Publication
Title
Partitioning of humic acids between aqueous solution and hydrogel : concentration profiling of humic acids in hydrogel phases
Author
Abstract
The partitioning of the natural polyelectrolyte humic acid (HA) from an aqueous dispersion into a model biomimetic gel (alginate) and a synthetic polyacrylamide gel (PAAm) is explored. In both gels, the spatial distribution of HA in the gel body, as measured by confocal laser scanning microscopy, is markedly nonhomogeneous. A striking feature is the enhanced accumulation of HA in a thin film of thickness ca. 15 mu m at the surface of the gel body, resulting in average local concentrations that are, for PAAm and alginate respectively, a factor of 10 and 4 greater than that in the bulk solution. The time dependence of accumulation in the surface film is predominantly controlled by the diffusive supply of HA from the aqueous medium, with a time constant on the order of 10(3) s for both gels. The concentration of HA within the bulk gel body differs significantly from that in the bulk aqueous medium: substantially higher for PAAm but much lower for alginate. The results are significant for understanding the nature and rate of sink/source functioning at permeable phases in contact with aqueous media, e.g., biofilms and gel-like layers at biological interfaces or employed in chemical speciation sensors.
Language
English
Source (journal)
Langmuir: the ACS journal of surfaces and colloids. - Washington, D.C.
Publication
Washington, D.C. : 2014
ISSN
0743-7463
DOI
10.1021/LA4050094
Volume/pages
30 :8 (2014) , p. 2084-2092
ISI
000332494000021
Full text (Publisher's DOI)
UAntwerpen
Publication type
Subject
External links
Web of Science
Record
Identifier
Creation 12.01.2017
Last edited 01.02.2023
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