Isolation of humic acid from oxidized lignite and complexation with metal cations
| Autor: | Minela Sisic, Melita Huremović, Benjamin Catovic, Majda Srabovic |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2017 |
| Předmět: |
chemistry.chemical_classification
Chromatography Chemistry 020209 energy General Chemical Engineering complexation 010401 analytical chemistry coal oxidation 02 engineering and technology General Chemistry humic acid Optical density lcsh:Chemical technology 01 natural sciences complex mixtures 0104 chemical sciences Metal visual_art 0202 electrical engineering electronic engineering information engineering visual_art.visual_art_medium Humic acid lcsh:TP1-1185 optical density Nuclear chemistry |
| Zdroj: | Hemijska Industrija, Vol 71, Iss 4, Pp 319-327 (2017) |
| ISSN: | 2217-7426 |
| Popis: | Lignite is brown coal, which in its composition contains humic acids. Humic acids are produced by coal combustion, which leads to the enrichment of coal humic acids. Lignite, from the opet pit mine Sikulje, lignite ore ?Kreka?, Bosnia and Herzegovina, was fragmented and sieved to the appropriate size and used as a base material. The isolation of humic acid was carried out from pre-oxidized and dried lignite after which it was refined. Identification thus obtained humic acids was carried out by FTIR spectroscopy and its characterization of UV analysis which is determined by optical density of isolated humic acid and its complexation with metal cations. Data obtained by FTIR spectroscopic analysis of isolated humic acids show no significant structural and chemical difference in relation to the spectrum obtained for standard humic acids (Sigma Aldrich). UV analysis showed that isolated and standard humic acid have E4/E6 ratio in an appropriate range of 3?5, which indicates the presence of a large number of aliphatic structure. Based on the degree of humification was found that the isolated humic acids belong to the type B standard while humic acids belong to type A. The most important property of the humic substances is the ability to interact with the metal ions forming soluble or insoluble complexes which possess different chemical and biological properties and stability. The nature of the complex between humic acid and metal cation derived from the heterogeneous, polyelectric and polydispersive character humic acids that occurs due to the presence of a large number of functional groups. Complexation of humic acid is carried out with different concentrations of metal nitrate solutions and at different pH values. Different amounts of humic acids were used for the complexation. The amount of the free metal ions was measured with the ICP-OES methode. The data were also statistically analyzed with ANOVA. The results showed that increasing the pH reduces the concentration of metal ions adsorbed on humic acid and by increasing the concentrations and amounts of metal humic acid that power increases. On the basis of the difference in absorbance between metals and humic acids can be said that there is an interaction between the metal and the ligand and is based on absorbance values obtained can be determine the next set of metal binding to humic acids Pb>Zn>Ni>Cu. |
| Databáze: | OpenAIRE |
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