Browsing by Author "Serafimova E."

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    INTEGRATED TREATMENT OF BIO-WASTES FOR CIRCULAR ECONOMY
    (2021-01-01) Serafimova E.; Petkova V.
    This work deals with the development of a procedure for the isolation of a complex of biologically active substances from the aerial parts of some plants of Polygonum L. grown up in Kazakhstan and the determination of a possibility of their application to officinal medicine. The effect of various factors (the temperature, the extraction time, the raw material: solvent ratio) on the chemical composition of the extracts of a high yield of biologically active substances from Polygonum minus, P. aviculare, P. hydropiper is studied.
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    Investigation of long time stored propellants
    (2014-01-01) Nedkova M.; Shishkov P.; Serafimova E.; Dishovsky N.
    An investigation of double based propellants and pyroxiline, produced before the year 2000 was carried out. The process of ageing during long time storage of single and double-based propellants and pyroxilin in non heated military stores and in heated building at room temperature was studied by elemental analysis (EA). The velocities of burning were measured by DSC and the decomposition energy of the propellants was calculated. Obtaining of a shift of the bands, con-nected by hydrogen bonds formation between the obtained-OH groups at the place of-ONO2 groups after ageing was confirmed by FTIR spectroscopy.
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    INVESTIGATION OF WASTE BIOMASS ASH FROM PAPER INDUSTRY
    (2024-01-01) Serafimova E.; Manoylova A.; Stoyanova V.
    The main part of companies in Bulgaria are built, however in the 70s, and upgraded last decade. The country supplies around 80 % of its supplies of paper, paperboard and pulp with own production. Integrated treatment of wastes is a priority for realizing closed life cycle of materials. The aim of the present work is to investigate the composition and other important characteristics of biomass wood ash wasted from paper industry. The correlations and associations among the chemical characteristics are also studied to find some basic trends and important relationships between two similar wastes from different enterprises. It was proved that all samples taken contained Ba, Cr, Mn, Ni, Co, Al, Fe, Cu and Zn far below the legal limits for such type of products. A product has a certain anti-acidic effect. The other positive result was that the content of iron is between 34 to 60 mg per 1 kg dry waste. The microscopic photos confirmed that the particles are close to the nano-size materials. The content of the elements C, N, H is in good quantities and ratios, which is a prerequisite for their use as a soil improver. By the results of this study, it was confirmed that all samples produced as a result of the thermal treatment and final low water content achieved are free from pathogen microorganisms and different weed seeds, affecting the yield and soil sustainability. That allows determining the optimal ratio between the used components with a view to obtain products with desired thermal stability and physico-chemical properties as soil improvers.
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    THE POTENTIAL FOR CARBON SEQUESTRATION IN RECLAIMED MINE SOIL
    (2024-01-01) Serafimova E.; Dedelyanova K.
    Mining sector has been the central attention of the business and public policy sustainable development scheme for several years. Reclamation territories are with potential carbon sequestration capacity in degraded mining areas and can be an impeccable option for achieving sustainable development goal-13. This paper made an investigation about the presence of heavy metals in reclaimed area possibilities to improve reclaimed soils with biochar with idea to enhance ecosystem carbon pool and atmospheric CO2 sequestration capacity to offset CO2 emission and soil organic carbon losses. The results show that the carbon content in biochar is 46.6 % and would be classified in class 2 according to the International Biochar Initiative. H/C and O/C atomic ratios could be useful for restoration of degraded poor mine soils through enhanced carbon sequestration. O/C ratio is 0.085 mol mol–1 and half-life of biochar is 2795.65 years, which confirm the biochar stability. For each kilogram of biochar incorporated into the soil, 144 g of carbon were sequestrated 52, 8 % CO2 emission reduction. Hence, the biochar developed in this study can be used in carbon-deficient soils with the added benefit of long-term carbon storage.