Mechanochemical Solid-Phase Reactions of Humic Acids from Brown Coal with Sodium Percarbonate

Abstract

The solid-phase reaction of sodium percarbonate with brown coal was investigated. The results of determining the effect of a peroxide component of sodium percarbonate on an increase in the yield of humic acids as a result of the reaction are presented. It was found that the mechanism of radical oxidation makes a significant contribution to the course of the reaction. Changes in the structure of humic acids because of oxidation in the mechanochemical reaction of brown coal with sodium percarbonate were studied by IR spectroscopy and elemental analysis. An increase in the concentration of phenolic and carboxyl groups in the structure of humic acids from brown coal after the reaction was caused by the appearance of new groups as a result of oxidation and their release due to the destruction of stable complexes with metals.