The chemical analysis of humic acids and their activated forms based on brown coal from the Maikuben coal basin (Kazakhstan) was carried out. The humic aci

Physico-chemical characteristics of shugite rocks of Kazakhstan (Bakyrchik deposit) were studied usingthe methods of elementary analysis, IR-spectroscopy, scanning electron microscopy, Raman spectroscopyand X-ray phase analysis. The content of carbon in shungite rock was determined to be from 3% to 19 %.The flotation technology for shungite rocks of Kazakhstan was developed, the content of carbon in theconcentrate reaching 40.0%. When studying the elemental composition, the mineral part of shungite rockswas stated to be presented, mainly, by silicon, aluminium, calcium, magnesium, potassium, sodium, ironand titanium oxides. IR-spectroscopic investigations showed that in the concentrate, apart from polycyclichydrocarbons containing methylene groups, there appeared carboxyl groups. The results of scanningelectron microscopy (SEM) showed that flotation and thermal activation of shungite rocks on carbon allowobtaining a more developed surface structure and porosity. The structure of shungite carbon was shown bythe method of Raman scattering to be close to that of glassy carbon. The results of X-ray diffraction analysis(XRD) of natural shungite rocks showed that the samples under study contained a carbonaceous substanceand a number of mineral components: quartz, illite, bassanite, burgerite, muscovite. It is shown that shungitecarbon of “Bakyrchik” deposit is identical to shungite of Zazhogino deposit in Russia. The stated physicochemical characteristics allow to determine the directions of the use of carbon concentrate for solution of ecological and technological problems.

The European Union aims to be climate neutral by 2050. To achieve this ambitious goal, net greenhouse gas emissions must be reduced by at least 55% by 2030. Post-combustion CO₂ capture methods are essential to reduce CO₂ emissions from the chemical industry, power generation, and cement plants. To reduce CO₂, it must be captured and then stored underground or converted into other valuable products. Apromising alternative for CO₂ reduction is the use of humic acid salts (HASs). This work describes a process for the preparation of potassium (HmK) and ammonium (HmA) humic acid salts from oxidized lignite (leonardite). A detailed characterization of the obtained HASs was conducted, including elemental, granulometric, and thermogravimetric analyses, as well as 1H-NMR and IR spectroscopy. Moreover, the CO₂ absorption capacity and absorption rate of HASs were experimentally investigated. The results showed that the absorption capacity of the HASs was up to 10.9 g CO₂ per kg. The CO₂ absorption rate of 30% HmA solution was found to be similar to that of 30% MEA. Additionally, HmA solution demonstrated better efficiency in CO₂ absorption than HmK. One of the issues observed during the CO₂ absorption was foaming of the solutions, which was more noticeable with HmK.

The thermal activation of Kendyrlyk shale (at temperatures of 700–800°C) facilitates the production of a porous carbon material—activated shale. Currently available techniques such as electron...