<abstract xmlns="http://www.w3.org/1999/xhtml"><p>Humic substances are able to reduce the surface tension of their solutions and thus can act as surface-active substances in the natural environment, which may have industrial application. The ability to influence the surface tension of humic acid solutions depends on the origin of the humic acids. The objective of this study was comparison of the ability of humic acids of different origin (soil, water, peat, lignite etc.) to influence the surface tension of their solutions, and identification of the structural characteristics of peat humic acids that determine their surfactant properties. Industrially produced humic materials demonstrated no or insignificant impact on the surface tension of their solutions. However, humic acids isolated from peat had significant impact of the surface tension of their solutions, acting as weak surfactants. The surface tension of humic acid solutions decreased with increasing concentration, and depended on solution pH. Using a well-characterised bog profile, the ability to influence the surface tension of peat humic acids was shown to depend on age and humification degree. With increase of the humification degree and age, molecular complexity of humic acids and their ability to influence surface tension decreased; but nevertheless, the impact of the biological precursor (peat-forming bryophytes and plants) could be identified.</p></abstract>

Humic substances are able to reduce the surface tension of their solutions and thus can act as surface-active substances in the natural environment, which may have industrial application. The ability to influence the surface tension of humic acid solutions depends on the origin of the humic acids. The objective of this study was comparison of the ability of humic acids of different origin (soil, water, peat, lignite etc.) to influence the surface tension of their solutions, and identification of the structural characteristics of peat humic acids that determine their surfactant properties. Industrially produced humic materials demonstrated no or insignificant impact on the surface tension of their solutions. However, humic acids isolated from peat had significant impact of the surface tension of their solutions, acting as weak surfactants. The surface tension of humic acid solutions decreased with increasing concentration, and depended on solution pH. Using a well-characterised bog profile, the ability to influence the surface tension of peat humic acids was shown to depend on age and humification degree. With increase of the humification degree and age, molecular complexity of humic acids and their ability to influence surface tension decreased; but nevertheless, the impact of the biological precursor (peat-forming bryophytes and plants) could be identified.

Surface Activity of Humic Acids Depending on Their Origin and Humification Degree

Department of Environmental Science, University of Latvia, Raina bulv. 19, Rīga, LV-1586, LATVIA

Proceedings of the Latvian Academy of Sciences. Section B. Natural, Exact, and Applied Sciences.

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

HUMUSVIELU IZCELSMES UN HUMIFIKĀCIJAS PAKĀPES IETEKME UZ TO VIRSMAS AKTIVITĀTI

Humic substances are able to reduce the surface tension of their solutions and thus can act as surface-active substances in the natural environment, which may...

Surface Activity of Humic Acids Depending on Their Origin and Humification Degree

Published Online: Jul 17, 2014

Page range: 493 - 499

Received: Jan 18, 2013

DOI: https://doi.org/10.2478/prolas-2013-0083

Keywords
surface tension, humic acids, humification degree, peat

© 2013 Māris Klaviņš and Oskars Purmalis

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

Surface Activity of Humic Acids Depending on Their Origin and Humification Degree

Published Online: Jul 17, 2014

Page range: 493 - 499

Received: Jan 18, 2013

DOI: https://doi.org/10.2478/prolas-2013-0083

Keywordssurface tension, humic acids, humification degree, peat

© 2013 Māris Klaviņš and Oskars Purmalis

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

Keywords
surface tension, humic acids, humification degree, peat