Analysis of Structural Features of Humic Acids Fractions after Mechanochemical Modification

Abstract

Humic substances are the major components of soil, peat and brown coal. They can be fractionating into fulvic acids (FA), brown humic acids (BHA) and gray humic acids (GHA). In this work we investigated the influence of mechanochemical modifications on structural composition of HAs main fractions using the methods of IR and 1H MRS spectroscopy. The IR spectroscopy results has shown that HA has different chemical composition in comparison with GHA and BHA. Potentiometric titration showed that mechanoactivation (MA) with thiourea increases the amount of oxygen-containing groups up to 2.5. For the first time we studied the impact of modifying agent of thiourea on the structural composition and acid-base properties of HAs major fractions - GHA and BHA during the mechanoactivation process.