Chemistry Reference
In-Depth Information
Static and dynamic surface tension of marine water:
onshore or platform-based measurements by the
oscillating bubble tensiometer
Giuseppe Loglio
1
, Boris Noskov
2
, Piero Pandolfini
1
, and Reinhard Miller
3
1
Department of Organic Chemistry, University of Florence, Florence, Italy
2
Institute of Chemistry, St. Petersburg State University, St. Petersburg,
Russia
3
Max-Planck-Institut für Kolloid- und Grenzflächenforschung,
Potsdam/Golm, Germany
Abstract.
The functionality and performances of an oscillating bubble
tensiometer designed for the measurement of static and dynamic surface
tension of marine water samples are illustrated. The instrumentation com-
pletely works in automatic mode. Semi-continuous operation can also be
easily implemented. By virtue of its geometrical configuration, the appara-
tus shows a relative insensitivity to external disturbances, in comparison to
other measurement techniques, and consequently it can be employed even
under severe environmental conditions, such as those encountered onshore
or on platform-based locations. Experimental observations of the dynamic
surface tension response to harmonic surface area changes are reported, for
samples of sea water and for a dilute aqueous solution of a standard surfac-
tant. The observed results are considered useful for a physical characteri-
sation of marine water in respect to interfacial ocean-atmosphere pheno-
mena and processes. Furthermore, the oscillating-air-bubble tensiometer
mimics the real behaviour of the bubbles (ubiquitously present in the near
surface of the oceans) and appears to be a suitable instrument for the as-
sessment of the presence of natural and man-made adsorption-film-form-
ing organic materials at the air/water interface.
1 Introduction
Interfacial properties play an important role in many natural processes oc-
curring in the marine environment. A multitude of natural or man-made
organic substances escape homogeneous distribution in the water column
