Publication result detail
Micro-organization of humic acids in aqueous solutions
KLUČÁKOVÁ, M.; VĚŽNÍKOVÁ, K.
Original Title
Micro-organization of humic acids in aqueous solutions
English Title
Micro-organization of humic acids in aqueous solutions
Type
WoS Article
Original Abstract
The methods of dynamic light scattering and micro-rheology were used to investigate the molecular organization of humic acids in solutions. The obtained results were supplemented by ultraviolet/visible spectrometry and measurement of the zeta potential. Particle tracking micro-rheology was used for the first time as a novel method in humic research. Solutions of humic acids were prepared in three different mediums: NaOH, NaCl, and NaOH neutralized by HCl after dissolution of the humic sample. The molecular organization of humic acids was studied over a wide concentration range (0.01 – 10 g dm-3). Two breaks were detected in the obtained concentration dependencies. The rearrangements were observed at concentrations around 0.02 g dm-3 and 1 g dm-3. Changes in the measured values observed at around 0.02 g dm-3 were less noticeable and were related to the formation of particles between 100 and 1000 nm in size and the strong bimodal character of humic systems diluted by NaCl. The “switch-over point” at around 1 g dm-3 indicated changes in the secondary structure of humic acids connected with the increase in colloidal stability (decrease of zeta potential), the decrease in polydispersity, and minimal values of viscosity.
English abstract
The methods of dynamic light scattering and micro-rheology were used to investigate the molecular organization of humic acids in solutions. The obtained results were supplemented by ultraviolet/visible spectrometry and measurement of the zeta potential. Particle tracking micro-rheology was used for the first time as a novel method in humic research. Solutions of humic acids were prepared in three different mediums: NaOH, NaCl, and NaOH neutralized by HCl after dissolution of the humic sample. The molecular organization of humic acids was studied over a wide concentration range (0.01 – 10 g dm-3). Two breaks were detected in the obtained concentration dependencies. The rearrangements were observed at concentrations around 0.02 g dm-3 and 1 g dm-3. Changes in the measured values observed at around 0.02 g dm-3 were less noticeable and were related to the formation of particles between 100 and 1000 nm in size and the strong bimodal character of humic systems diluted by NaCl. The “switch-over point” at around 1 g dm-3 indicated changes in the secondary structure of humic acids connected with the increase in colloidal stability (decrease of zeta potential), the decrease in polydispersity, and minimal values of viscosity.
Keywords
Humic acid; Molecular organization; Secondary structure; Aggregation; Dynamic light scattering; Micro-rheology
Key words in English
Humic acid; Molecular organization; Secondary structure; Aggregation; Dynamic light scattering; Micro-rheology
Authors
KLUČÁKOVÁ, M.; VĚŽNÍKOVÁ, K.
RIV year
2018
Released
04.05.2017
Publisher
Elsevier
Location
Amsterdam
ISBN
0022-2860
Periodical
Journal of Molecular Structure
Volume
1144
Number
1
State
Kingdom of the Netherlands
Pages from
33
Pages to
40
Pages count
8
Full text in the Digital Library
BibTex
@article{BUT135353,
author="Martina {Klučáková} and Kateřina {Věžníková}",
title="Micro-organization of humic acids in aqueous solutions",
journal="Journal of Molecular Structure",
year="2017",
volume="1144",
number="1",
pages="33--40",
doi="10.1016/j.molstruc.2017.05.012",
issn="0022-2860"
}