THERMODYNAMIC ANALYSIS OF CU(II) AND PB(II) ION BINDING TO HUMIC ACIDS ISOLATED FROM DIFFERENT ORIGINS AND STRUCTURAL CHARACTERIZATION USING FTIR AND 13C NMR SPECTROSCOPY

1 TURKEOVA Irena
Co-authors:
1 ENEV Vojtech 1 KLUCAKOVA Martina
Institution:
1 Materials Research Centre, Brno University of Technology, Faculty of Chemistry, Brno, Czech Republic, EU, xcturkeovai@fch.vutbr.cz
Conference:
7th International Conference on Nanomaterials - Research & Application, Hotel Voronez I, Brno, Czech Republic, EU, October 14th - 16th 2015
Proceedings:
Proceedings 7th International Conference on Nanomaterials - Research & Application
Pages:
645-649
ISBN:
978-80-87294-59-8
ISSN:
2694-930X
Published:
11th January 2016
Proceedings of the conference were published in Web of Science and Scopus.
Metrics:
24 views / 4 downloads
Abstract

The aim of this work was study molecular and quantitative analysis of metal ion binding to humic acids (HAs). The object of our study were two various samples of HAs. HAs were isolated from South-Moravian lignite from the mine Mír (locality Mikulčice, Czech Republic) and compost which was obtained from the composting plant in Náměšť n. Oslavou, Czech Republic. Isolation of HAs was performed according to the procedure recommended by the International Humic Substances Society (IHSS). The reactivity (thermodynamics) of humic acids (HAs) and metals was studied by isothermal titration calorimetry (ITC). As model metals were chosen Cu (II) and Pb (II) ions. ITC was observed reaction enthalpy, Gibbs energy, enthropy and the amount of metal bound to a specific humic acid. The HAs were characterized and compared using spectroscopic techniques, including FTIR and liquid-state 13C NMR spectroscopy. Infrared spectroscopy is a useful technique in characterization of structure, functional groups and formation modes of HAs. 13C NMR spectra of HAs were obtained with a Bruker Avance III NMR spectrometer. For data analysis, the spectra were divided into chemical shift regions assigned to the following classes of chemical groups: alkyl C (0–45 ppm), O-alkyl C (45–106 ppm), aromatic C (106–165 ppm), and carbonyl and carboxyl C (165–220 ppm), respectively. Aromaticity (fa), hydrophilicity and hydrophobicity ratio (Hfi/Hfo) and biological activity (BiA) of HAs were calculated from the area of the NMR spectra.

Keywords: humic acids; isothermal titration calorimetry; complexation; metal ions
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