humic acids

Optimisation of the Extraction Process of Toluene and Humic Acid Extract from Brown Coal

Lignite (brown coal) is a promising source of humic acids (HAs) and toluene-soluble extracts (bitumen "A"), which have applications as soil conditioners/biostimulants (HAs) and hydrophobic coatings or polymer additives (toluene extract). This study optimized their sequential extraction from Ukrainian lignite, evaluating yield trade-offs and structural properties. Four extraction variants were tested. Conventional toluene-first extraction (Variant 0) yielded the highest toluene extract (14.86 wt. %), but lower HAs (41.0 wt.

Characterization and Interaction of Humic Acids with Metal Ions as a Function of Solution pH

This study examines the solubility of humic acids as a function of solution pH and their interactions with di- and trivalent metal ions at different pH values. It has been observed that humic acids and their salts interact with divalent transition metal ions in aqueous solutions at low pH values. The results demonstrate that the amount of metal ions – specifically copper, cobalt, and nickel – bound to humic acids increases almost linearly with their initial concentration. Moreover, the amount of bound metal ions rises as the pH of the medium increases.

Valorization of Lignite Use in “Green” Technologies: A Review

The increased utilization of lignite in "green" technologies represents a critical step toward the rational use and valorization of low-grade fossil fuels. This study examines the current state of lignite deposits in Ukraine and explores its potential applications in non-energy and environmentally sustainable energy sectors. The chemical composition of humic acids derived from brown coal was analyzed, along with their ability to undergo hybrid modification with biodegradable materials such as hydrogels, biofilms, and composites.

RESEARCH ON THE EFFECT OF HUMIC SUBSTANCES-BASED PREPARATIONS IN PROMOTING SOIL BIODEGRADATION PROCESSES

The paper presents an analysis of the market of fertilizers and organic additives that promote the biodegradation of herbicide residues in the soil and ensure stable growth and development of agricultural crops. The work also presents studies of the action of biostimulants based on humic substances in promoting the activation of plant defense mechanisms when combating stress in conditions unfavorable for growth.

Мodification of road bitumen with humic acids

Modifying road bitumen of the BND 70/100 brand with humic acids was carried out. In particular, the influence of the duration of the process and the amount of addition on the quality characteristics of the binder was studied. It was established that humic acids negatively affect the plastic properties of bitumen (deteriorate the softening temperature, penetration, and ductility), positively affect its elasticity, and have practically no effect on the ability of the binder to adhere to the surface of the mineral material.

Study of Hybrid Humic Acids Modification of Environmentally Safe Biodegradable Films Based on Hydroxypropyl Methyl Cellulose

The possibility of increasing the strength and operational properties of ecologically safe biodegradable polymeric materials based on hydroxypropyl methyl cellulose by using its modification with the different types of humic acids (HAs) from lignite is considered. Hybrid ecologically safe high-strength films with antibacterial properties were obtained for the first time. Physicochemical studies and IR spectroscopy confirmed the development of hybrid structures of hydroxypropyl methyl cellulose, modified with the different types of HAs.

ANTIOXIDANT EFFECT OF HUMIC ACIDS ON RAT HEPATOCYTES

The antioxidant properties of humic acids of various origins have been investigated (from bio-humus, black soil from Ternopil region, and peat from different regions, such as: Velykyi Liubin, Drohobych and Belarus Republic). Titrimetric analysis has been shown the quantitative composition of the acidic functional groups of the obtained humic acids. According to the data of thermogravimetric analysis, the values of parameters, showing the ratio of their aliphatic to the cyclic part were determined.

Рhysical and chemical researches on the structure of humic acids

Based on the complex thermal, titrimetric and UV/Vis spectral analyzes, the structure and the content of functional groups in the molecules of humic acids obtained from different raw materials – coprolite, peat and leonardite – were investigated. The thermal stability of the substances was investigated in the air in the temperature range 20-1000°C. It has been found that the content of the aliphatic component is predominant in humic acids obtained from different raw materials.