Authors: N.I. Fedorova, I.Yu. Zykov, V.E. Tsvetkov

Title of the article: Physico-chemical and sorption properties oxidized brown coal carbonysates

Year: 2026, Issue: 3, Pages: 79-88

Branch of knowledge: 2.6.12. Chemical technology of fuel and high-energy substances

Index UDK: 662.74:541.13:544.6

DOI: 10.26730/1999-4125-2026-3-79-88

Abstract: Purification of natural and wastewater from harmful impurities, including heavy metals, is quite effectively carried out through sorption technologies that use various activated carbons. The effectiveness of the sorption materials used depends on the porous structure and the presence of various functional groups on their surface. The modification of carbon sorbents is solved by purposefully affecting their surface properties to form various sorption centers, change the bulk properties of materials and the chemical properties of the surface. Therefore, the development of various technological approaches to the synthesis and modification of carbon sorbents is an urgent task. The purpose of the study was to study the effect of oxidative modification of lignite carbonates by nitric acid on changes in their physico-chemical and sorption properties. Brown coal from the Berezovsky mine (Krasnoyarsk Territory, Russian Federation) was used as a coal raw material. Carbonation of coal raw materials (particle size 1-3 mm) was carried out by the box coking method in a muffle furnace with a temperature range from 800 ° C to 1000 ° C. The oxidative modification of carbonysates was carried out with dilute nitric acid (acid: water ratio = 1:1) by boiling for 3 hours. The results of chemical and physico-chemical analysis methods have shown that the oxidative modification of carbonizates leads to a decrease in their ash content, an increase in the atomic O/C ratio and the number of various forms of oxygen-containing functional groups on the surface, and also leads to an increase in all textural characteristics (specific surface area and total pore volume). It was found that the specific surface area of the samples increases by an average of 1.5 times. It has been shown that carbonisates modified with nitric acid exhibit greater sorption activity with respect to copper and lead cations. The sample with the highest specific surface area and the content of oxygen-containing functional groups has the maximum sorption activity. The degree of extraction of lead cations by this sample increased almost 2 times.

Key words: brown coal carbonisates oxidative modification surface functional groups specific surface area adsorption

Receiving date: 10.03.2026

Approval date: 15.06.2026

Publication date: 27.08.2026

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