS using a compact X-ray source

“…2 and the inset. Secondly, we took advantage of the fact that published NEXAFS-spectra of many chemical compounds already exist, e.g., (Smith et al 2001;Hitchcock et al 2005;Dhez et al 2003;Shober et al 2006;Hitchcock 2009;Ishii and Hitchcock 1988;Cooney and Urquhart 2004;Solomon et al 2005Solomon et al , 2009. We compared these with the positions gained from the derivatives.…”

Synchrotron‐Based Near‐Edge X‐Ray Spectroscopy of Natural Organic Matter in Soils and Sediments

“…However, note that in the N-NEXAFS spectra shown in Figure 17.7 a small peak at 399.1 eV is due to the presence of aromatic nitrogen. Phosphorus NEXAFS has been used primarily to examine organic phosphorus in amended soils and animal manure (Peak et al, 2002;Beauchemin et al, 2003;Shober et al, 2006). The high phosphorus content of these samples allowed for the use of NEXAFS techniques, but phosphorus typically exists in very low concentrations within natural soils and sediments.…”