Vol. 21, issue 11, article # 4

pdf Aponasenko A. D. Spectral analysis of the natural organic matter adsorbed on particles of different size fractions. // Atmospheric and oceanic optics. 2008. V. 21. No. 11. P. 821-824.
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pectral characteristics of light absorption by the total organic matter (TOM), which comes to the water in a dissolved form and is adsorbed by the organic matter on particles of mineral suspension (AOM) are considered. The adsorption of TOM on particles of suspension leads to formation of the suspended particulate organic matter (POM). TOM and POM are organomineral complexes. The content of TOM and AOM was estimated by spectral absorption indices before and after filtration of water samples. Nuclear filters with a pore size from 0.25 to 4.5 µm were used in different combinations. The spectral dependence of the absorption index a(λ) of ТОМ and АОМ was approximated by the exponent a(λ) = K exp(-Sλ), where K is a proportionality factor; S is the slope of the absorption spectrum at a semi-logarithmical scale, nm-1. The total amount of AOM is shown to be dependent on the ratio of TOM to the content of the mineral suspended matter М. The S increases with the increase of the ratio ТОМ/М, while the number of POM particles and specific absorption index of light decrease. The decrease of filter pores leads to changes in spectral characteristics of light absorption for the filtered water (S of the filtrate increases). This is caused by the preferable absorption of TOM molecules with higher molecular weight, which are characterized by smaller values of S. For POM fractions of 2.87–4.5; 1.76–2.87; 1.09–1.76, and 0.5–1.09 µm, the slope of the spectrum is 0.0072; 0.0089; 0.0119 and 0.0143 nm-1, respectively.


TOM, AOM, POM, light absorption spectra, POM size fractions