Investigation of the Characteristics of Humic Acids Based on Kazakhstan’s Local Coal Mining Waste
Abstract
This study presents the synthesis and comparative characterization of humic acids extracted from brown coals of the Kuznetsk and Kumyskuduk deposits in Kazakhstan. Advanced analytical techniques, including infrared (IR) spectroscopy, elemental analysis, thermogravimetric (TGA/DSC) analysis, scanning electron microscopy (SEM), UV-Vis spectroscopy, and band gap analysis, were employed to evaluate their physicochemical properties. The results revealed marked differences in elemental composition, functional group distribution, thermal stability, surface morphology, and optical properties, reflecting the distinct geological origins of each deposit. Notable variations in pH, titratable acidity, and the ratio of carboxyl to phenolic hydroxyl groups suggest differences in buffering capacity and sorption behavior. The higher concentrations of carboxyl and hydroxyl groups in some samples enhance their potential for complexation and adsorption processes. This comparative analysis highlights the potential of these humic acids for use in agriculture, environmental remediation, and wastewater treatment. The findings contribute to a deeper understanding of how geological factors influence the structural and functional characteristics of humic substances, broadening their scope of practical applications and guiding future material development.