Phosphorus speciation in sequentially extracted agro-industrial by-products: Evidence from X-ray absorption near edge structure spectroscopy

Jens Kruse, Wakene Negassa, Narayana Appathurai, Lucia Zuin, Peter Leinweber*

*Corresponding author af dette arbejde

Publikation: Bidrag til tidsskriftTidsskriftartikelForskningpeer review

30 Citationer (Scopus)

Abstract

The phosphorus (P) in agro-industrial by-products - a potential source of freshwater eutrophication but also a valuable fertilizer - needs to be speciated to evaluate its fate in the environment. We investigated to what extent X-ray absorption near edge structure (XANES) spectroscopy at the P K- and L 2,3-edges reflected differences in sequentially extracted filter cakes from sugarcane (Saccharum officinarum L.) (FIC) and niger seed (Guizotia abyssinica Cass.; NIC) processing industry in Ethiopia. The P fractionation removed more labile (54%) and H2SO4-P (28%) from FIC than from NIC (18% labile, 12% H2SO4-P). For the FIC residues after each extraction step, linear combination (LC) fitting of P K-edge spectra provided evidence for the enrichment of Ca-P after the NaOH-extraction and its almost complete removal after the H2SO4-treatment. The LC-fitting was unsuccessful for the NIC samples, likely because of the predominance of organic P compounds. The different proportions of Ca-P compounds between FIC (large) and NIC (small) were more distinctive in L2,3- than in the K-edge XANES spectra. In conclusion, the added value of complementary P K- and L2,3-edge XANES was clearly demonstrated, and the P fractionation and speciation results together justify using FIC and NIC as soil amendments in the tropics.

OriginalsprogEngelsk
TidsskriftJournal of Environmental Quality
Vol/bind39
Udgave nummer6
Sider (fra-til)2179-2184
Antal sider6
ISSN0047-2425
DOI
StatusUdgivet - 2010
Udgivet eksterntJa

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