Spectroscopic studies of humic acids from subsurface sediment samples collected across the Aegean Sea

Sakellariadou, Fani

doi:10.12681/mms.166

Cited by 22 publications

(12 citation statements)

References 17 publications

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“…1) of HAs at an excitation wavelength of 340 nm show emission maxima at 490 nm and ~650 nm. The emission maxima at 490 nm is in slightly higher range which is typical to that of terrestrial sources as compared to those from marine samples which generally show a maximum emission intensity which varies within a lower wavelength range, 410-450 nm (Sakellariadou, 2006). This feature probably highlights the contribution of terrestrial sources in the origin of complex and heterogeneous HAs of mudbank sediments as discussed in earlier.…”

Section: Fluorescence Emission Spectrasupporting

confidence: 54%

Genesis of structural features of humic acids from the sediments of a high productive coastal zone

Prashob

Nair

2014

Geochem. J.

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Section: Fluorescence Emission Spectrasupporting

confidence: 54%

Genesis of structural features of humic acids from the sediments of a high productive coastal zone

Prashob

Nair

2014

Geochem. J.

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“…When calcite was added to solutions of humic acid sodium salt, barely any changes were observed in the IR spectra (Figure c, left). Only at the highest concentration of humic acid (1.5 wt %) does a weak signal appear at 1593 cm −1 that can be attributed to the aromatic C=C double bonds conjugated with C=O and/or COO − [ Sakellariadou , ] that are typical of humic materials. The results suggest that there is little interaction and no chemical transformations associated with the addition of calcium carbonate to humic acid solutions.…”

Section: Resultsmentioning

confidence: 99%

Infrared extinction spectroscopy and micro‐Raman spectroscopy of select components of mineral dust mixed with organic compounds

et al. 2013

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[1] Radiative transfer calculations as well as satellite and ground-based retrieval algorithms often use Mie theory to account for atmospheric mineral dust. However, the approximations used in Mie theory are often not appropriate for mineral dust and can lead to inaccuracies in modeling optical properties. Analytic models that are based on Rayleigh theory and account for particle shapes can offer significant advantages when used to model the IR extinction of mineral dust in the accumulation size mode. Here we extend our investigations of the IR optical properties of mineral dust to include samples that have been processed with organic acids. In particular, we aerosolize several individual components of mineral dust with organic compounds that are common in the atmosphere. Through online and offline analysis of the resulting aerosol particles combining Fourier transform infrared (FTIR) extinction spectroscopy, micro-Raman spectroscopy, and scanning electron microscopy, we have identified three distinct outcomes of the interactions, which depend on the nature of the mineral and the organic acid: reactions with segregation of the products within the particle, formation of a uniform coating on the particle, or a formation of external mixture when there is no significant chemical interaction. Analysis of FTIR extinction spectra of the different dust components that have undergone processing shows red shifts of the prominent IR resonance peaks. The extent of the red shift, which varies from 2 to 10 cm À1 , depends on the mineral and the nature of the interaction. Spectral simulations showed that the deviation from Mie theory becomes even more pronounced for these processed mineral dust aerosol components.

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“…The intensity of bands expressed in absorbance units showed the highest content of OH groups in HA2 and HA4 and the lowest in HA1 and HA8. Alkanes and cycloalkanes were absorbed in the range of 2 850-3 000 cm -1 (Pospíšilová et al, 2008;Sakellariadou, 2006). In general, these bands are very strong in humic acids and their location should not change more than ±10 cm -1 .…”

Section: Properties Of Peaty-muck Soils and Humic Acids -Statistical mentioning

confidence: 92%

“…Figure 1 depicts such spectra for selected samples of humic acids (HA 2, 3, 5, and 7). The spectra show bands coming from stretching vibrations of phenolic and alcohol OH groups at a wavenumber range from 3401 to 3415 cm -1 (Sakellariadou, 2006). The intensity of bands expressed in absorbance units showed the highest content of OH groups in HA2 and HA4 and the lowest in HA1 and HA8.…”

Section: Properties Of Peaty-muck Soils and Humic Acids -Statistical mentioning

confidence: 99%

Statistical Relationship between Selected Physicochemical Properties of Peaty-Muck Soils and their Fraction of Humic Acids

Boguta¹,

Sokołowska²

2014

International Agrophysics

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A b s t r a c t. Influence of humic acids on soil environment is still subject of scientific discussions. The aim of above studies was to investigate the relationships between selected physicochemical properties of eleven peaty-muck soils and properties of humic acids isolated from these soils. The following parameters were determined for soils: total and organic carbon, density, ash, humification, and the water absorption index. Humic acids were described by: absorbance at 280 nm, absorbance ratios at 465 and 665 nm, at 260 and 665 nm, elemental composition and atomic ratios: H/C, O/H, O/C, C/N, the degree of internal oxidation, and the content of carboxylic and phenolic groups. Statistical analyses showed that an increase in density, humification, and water absorption indices of soils caused a significant increase in the humic acid parameters: absorbance at 280 nm, the oxygen content, O/H, O/C ratios, internal oxidation degree, and functional groups. Statistically significant negative correlations were found for the same parameters of soils and for the hydrogen and carbon content as well as the H/C ratio of humic acids. The relationships showed that there was a possibility to express the properties of humic acids on the basis of more simple parameters measured for soil and without time-consuming isolation of humic acids.K e y w o r d s: organic soils, humic acids, humification

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Spectroscopic studies of humic acids from subsurface sediment samples collected across the Aegean Sea

Abstract: Natural humic acids are biogenic, structurally complex and heterogeneous, refractory, acidic, yellow-to black-coloured

Cited by 22 publications

References 17 publications

Genesis of structural features of humic acids from the sediments of a high productive coastal zone

Genesis of structural features of humic acids from the sediments of a high productive coastal zone

Infrared extinction spectroscopy and micro‐Raman spectroscopy of select components of mineral dust mixed with organic compounds

Statistical Relationship between Selected Physicochemical Properties of Peaty-Muck Soils and their Fraction of Humic Acids

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