Abstract
Introduction. Humic substances are multifunctional organic compounds; modification of their macromolecules allows obtaining new compounds with tailored properties and diverse compositions. Research is ongoing, but harsh conditions often lead to structural degradation. Therefore, chemical modification of humic compounds under mild conditions using affordable reagents is relevant for improving properties and expanding applications. The aim is to study the influence of various factors on obtaining new compounds through the interaction of sodium humate and aluminum orthophosphate. Methods. Standard methods, functional and X-ray diffraction analysis, Fourier-transform infrared spectroscopy. Results and Discussion. The study determined the dependence of the modification process of sodium humate derived from lignite with aluminum orthophosphate on the ratio of initial substances, temperature, and time. Analysis showed that by changing the solid-to-liquid ratio from 1:5 to 1:15, temperature from 20°C to 80°C, and time from 10 to 120 minutes, the yield of humic acids increases to 4.20%, N content – to 1.15%, P2O5 – to 31.18%, COOH groups – to 1.91 mmol/g, OHphen. – to 1.01 mmol/g, and static exchange capacity – to 14.73 mg-eq/g. Conclusion. It was found that the interaction of sodium humate with aluminum orthophosphate involves ion exchange and complexation reactions. The resulting organomineral compounds exhibit increased content of acidic groups, humic acids, phosphorus, and nitrogen. Chemical modification of humates with phosphates of varying basicity under mild conditions can produce humate-containing preparations with high biological activity and efficiency for use in agriculture, industry, and environmental purposes.