Preferential Sorption of Tannins at Aluminum Oxide Affects the Electron Exchange Capacities of Dissolved and Sorbed Humic Acid Fractions

2020 ◽  
Vol 54 (3) ◽  
pp. 1837-1847 ◽  
Author(s):  
Edisson Subdiaga ◽  
Mourad Harir ◽  
Silvia Orsetti ◽  
Norbert Hertkorn ◽  
Philippe Schmitt-Kopplin ◽  
...  
Keyword(s):  
Humic Acid ◽  
Aluminum Oxide ◽  
Electron Exchange ◽  
Preferential Sorption

Analysis of soil organic matter at the solid–water interface by nuclear magnetic resonance spectroscopy

2014 ◽  
Vol 11 (4) ◽  
pp. 472 ◽  
Author(s):  
Stephanie C. Genest ◽  
Myrna J. Simpson ◽  
André J. Simpson ◽  
Ronald Soong ◽  
David J. McNally
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Organic Matter ◽  
Humic Acid ◽  
Solid State ◽  
Nmr Spectroscopy ◽  
Magnetic Resonance ◽  
Soil Water ◽  
Mas Nmr ◽  
Water Interface ◽  
Preferential Sorption

Environmental context Structural and conformational information on organic matter–clay complexes and whole soils was obtained using different NMR methods. The results show that organic matter interactions with clay mineral surfaces determine the accessibility of specific organic matter components at the soil–water interface. This physical conformation may also play a role in soil biogeochemical processes and binding to pollutants in terrestrial environments. Abstract Organic matter (OM)–mineral interactions play an important role in OM preservation, global carbon cycling and contaminant transport. Studies have indicated that preferential sorption of OM is dependent on mineral type and solution conditions. In this study, 1H high resolution–magic angle spinning nuclear magnetic resonance (HR-MAS NMR) spectroscopy was employed to examine OM chemistry in organo-clay complexes. Dissolved OM from a forest soil, Leonardite humic acid and Peat humic acid were sorbed to Ca2+ enriched kaolinite and montmorillonite. As observed using 1H HR-MAS NMR spectroscopy, kaolinite sorbed mainly long-chain aliphatic compounds such as those from plant cuticles whereas montmorillonite sorbed a mixture of aliphatic components and proteins. These results show the preferential sorption of specific dissolved OM components on clay surfaces. This was tested further using solid-state 13C and 1H HR-MAS NMR analysis of whole soils containing kaolinite and montmorillonite as well as a Peat soil for contrast. The species present at the soil–water interface were mainly aliphatic components, carbohydrates and amino acids. Aromatic constituents were present in the soils (observed by solid-state 13C NMR and by 1H HR-MAS NMR spectroscopy when a more penetrating solvent was used) which signifies that these compounds likely exist in more hydrophobic domains that are buried and surface inaccessible. This study highlights the important role of OM interactions with clay minerals in the preservation of OM in soils and suggests that OM–OM associations may also play a role in the protection of specific OM components in soil.

Characterization of dissolved organic matter (DOM) extracted from soils by hot water percolation (HWP)

2010 ◽  
Vol 59 (1) ◽  
pp. 99-108 ◽  
Author(s):  
M. Takács ◽  
Gy. Füleky
Keyword(s):  
Organic Matter ◽  
Humic Acid ◽  
Natural Organic Matter ◽  
Extraction Methods ◽  
Soil Samples ◽  
Hot Water ◽  
Soil Extracts ◽  
Water Percolation ◽  
Soil Humic Acid

The Hot Water Percolation (HWP) technique for preparing soil extracts has several advantages: it is easily carried out, fast, and several parameters can be measured from the same solution. The object of this study was to examine the possible use of HWP extracts for the characterization of soil organic matter. The HPLC-SEC chromatograms, UV-VIS and fluorescence properties of the HWP extracts were studied and the results were compared with those of the International Humic Substances Society (IHSS) Soil Humic Acid (HA), IHSS Soil Fulvic Acid (FA) and IHSS Suwannee Natural Organic Matter (NOM) standards as well as their HA counterparts isolated by traditional extraction methods from the original soil samples. The DOM of the HWP solution is probably a mixture of organic materials, which have some characteristics similar to the Soil FA fractions and NOM. The HWP extracted organic material can be studied and characterized using simple techniques, like UV-VIS and fluorescence spectroscopy.

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