Degradative analysis of aquatic fulvic acid: CuO oxidation versus pyrolysis after tetramethylammonium hydroxide treatments in air and helium atmospheres

Lehtonen, Tero; Peuravuori, Juhani; Pihlaja, Kalevi

doi:10.1016/j.aca.2004.02.008

Cited by 17 publications

(12 citation statements)

References 24 publications

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“…The compounds identified from the thermochemolysis and the chloroform extract qualitatively indicate that they can be related to the constituents of humic substances (Reid et al 1988;Lehtonen et al 2000Lehtonen et al , 2004Estournel-Pelardy et al 2013) in accordance with the results of the fluorescence EEM spectra. Several of these identified molecules may act as metal-binding ligands.…”

Section: Tetramethylammonium Hydroxide Thermochemolysissupporting

confidence: 74%

Study of water-extractable fractions from South Moravian lignite

et al. 2014

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International audienceLignite can be applied directly in natural form on agricultural fields as a soil conditioner. However, there is little information on leaching of risky compounds by its interaction with water. South Moravian lignite was therefore extracted with water at 25 A degrees C and 2.3 % of water-soluble fractions were obtained from lignite corresponding to 0.3 % of total organic carbon. All ten fractions form aromatic and aliphatic structures with oxygen-containing functional groups such as carboxyl groups, alcohols, ethers, esters, can be characterized as fulvic-like and humic-like substances. According to the XPS spectra, the fractions contain two nitrogen forms, one of which is ascribed to pyrroles and the second is related to protonated amines or quaternary nitrogen. Analysis at molecular level showed that the fractions contain compounds such as benzene carboxylic acids and their derivatives, small aliphatic diacids, fatty acids and polyols. Most of the identified molecules reflect clearly the presence of microbial remains in the lignite structure since microbial activity during coalification is well known. The differences between the individual fractions are negligible, especially after 21 days of extraction. From environmental point of view, it seems that the identified compounds do not represent a toxic risk

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Section: Tetramethylammonium Hydroxide Thermochemolysissupporting

confidence: 74%

Study of water-extractable fractions from South Moravian lignite

et al. 2014

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“…Thermochemolysis-TMAH results also revealed the presence of a homologous series of long-chain fatty acid methyl esters (C 8 -C 32 ) and dicarboxylic acid dimethyl esters. Lehtonen et al [142] studied Nordic aquatic reference fulvic acid by two different analytical techniques: off-line thermochemolysis-TMAH (under both air and helium atmospheres) and alkaline CuO oxidation. It was found that both techniques gave similar products (e.g.…”

Section: Thermochemolysis With Other Sample Treatmentsmentioning

confidence: 99%

Recent applications in analytical thermochemolysis

Shadkami

Helleur

2010

Journal of Analytical and Applied Pyrolysis

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“…Phenolic compounds have traditionally been considered as the main “building blocks” of humic substances [ 17 ]. In particular, phenolic acids, i.e., chemical compounds with an aromatic core and phenolic and carboxylic functions ( Figure 3 A), are valued at up to 35% in HS [ 40 ].…”

Section: Structure Of Humic Substancesmentioning

confidence: 99%

Chemical Structure and Biological Activity of Humic Substances Define Their Role as Plant Growth Promoters

2021

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Humic substances (HS) are dominant components of soil organic matter and are recognized as natural, effective growth promoters to be used in sustainable agriculture. In recent years, many efforts have been made to get insights on the relationship between HS chemical structure and their biological activity in plants using combinatory approaches. Relevant results highlight the existence of key functional groups in HS that might trigger positive local and systemic physiological responses via a complex network of hormone-like signaling pathways. The biological activity of HS finely relies on their dosage, origin, molecular size, degree of hydrophobicity and aromaticity, and spatial distribution of hydrophilic and hydrophobic domains. The molecular size of HS also impacts their mode of action in plants, as low molecular size HS can enter the root cells and directly elicit intracellular signals, while high molecular size HS bind to external cell receptors to induce molecular responses. Main targets of HS in plants are nutrient transporters, plasma membrane H+-ATPases, hormone routes, genes/enzymes involved in nitrogen assimilation, cell division, and development. This review aims to give a detailed survey of the mechanisms associated to the growth regulatory functions of HS in view of their use in sustainable technologies.

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Degradative analysis of aquatic fulvic acid: CuO oxidation versus pyrolysis after tetramethylammonium hydroxide treatments in air and helium atmospheres

Cited by 17 publications

References 24 publications

Study of water-extractable fractions from South Moravian lignite

Study of water-extractable fractions from South Moravian lignite

Recent applications in analytical thermochemolysis

Chemical Structure and Biological Activity of Humic Substances Define Their Role as Plant Growth Promoters

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