Detail publikace

Dissociation ability of humic acids: Spectroscopic determination of pKa and comparison with multi-step mechanism.

KLUČÁKOVÁ, M. KOLAJOVÁ, R.

Originální název

Dissociation ability of humic acids: Spectroscopic determination of pKa and comparison with multi-step mechanism.

Typ

článek v časopise ve Web of Science, Jimp

Jazyk

angličtina

Originální abstrakt

Humic acids are operationally defined as the fraction of humic substances which is not soluble under acidic conditions. This, does not mean, however, that their solid particles easily dissolve in water. Experimental results suggest that the dissolving of solid humic acids in an aqueous environment is more complex than the conventional solubility behaviour of sparingly soluble solids. The multi-step mechanism of their interaction with water includes partial equilibrium dissolution as well as direct equilibrium dissociation from the solid state. In this work, the pKa value of the dissolved humic acid fraction was determined on the basis of changes in the shape and intensity of their UV/VIS spectra measured in media with various values of pH. The shape of the spectra depends on the pH value, because acidic and alkaline media, in which these compounds are dissolved, shift their dissociation equilibrium towards non-dissociated molecules or to completely dissociated species. The aim of this work was to characterize the dissociation behaviour of selected humic samples by means of dissociation constants using this method. It was shown that the obtained values of pKa characterize the real dissociation behaviour of humic acids in an aqueous environment and can be used as the mean or effective value of pKa corresponding with the multi-step mechanism of dissociation of humic acids.

Klíčová slova

Reactivity; Diffusion; Humic Acids; Hydrogels

Autoři

KLUČÁKOVÁ, M.; KOLAJOVÁ, R.

Rok RIV

2014

Vydáno

12. 2. 2014

Nakladatel

REACTIVE & FUNCTIONAL POLYMERS,

Místo

NETHERLANDS

ISSN

1381-5148

Periodikum

REACTIVE & FUNCTIONAL POLYMERS

Ročník

78

Číslo

1

Stát

Nizozemsko

Strany od

1

Strany do

6

Strany počet

6

BibTex

@article{BUT106108,
  author="Martina {Klučáková} and Romana {Kratochvílová}",
  title="Dissociation ability of humic acids: Spectroscopic determination of pKa and comparison with multi-step mechanism.",
  journal="REACTIVE & FUNCTIONAL POLYMERS",
  year="2014",
  volume="78",
  number="1",
  pages="1--6",
  doi="10.1016/j.reactfunctpolym.2014.02.005",
  issn="1381-5148"
}