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Spectrofluorymetry in application to oil-in-water emulsion characterization

Otremba Z., Baszanowska E., Toczek H.

Journal of KONES

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2011

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Vol. 18, No. 3

317-321

EN

The question of identifying the type of oil in exploitation of engine room is associated with both the quality of ship consumables (fuels and lubricants) and the composition and origin of oil in settling tanks or in dumping water. Related issue is the possibility of determining the origin of oil, which is detected in the marine environment. The key question is how oils vary in their ability to fluorescence, understood as the shapes of fluorescence spectra obtained for different wavelengths of light exciting fluorescence. In this paper we present spectra of fluorescence for six chosen oils. Those oils were previously dispersed (emulsified) in the seawater, then extracted into hexane. Fluorescence spectra were obtained using fluorescence spectrometer Perkin Elmer LS55, for excitation wavelengths in the range from 240 nm to 500 nm, and emission wavelengths from 300 nm to 790 nm. In this paper there is shown that in general both total intensity of fluorescence and shapes of spectra of fluorescence depend on the excitation wavelength and are differ for various kinds of oil. In order to visually show the differences in fluorescence abilities of various oils, the results of measurement were placed on a chart of fluorescence intensities in the function of both variables: the excitation wavelength and the emission wavelength (so called the total fluorescence spectra). Analyses of results of the described studies confirm that the different oils fluoresce differently and identification of type of oil is possible by fluorescence spectrophotometry.

2

Optical properties of fuels and lubricants vs. aquatic environment protection issues

Otremba Z., Toczek H.

Journal of KONES

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2011

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Vol. 18, No. 4

325-330

EN

Oils can be optically described by two parameters: light absorption coefficient and light refraction coefficient. Spectrum of absorption coefficient manifests itself in colour of oil, whereas spectrum of refraction coefficient impacts on both refractive and reflective properties of interface between oil and surroundings. Both spectra of absorption coefficient and refraction coefficient have distinctive slopes in ultraviolet edge of spectrum where values of mentioned coefficients decrease from extremely high in ultraviolet to relatively low in visual range. Possibility of perceiving of oil existing in the form of thin film or in the form of an emulsion depends on ambient light conditions and on mentioned optical properties. Additionally perceiving of oil depends on thickness of the oil film and on type of substrate on which oil is spread (water, metal etc.), as well as - if emulsion oil-in-water or water-in-oil is considered - on the droplets size distribution. The present paper begins with a review of optical properties of several oils. Next, an impact of changes of those properties on optical properties of an oil film (spread on water) as well as an impact of those properties on optical properties of oil-in-water emulsion is explained. Finally, exemplary results of numerical simulation of light transfer in marine environment (using above optical properties) - e.g. angular distributions of optical contrast of both sea areas clean and polluted by an oil-film are presented.

3

Adoption of the time resolved fluorescence to oil type identification

Baszanowska E., Otremba Z., Rohde P., Zieliński O.

Journal of KONES

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2011

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Vol. 18, No. 2

25-29

EN

The present development of a basic science, including physics of stimulated emission of light, opens up new diagnostic possibilities in relation to the quality of oils, including marine fuels and lubricants. In complicated chemical composition of oils both light absorbing compounds and compounds that emit light (fluorescent) are included. This causes the formation of complex structures in the spectral plots of fluorescence intensity as a function of wavelength of light exciting fluorescence and as a function of the wavelength of light emitted. Since the fluorescence excitation occurs in a short time of its disappearance. The shape of the fluorescence decay function depends on the chemical composition of oil, therefore, includes a mention of its kind, quality, level of degradation, and the like. In this paper exemplary charts of the intensity decay curves in different parts of the fluorescence spectra are shown (for light fuel). Presented charts are obtained using the experimental device constructed in Bremerhaven University of Applied Sciences (Germany) and are the attempt to use ability of oil substance to manifest its composition in the form of the fluorescence decay curve. An analysis of the chart shows that decay of fluorescence in this case is described by biexponential curve, therefore a kind of oil can be represented by two numerical values - two decay time constants. Operational use of this method will be possible only after a comparative study of different types and quality of oil in relation to the shape of the fluorescence decay curves.