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Applied and Environmental Soil Science
Volume 2012 (2012), Article ID 430354, 12 pages
http://dx.doi.org/10.1155/2012/430354
Research Article

The Effect of Dissolved Humic Acids on Aluminosilicate Formation and Associated Carbon Sequestration

1School of Earth and Environmental Sciences, Queens College CUNY, Flushing, NY 11367, USA
2Department of Geosciences, Stony Brook University, Stony Brook, NY 11794, USA
3Department of Earth and Environmental Sciences, University of Illinois at Chicago, Chicago, IL 60607, USA

Received 20 September 2011; Revised 19 November 2011; Accepted 19 November 2011

Academic Editor: Teodoro Miano

Copyright © 2012 Ashaki A. Rouff et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

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 , 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.