Detail publikace

The kinetics of thermo-oxidative humic acids degradation studied by isoconversional methods

VÁLKOVÁ, D. KISLINGER, J. PEKAŘ, M. KUČERÍK, J.

Originální název

The kinetics of thermo-oxidative humic acids degradation studied by isoconversional methods

Anglický název

The kinetics of thermo-oxidative humic acids degradation studied by isoconversional methods

Typ

článek v časopise - ostatní, Jost

Jazyk

čeština

Originální abstrakt

Humic acids represent a complicated mixture of miscellaneous molecules formed as a product of mostly microbial degradation of dead plant tissues and animal bodies. In this work, lignite humic acids were enriched by model compounds and the model-free method suggested by Šimon was used to evaluate their stability over the whole range of conversions during the first thermooxidative degradation step. The kinetic parameters obtained were used to predict the stability at 20 and 180C, respectively, which served for the recognition of processes induced by heat and those naturally occurring at lower temperatures. Comparison of the conversion times brought a partial insight into the kinetics and consequently into the role of individual compounds in the thermooxidative degradation/stability of the secondary structure of humic acids. It has been demonstrated that aromatic compounds added to humic acids, except pyridine, increased stability of humic acids and intermediate chars. The same conclusion can be drawn for acetic and palmitic acids. Addition of glucose or ethanol decreased the overall humic stability; however, the char of the former showed the highest stability after 40% of degradation.

Anglický abstrakt

Humic acids represent a complicated mixture of miscellaneous molecules formed as a product of mostly microbial degradation of dead plant tissues and animal bodies. In this work, lignite humic acids were enriched by model compounds and the model-free method suggested by Šimon was used to evaluate their stability over the whole range of conversions during the first thermooxidative degradation step. The kinetic parameters obtained were used to predict the stability at 20 and 180C, respectively, which served for the recognition of processes induced by heat and those naturally occurring at lower temperatures. Comparison of the conversion times brought a partial insight into the kinetics and consequently into the role of individual compounds in the thermooxidative degradation/stability of the secondary structure of humic acids. It has been demonstrated that aromatic compounds added to humic acids, except pyridine, increased stability of humic acids and intermediate chars. The same conclusion can be drawn for acetic and palmitic acids. Addition of glucose or ethanol decreased the overall humic stability; however, the char of the former showed the highest stability after 40% of degradation.

Klíčová slova

lignite humic acids, thermal analysis, isoconversional methods, DSC

Klíčová slova v angličtině

lignite humic acids, thermal analysis, isoconversional methods, DSC

Autoři

VÁLKOVÁ, D.; KISLINGER, J.; PEKAŘ, M.; KUČERÍK, J.

Rok RIV

2007

Vydáno

1. 10. 2007

Nakladatel

Springer

ISSN

1388-6150

Periodikum

Journal of Thermal Analysis and Calorimetry

Ročník

2007

Číslo

89

Stát

Maďarsko

Strany od

957

Strany do

964

Strany počet

8

BibTex

@article{BUT44241,
  author="Dana {Švejdová} and Jiří {Kislinger} and Miloslav {Pekař} and Jiří {Kučerík}",
  title="The kinetics of thermo-oxidative humic acids degradation studied by isoconversional methods",
  journal="Journal of Thermal Analysis and Calorimetry",
  year="2007",
  volume="2007",
  number="89",
  pages="957--964",
  issn="1388-6150"
}