Direct Speciation of Phosphorus in Alum-Amended Poultry Litter: Solid-State 31P NMR Investigation

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• 作者：Stefan Hunger ; Herman Cho ; James T. Sims ; and Donald L. Sparks
• 刊名：Environmental Science & Technology
• 出版年：2004
• 出版时间：February 1, 2004
• 年：2004
• 卷：38
• 期：3
• 页码：674 - 681
• 全文大小：138K
• 年卷期：v.38,no.3(February 1, 2004)
• ISSN：1520-5851

文摘

Amending poultry litter (PL) with aluminum sulfate (alum)has proven to be effective in reducing water-solublephosphorus (P) in the litter and in runoff from fields thathave received PL applications; it has therefore been suggestedas a best management practice. Although its effectivenesshas been demonstrated on a macroscopic scale in thefield, little is known about P speciation in either alum-amended or unamended litter. This knowledge is importantfor the evaluation of the long-term stability and bioavailabilityof P, which is a necessary prerequisite for the assessmentof the sustainability of intensive poultry operations. Both solid-state MAS and CP-MAS ³¹P NMR as well as ³¹P{²⁷Al}TRAPDOR were used to investigate P speciation in alum-amended and unamended PL. The results indicate thepresence of a complex mixture of organic and inorganicorthophosphate phases. A calcium phosphate phase, probablya surface precipitate on calcium carbonate, could beidentified in both unamended and alum-amended PL, aswell as physically bound HPO₄^2-. Phosphate associated withAl was found in the alum-amended PL, most probably amixture of a poorly ordered wavellite and phosphate surfacecomplexes on aluminum hydroxide that had been formedby the hydrolysis of alum. However, a complex mixture oforganic and inorganic phosphate species could not beresolved. Phosphate associated with Al comprised on average40 ± 14% of the total P in alum-amended PL, whereascalcium phosphate phases comprised on average 7 ± 4%in the alum-amended PL and 14 ± 5% in the unamendedPL.