Akbar Dauletbay’s research while affiliated with Al-Farabi Kazakh National University and other places

Humic substances (HSs) are a diverse class of natural compounds with no fixed chemical composition, formed from plant and microbial residues through the action of environmental factors and living organisms over many years. Despite extensive research spanning two centuries, the complex and variable nature of HSs' structure remains a subject of scientific inquiry. These substances, notably humic acids, fulvic acids, and humin, play crucial roles in ecological and environmental processes due to their abundant functional groups and resilience to biodegradation. This review explores the intricate structure and properties of HSs, their classification, and their occurrence in nature. It highlights the different models proposed to describe the structural fragments of humic acids, emphasizing their aromatic cores and diverse functional groups. The variability in the molecular weight distribution of HSs, attributed to their polydisperse nature, is also discussed, along with methods used for their determination, such as exclusion chromatography. Furthermore, the elemental and functional compositions of humic acids are examined, detailing their acid-base properties and capacity for heavy metal complexation. The synthesis of HSs from natural sources, such as soil, peat, coal, and artificial processes, is covered, showcasing methods like alkaline extraction and hydrothermal treatment. Recent advancements in artificial humification, including oxidative ammonolysis and Fenton reagent-based oxidation, are reviewed for their potential in producing environmentally friendly humic materials from lignin and waste biomass. The study concludes by underscoring the environmental significance and practical applications of HSs, particularly in agriculture, soil conditioning, and environmental remediation. The diverse properties and synthesis methods of HSs make them promising candidates for sustainable material production and environmental management. Humic acids are versatile compounds beneficial for human health due to their potent antioxidant properties, immune-modulating effects, and support for gastrointestinal health and detoxification. Structurally diverse, they feature groups like carboxyl, phenolic hydroxyl, quinones, ketonic carbonyls, amino, and sulfhydryl, contributing to their stability and amphiphilic nature. In pharmaceutical applications, they show promise for drug delivery, antioxidant therapies, wound healing, antimicrobial actions, and biofilm disruption, underlining their biocompatibility and safety. Key words:

For large-scale hydrogen use for alternative fuel problems, hydrogen transportation must be solved. Hydrogen can be transported as compressed gas, liquid, or bound in carriers. The chapter describes current transportation technologies—gaseous hydrogen via pipelines or special trucks, and liquid hydrogen in cryogenic tanks. The potential of using existing natural gas pipelines is analyzed; the need for modern pipeline material complex research is emphasized. Transportation in solid or liquid carriers, disadvantages and advantages of transportation methods, and problems and ways to solve them are analyzed. Hydrogen facilitates the conversion of low-grade crude oils into high-energy transport fuels by catalytic cracking and desulfurization. Ammonia production, essential for fertilizers and explosives, relies heavily on hydrogen synthesis from nitrogen and hydrogen. Methanol and dimethyl ether fuels offer alternatives to hydrogen storage and transportation, while liquid hydrocarbon fuels from coal and biomass utilize hydrogen in conversion processes like Fischer-Tropsch. Proton exchange membrane and alkaline fuel cells depend on hydrogen for electricity generation in transportation. Additionally, hydrogen serves as a reductant in metallurgy, with advancements in direct iron reduction and green steel initiatives driving sustainable practices in the steel industry. These applications underscore in modern processes and its potential for addressing energy and environmental challenges.

This work describes the production of nanocellulose by removing lignin from biomass by the peroxide method in the presence of an H2SO4 catalyst and the study of its physicochemical properties. The structure of cellulose and modified nanocellulose was studied using Raman spectroscopy, IR (infrared) spectroscopy, X-ray diffraction, and SEM (scanning electron microscopy). The resulting increase in the crystallinity of NFC (nanofibrous cellulose) was confirmed by X-ray diffraction analysis. This indicates that cellulose was associated with the removal of amorphous parts. As a result of X-ray diffraction, overlap on NFC radiographs occurred even in the area of intense lines. In the sample obtained by IR spectroscopy, the presence of groups (3413.12 cm ⁻¹ ; 2918.34 cm ⁻¹ ; 1373.30 cm ⁻¹ ; 617.52 cm ⁻¹ ) corresponding to the nature of NFC was detected. Strong absorption at 1429.8 cm−1 in the spectrum of CMC (carboxylmethylcellulose) revealed –COOH groups, indicating successful carboxylation of cellulose. The morphological surface, average particle size and structure of the samples were studied. As a result of a comparative analysis of morphological structures, an ordered filamentous structure of nanofibrous cellulose characteristic of fibers and a porous structure of CMC with a modified surface and uneven fibers were revealed. The developed method for producing modified cellulose from biomass does not require multi-stage processing compared to traditional methods and is safe for the environment. It has been shown that it is possible to obtain high-quality cellulose in one stage without the use of reagents containing sulfur and chlorine, high pressure and high water consumption.

The quantum-chemical method is a crucial area of innovation for photodynamic therapy. Density Functional Theory can be used to investigate the electronic structures, excited states, and other photochemical properties of a photosensitizer. In the present study, the intensities and energies of electronic transitions are calculated, and absorption and vibrational spectra of two photosensitizers, protoporphyrin IX and pyropheophorbide-a are simulated. The calculation proved the experimental results of the fact that pyropheophorbide-a exhibits the intense absorption of Qx at longer wavelength than protoporphyrin IX, and absorption intensity is higher than protoporphyrin IX. Additionally, the influence of solvent models on IR-spectra calculation is studied. This study can lead to the design of new photosensitizers to improve PDT efficiency.