Scientific publications
Materials (Q1). - (published on December 27, 2022) - T. 16. - P. 264.
Influence of Various Coal Energy Wastes and Foaming Agents on Foamed Geopolymer Materials’ Synthesis
E.A. Yatsenko, B.M. Goltsman, S.V. Trofimov, Y.V. Novikov, V.A. Smoliy, A.V. Ryabova, L.V. Klimova
The regularities of obtaining foamed alkali-activated geopolymer materials based on different wastes of coal power engineering (fly ash, fuel (boiler) slag, ash, and slag mixture) were considered. The phase composition of the studied waste showed the presence of a significant amount of the amorphous phase, as well as a crystalline phase. mostly in the form of high quartz. The microstructure of studied the waste showed that the fly ash consisted of monodisperse hollow aluminosilicate microspheres, the fuel slag was represented by polydisperse irregular particles, and the ash and slag mixture included both of these materials in different ratios. Blowing agents such as aluminum powder, hydrogen peroxide, and sodium hypochlorite were chosen to achieve the porous structure of the geopolymer materials. The calculations of the geopolymer precursor compositions were carried out. Samples were synthesized, and their physical and mechanical properties, such as density, strength, porosity, and thermal conductivity, were analyzed. The micro- and macrostructure of the samples, as well as the pore distribution of the obtained geopolymers were studied. Conclusions were made on the choice of the most-optimal foaming agent and the optimal coal combustion waste suitable for the synthesis of the geopolymer materials.
Read full articleJournal of Cleaner Production (Q1), 375, 134083. DOI: 10.1016/j.jclepro.2022.134083.
Polyethylene terephthalate (PET) waste plastic as natural aggregate replacement in geopolymer mortar production (2022)
Lazorenko G., Kasprzhitskii A., Fini E.H.
This work investigates the recycling potential of polyethylene terephthalate (PET) bottle wastes as natural sand substitute in geopolymer (GP) mixtures to reduce plastic pollution and transition to a circular economy. Fresh and hardened properties of coal fly ash-based GP mortars with replacement of quartz sand by grinded fine PET particles of 0.315–1.25 mm in size (20%, 40%, 60%, 80% and 100%) were evaluated. It was found out that an increase in plastic aggregate content leads to a decrease in compressive strength and flexural strength of geopolymer mortars. In turn, the splitting tensile strength increased slightly when up to 40% of the sand volume was replaced by plastic aggregate. At this replacement level, the fresh geopolymer mixes had workability close to that of conventional mortar. The flake-like PET particles contributed to the reduction of cracking of the specimens and more ductile failure modes. Furthermore, GP mortars containing recycled PET bottle wastes at the full replacement level of natural aggregate showed advantages in lightweight (up to 15%), water absorption (up to 26%) and thermal insulation properties (up to 59%), enabling production of sustainable construction materials with environmental and economic benefits.
Read full articleCeramics International (Q1), 48 (24), pp. 37464 - 37469. DOI: 10.1016/j.ceramint.2022.08.114.
Grand canonical Monte Carlo simulation study on the effect of crystallinity and structural disorder on water sorption in geopolymers (2022)
Lazorenko G., Kasprzhitskii A.
A comparative study on water sorption by different components of the binder phase formed in geopolymerization was performed using the Grand Canonical Monte Carlo (GCMC) simulation method. Water sorption isotherms for crystalline, defective and amorphous model structures with Na+ exchangeable cations at temperatures of 298 K were obtained. The isosteric heats of adsorption of water in each structure were calculated. In addition, the distribution pattern of H2O molecules in the researched frameworks and the preferred sorption sites were also investigated. The GCMC results showed that the structural changes in the host framework significantly affect water sorption properties, leading to changes in water sorption capacity and nature of interactions with guest water molecules. The GCMC simulation results have provided useful information on the behavior of water confined in geopolymeric binder phase, which is difficult to observe experimentally, contributing to a better understanding of the mechanism of water adsorption in geopolymer-zeolite hybrid materials.
Read full articleInternational Journal of Hydrogen Energy (Q1), Volume 47, Issue 97, 2022, Pages 41046-41054.
Review on modern ways of insulation of reservoirs for liquid hydrogen storage
E.A. Yatsenko, B.M. Goltsman, Y.V. Novikov, A.I. Izvarin, I.V. Rusakevich
Modern ways of developing hydrogen energy as an alternative energy source have been established. The description of hydrogen storage methods in various systems is given: in pressurized cylinders; in the adsorbed state using carbon nanotubes as an adsorbent; in the form of hydrides; in a chemically bound state in the form of methane and ammonia; in tanks at low temperatures. The last method of hydrogen storage is chosen as the most optimal one. The design of tanks for storing hydrogen at low temperatures has been studied. The use of spherical tanks with a heat-insulating layer makes it possible to store large reserves of hydrogen. The main insulation technologies for storing liquid hydrogen are considered: active thermal insulation and passive thermal insulation. Possible heat-insulating materials and operational requirements for them are given. The most promising heat-insulating materials for cryogenic tanks are porous inorganic fillers. The expediency of using foam glass as a heat-insulating material for hydrogen storage has been established. Foam glass has a number of advantages over similar insulating materials, such as water and vapor impermeability, frost resistance, chemical and thermal stability, and high mechanical properties. Methods for obtaining ultralight foam glasses with a density of not more than 150 kg/m3 are presented. To do this, it is advisable to use glass production waste, coal generation waste, broken glass for various industrial and domestic purposes, since the production of foam glass based on specially obtained glass significantly increases the cost of this heat-insulating material. The mechanisms of glass mass foaming with the use of solid and liquid foaming agents are considered.
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