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| Titel |
The wettability of selected organic soils in Poland |
| VerfasserIn |
A. Całka, M. Hajnos |
| Konferenz |
EGU General Assembly 2009
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 11 (2009) |
| Datensatznummer |
250022599
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| Zusammenfassung |
| The wettability was measured in the laboratory by means of two methods: Water Drop
Penetration Time (WDPT) test and Thin Column Wicking (TCW) method. WDPT is
fast and simple method and was used to investigate potential water repellency of
analyzed samples. TCW is an indirect method and was used to determine contact
angles and surface free energy components. The measurement was performed in
horizontal teflon chambers for thin-layer chromatography, adapted for tubes 10 cm
long.
The experiment was carried out on muck soils (samples were taken from two levels of soil
profile: 0-20 cm and 20-40 cm) and peat soils. There were two types of peats: low-moor peats
and high moor peats. Samples of low-moor peats were taken from level 25-75 cm (alder peat)
and 75-125cm (sedge peat) and 25-75 cm (peloid peat). Samples of high moor
peats from level 25-175 cm (sphagnum peat) and 175-225 cm (sphagnum peat with
Eriophorum).
There was found no variability in persistence of potential water repellency but there were
differences in values of contact angles of individual soil samples. Both muck and peat
samples are extremely water repellent soils. Water droplets persisted on the surface of soils
for more than 24 hours. Contact angles and surface free energy components for all samples
were differentiated. Ranges of water contact angles for organic soils are from 27,54o to
96,50o. The highest values of contact angles were for sphagnum peats, and the
lowest for muck soil from 20-40 cm level. It means, that there are differences in
wettability between these samples. Muck soil is the best wettable and sphagnum peats is
the worst wettable soil. If the content of organic compounds in the soil exceeds
40% (like in peats), the tested material displays only dispersion-type interactions.
Therefore for peat soils, the technique of thin column wicking could only be used to
determine the dispersive component γiLW. For muck soils it was also determined
electron-acceptor (Lewis acid) γ+ and electron-donor (Lewis base) γ- surface free energy
components.
The authors gratefully acknowledge the Ministry of Science and Higher Education for
financial support of this work (grant No. N N310 149335). |
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