TY - JOUR
T1 - The effect of dissolved humic acids on aluminosilicate formation and associated carbon sequestration
AU - Rouff, Ashaki A.
AU - Phillips, Brian L.
AU - Cochiara, Stacey G.
AU - Nagy, Kathryn L.
PY - 2012
Y1 - 2012
N2 - Allophane and imogolite neogenesis in soils may occur in the presence of organic matter. To understand this process under conditions relevant to soils, the influence of dissolved organic carbon (DOC) as humic acid (HA), on aluminosilicate formation was studied at 25 C °, pH 6, and low-DOC concentrations. For solutions with initial Al/Si ratios of 1-2.1, and 0-6 mg/L DOC, precipitates recovered after 20 h had Al/Si ratios of 2.2-2.7. The formation of allophane, imogolite-like material, and aluminosilicate gel was confirmed by XRD, FTIR, and NMR. The effect of DOC was to produce a small, but systematic increase in imogolite-like Si in the precipitate, and a decrease in the formation of aluminosilicate gel. Results suggest that the presence of DOC as HA slows the otherwise rapid polymerization of Al and Si at low temperature, and may also promote the formation of imogolite. The high C content of these precipitates indicates that this process may facilitate the sequestration of organic matter, slowing C cycling in soils.
AB - Allophane and imogolite neogenesis in soils may occur in the presence of organic matter. To understand this process under conditions relevant to soils, the influence of dissolved organic carbon (DOC) as humic acid (HA), on aluminosilicate formation was studied at 25 C °, pH 6, and low-DOC concentrations. For solutions with initial Al/Si ratios of 1-2.1, and 0-6 mg/L DOC, precipitates recovered after 20 h had Al/Si ratios of 2.2-2.7. The formation of allophane, imogolite-like material, and aluminosilicate gel was confirmed by XRD, FTIR, and NMR. The effect of DOC was to produce a small, but systematic increase in imogolite-like Si in the precipitate, and a decrease in the formation of aluminosilicate gel. Results suggest that the presence of DOC as HA slows the otherwise rapid polymerization of Al and Si at low temperature, and may also promote the formation of imogolite. The high C content of these precipitates indicates that this process may facilitate the sequestration of organic matter, slowing C cycling in soils.
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U2 - 10.1155/2012/430354
DO - 10.1155/2012/430354
M3 - Article
AN - SCOPUS:84873843534
SN - 1687-7667
VL - 2012
JO - Applied and Environmental Soil Science
JF - Applied and Environmental Soil Science
M1 - 430354
ER -