Univ. of Rostock, Institute for Land Use, Justus-von-Liebig Weg 6, D-18051 Rostock, Germany.
J Environ Qual. 2010 Nov-Dec;39(6):2179-84. doi: 10.2134/jeq2010.0114.
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 L2.3-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-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.
农业工业副产物中的磷（P）——一种潜在的淡水富营养化源，但也是一种有价值的肥料——需要进行形态分析，以评估其在环境中的归宿。我们研究了在多大程度上，X 射线吸收近边结构（XANES）光谱在 P K 和 L2.3 边缘反映了来自埃塞俄比亚糖厂（甘蔗[Saccharum officinarum L.]）和尼日尔种子（Guizotia abyssinica Cass.；NIC）加工行业的顺序提取滤饼（FIC 和 NIC）之间的差异。磷分级提取去除了更易变的（54%）和 H2SO4-P（28%）来自 FIC 比 NIC（18%易变，12% H2SO4-P）。对于每个提取步骤后的 FIC 残渣，P K 边缘光谱的线性组合（LC）拟合提供了证据，证明在 NaOH 提取后 Ca-P 富集，在 H2SO4 处理后几乎完全去除。LC 拟合对于 NIC 样品不成功，可能是因为有机磷化合物占主导地位。FIC（大）和 NIC（小）之间 Ca-P 化合物的不同比例在 L2 边缘比在 K 边缘 XANES 光谱中更为明显。总之，互补的 P K 和 L2.3 边缘 XANES 的附加值得到了明确证明，磷分级提取和形态分析结果共同证明 FIC 和 NIC 可作为热带土壤改良剂。
