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Chemical Species of Phosphorus and Zinc in Water‐Dispersible Colloids from Swine Manure Compost
Author(s) -
Yamamoto Kosuke,
Hashimoto Yohey
Publication year - 2017
Publication title -
journal of environmental quality
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.888
H-Index - 171
eISSN - 1537-2537
pISSN - 0047-2425
DOI - 10.2134/jeq2016.11.0433
Subject(s) - compost , zinc , chemistry , manure , phosphorus , ferrihydrite , phosphate , struvite , environmental chemistry , agronomy , adsorption , organic chemistry , biology
The release of phosphorus (P) and zinc (Zn) from swine manure compost and from soils applied with swine manure compost can be accelerated by colloidal particles. This study investigated the concentrations and chemical species of P and Zn in water‐dispersible colloids (WDCs) collected from swine manure compost by using X‐ray absorption fine structure (XAFS) spectroscopy. A filtration and ultracentrifugation process was used to separate and collect WDCs (20–1000 nm) from the bulk swine manure compost (<2 mm). The swine manure compost contained 2.7 g kg −1 WDC, in which P (140 g kg −1 ) was highly concentrated and Zn concentrations were greater than in the bulk compost (1.45 g kg −1 ). Phosphorus K‐edge X‐ray absorption near‐edge structure (XANES) spectroscopy determined the presence of struvite (NH 4 MgPO 4 ·6H 2 O) as a major P species (74%), followed by tricalcium phosphate as a secondary component (26%). In the WDC fraction, struvite was not found, but tricalcium phosphate (56%) occurred as a primary component. Zinc K‐edge XAFS spectroscopy determined hopeite [Zn 3 (PO 4 ) 2 ·4H 2 O, 59%] and to a lesser extent smithsonite (ZnCO 3 , 24%) and Zn adsorbed on ferrihydrite (17%). In the WDC fraction, hopeite (44%) and organically bound Zn (35%) were predominant. Our results demonstrate the notable difference in the concentration and chemical species of P and Zn between the WDC and bulk fractions of swine manure compost. Core Ideas We investigated chemical species of P and Zn in the WDC collected from swine manure compost. Struvite was not found in WDC, but tricalcium phosphate and P adsorbed on ferrihydrite were predominant. Hopeite and organically bound Zn were predominant in the WDC fraction.