Abstract
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.
Highlights
Ligniti su mrki ugljevi u kojima je još dobro očuvana anatomska građa karakteristična za drvo
Ako se za stvaranje kompleksnih spojeva koristi 50 mg huminske kiseline pri pH od 7,5 i koncentraciji od 5·10-5 mol/L tek 65,32 % bakra će se vezati za huminsku kiselinu
Determined series of metals binding to the isolated humic acids
Summary
Ligniti su mrki ugljevi u kojima je još dobro očuvana anatomska građa karakteristična za drvo. Glavne hemijske supstance koje grade mrki ugalj su: huminska kiselina, nerastvorljive huminske materije i bitumeni a kod ksilitskih mrkih ugljeva (lignita) ima još i celuloze, lignina i hemiceluloze. Priroda stvaranja kompleksa između huminskih kiselina i katjona metala potiče od heterogenog, polielektričnog i polidisperzivnog karaktera huminske kiseline koji se javlja zbog prisustva velikog broja funkcionalnih grupa [7]. Zbog prisustva funkcionalnih grupa u njihovoj strukturi, huminske kiseline su ekološki važne kada je u pitanju kruženje metala u pri-. Huminske kiseline imaju prirodna i izražena adsorpcijska svojstva koja se odnose na transport i akumulaciju teških metala. One mogu kontrolisati ponašanje teških metala u okolini tako što stupaju u interakciji sa metalima stvarajući komplekse što zavisi o karakteristikama huminske kiseline i koncentracije metalnih jona, pH vrednosti, itd. Cilj ovog rada jeste sledeće: ̶ Odrediti sadržaj frakcija huminskih kiselina u uzorcima lignita i izolirati čistu huminsku kiselinu iz lignita. ̶ Ispitati da li huminska kiselina može kompleksirati i imobilizirati rizične elemente njihovim vezivanjem u huminskom (organo-mineralnom) kompleksu. ̶ Ispitati uticaj parametara pH vrednosti i koncentracije otopina elektrolita ispitivanih metala (Pb, Cu, Zn i Ni) na kompleksaciju sa huminskom kiselinom
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
