Comparative IR spectral characteristics of humic acids from peats of different origin in the Tomsk area

Influence of the humification process on the properties of peat humic acids Comparative and complex characterisation of peat humic acids (HAs) isolated from peat profiles of different origin in Latvia was conducted. Elemental and functional analysis of the isolated HAs was made and their acidity and molecular weight were estimated. Spectral characterisation included UV-Vis, IR, electron spin resonance and fluorescence spectra. Structural characterisation of HAs was by both 1H and13C nuclear magnetic resonance spectra. Properties of HAs isolated from the Latvian peat were compared with HA from other sources (soil, water, coal and synthetic humic substances). Major properties of peat HAs depended on their origin, indicating the importance of humification processes. HAs isolated from peat of more recent origin were more similar to soil Has, while there was a greater degree of humification in part from older sources.

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Humic acids characterization by EDXS and 13C NMR spectroscopy

Acta Universitatis Agriculturae et Silviculturae Mendelianae Brunensis ◽

10.11118/actaun201058010139 ◽

2010 ◽

Vol 58 (1) ◽

pp. 139-146

Author(s):

Ľubica Pospíšilová ◽

Naděžda Fasurová ◽

Tibor Liptaj ◽

Lubomír Jurica

Keyword(s):

Humic Acids ◽

Quality Evaluation ◽

Spectral Characteristics ◽

13C Nmr Spectroscopy ◽

Aromatic Carbon ◽

X Ray ◽

Aliphatic Carbon ◽

C Nmr

Determination of humic acids spectral characteristics performed fast and convenient method for their quality evaluation. Humic acids (HA) were isolated from five different soil types (Luvi-haplic Chernozem, Haplic Luvisol, Haplic Cambisol, Leptic Cambisol and Eutric Cambisol) and from compost. Basic soil characteristics were determined by commonly used methods. Fractional compositon of humus showed that humic acids content was decreasing in order: compost > Luvi-haplic Chernozem > Haplic Luvisol > Eutric Cambisol > Haplic Cambisol > Leptic Cambisol. Isolated humic acids preparations were characterized comparatively by chemical and spectroscopic methods. Elemental analysis showed the highest carbon content in Luvi-haplic Chernozem HA. The lowest carbon amount was in Eutric Cambisol. Energy–dispersive X-ray spectroscopy detected elementsin situin HA molecule. All samples contained Fe, Cu, Zn, Ti, Ca, K, S, P, Si and Br. Practically no differences in elements content between soil humic substances and compost were detected. The amount of aromatic carbon was higher in Luvi-haplic Chernozem to compare with other samples. Humic acids isolated from Cambisols, on the basis13C NMR spectroscopic data, showed that all samples contained less aromatic carbon and significantly more aliphatic carbon.

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TiO2-assisted photocatalytic degradation of humic acids: effect of copper ions

Water Science & Technology ◽

10.2166/wst.2010.174 ◽

2010 ◽

Vol 61 (10) ◽

pp. 2581-2590 ◽

Cited By ~ 7

Author(s):

C. S. Uyguner ◽

M. Bekbolet

Keyword(s):

Humic Acid ◽

Photocatalytic Degradation ◽

Humic Acids ◽

Rate Constants ◽

Copper Ions ◽

Degradation Kinetics ◽

Spectral Characteristics ◽

Molecular Size ◽

Spectroscopic Techniques ◽

Concentration Effects

The present study investigated the removal efficiency of aqueous humic acid solutions by TiO2 photocatalytic degradation in the presence of Cu(II) species. The pseudo-first-order kinetics revealed rate constants as 9.87 × 10−3, 7.19 × 10−3, 3.81 × 10−3 min−1 for Color436, UV254 and TOC, respectively. Comparatively, lower rate constants were attained with respect to photocatalytic degradation of humic acid. Considering the source-dependent diverse chemical and spectral characteristics of NOM, a particular interaction would be expected for humic acid with Cu(II) species (0.1 mg L−1). The presence of copper ions significantly altered the photocatalytic degradation kinetics of humic acids in relation to the concentration effects of humic acid as expressed by spectroscopic parameters and TOC. Batch equilibrium adsorption experiments revealed a distinct Langmuirian-type adsorptive behavior of humic acid onto TiO2 both in terms of UV254 and Color436 and a C-type adsorption isotherm was attained for TOC. KF values displayed an inconsistent effect of Cu(II) species, while adsorption intensity factor 1/n<1 denoted a prevailing favorable type of adsorption for Color436 and UV254. Because of the role of intra- and intermolecular interactions between copper ions and humic molecular size fractions, spectroscopic techniques were also employed for the assessment of the adsorption as well as photocatalytic degradation efficiencies.

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Triallate adsorption onto humic acids of different origin and nature

Chemosphere ◽

10.1016/s0045-6535(99)00102-2 ◽

1999 ◽

Vol 39 (2) ◽

pp. 183-198 ◽

Cited By ~ 8

Author(s):

V. D'Orazio ◽

E. Loffredo ◽

G. Brunetti ◽

N. Senesi

Keyword(s):

Humic Acids ◽

Different Origin

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Humic-like acid derived from 1,2-naphthoquinone

French-Ukrainian Journal of Chemistry ◽

10.17721/fujcv8i2p140-149 ◽

2020 ◽

Vol 8 (2) ◽

pp. 140-149

Author(s):

Valentina Litvin ◽

Roger Abi Njoh

Keyword(s):

Humic Acids ◽

Group Composition ◽

Spectral Characteristics ◽

Original Method ◽

Volumetric Method ◽

Structural Group ◽

Singlet Signal ◽

G Factor ◽

Redox Capacity ◽

Structural Group Composition

A new fast and original method for producing synthetic humic acids by oxidation of 1,2-naphthoquinone by oxygen in an alkaline medium has been proposed. The elemental, structural-group composition and spectral characteristics of the obtained humic-like substances correspond to those of natural humic substances. The stoichiometry of the reaction was established by the volumetric method. The redox capacity of humic acids increased from 0.43 to 3.68 mmol∙g-1 with increasing solution from pH 5 to 11. Humic-like acids featured an ESR singlet signal with a width of 3.8 Gauss and g-factor close to the g-factor of the free electron (g = 2.0033).

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