Composition-Dependent Sorptive Fractionation of Anthropogenic Dissolved Organic Matter by Fe(III)-Montmorillonite

Soils

Bahureksa, William¹  Chen, Huan²  Young, Robert B.³  Avneri-Katz, Shani⁴  McKenna, Amy M.⁵ 

[1] Author to whom correspondence should be addressed;Department of Chemistry, Colorado State University, Fort Collins, CO 80523, USA;Department of Soil and Crop Sciences, Colorado State University, Fort Collins, CO 80523, USA;Department of Soil and Water Sciences, Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot 7610001, Israel;National High Magnetic Field Laboratory, Florida State University, Tallahassee, FL 32310, USA

关键词: soil organic matter;    dissolved organic carbon;    dissolved organic nitrogen;    sorption;    adsorption;    iron;    clay;    sewage sludge;    FT-ICR MS;   

DOI  :  10.3390/soilsystems2010014

学科分类：土壤学

来源: mdpi

【 摘 要 】

Water transports organic matter through soils, where mineral-organic associations form to retain dissolved organic matter (“DOM”), influencing terrestrial carbon cycling, nutrient availability for plant growth, and other soil organic matter functions. We combined Fourier transform ion cyclotron resonance mass spectrometry with novel data analysis techniques to examine the role of sorptive fractionation in the associations between Fe(III)-montmorillonite and DOM from composted biosolids (“anthropogenic DOM”). To examine the influence of DOM composition on sorption and sorptive fractionation, we used resin-based separation to produce DOM subsamples with different molecular compositions and chemical properties. A large proportion (45 to 64%) of the initial carbon in every DOM solution sorbed to the Fe(III)-montmorillonite. However, when the compositions of the initial solutions were compared to the sorbed organic matter, the computed changes in composition were lower (10 to 32%). In fact, non-selective sorption was more important than selective sorption in every sample, except for the hydrophilic neutral (HiN) fraction, where high nitrogen content and acidic conditions appeared to enhance sorptive fractionation. The results from this study demonstrate that the importance of sorptive fractionation varies with DOM composition and other factors, and that non-selective sorption can contribute substantially to the formation of mineral-organic associations.

【 授权许可】

CC BY