Composition of humic substances in oxidized brown coal from Mongolia

Abstract

The composition and properties of humic substances and residual coals separated from naturally or artificially oxidized (with 20% nitric acid, 30% hydrogen peroxide, and 4.8% potassium permanganate) brown coal samples with various initial degrees of humification from the Ulaan Ovoo deposit were studied using elemental, structural, and spectroscopic analysis (IR, UV, 13C NMR, and EPR spectroscopy).