Temenuzhka Hristova Radoykova

Temenuzhka Hristova Radoykova
University of Chemical Technology and Metallurgy | UCTM · Central Research Laboratory

PhD

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17
Publications
4,307
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153
Citations
Citations since 2017
4 Research Items
83 Citations
2017201820192020202120222023051015
2017201820192020202120222023051015
2017201820192020202120222023051015
2017201820192020202120222023051015
Introduction
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Publications

Publications (17)
Article
Full-text available
Activated carbons were prepared based on hydrolyzed lignocellulosic biomass, and were chemically activated with potassium hydroxide and phosphoric acid. The texture parameters of the adsorbents obtained were determined by low-temperature nitrogen adsorption; their thermal stability was studied by DTA/ TG and the surface functional groups-by FTIR sp...
Article
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Hydrolyzed plant biomass from willow, paulownia and straw was studied by using XPS and IR spectroscopy method in order to understand in depth their chemical composition and the nature of the functional groups on their surfaces. The surface concentration and the presence or absence of some functional groups and their amount on the surface of these m...
Article
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ABSTRACT The purpose of this work was to investigate the possibility of wood preservation by its modification with different substances through the penetration method and to study the impact of the process on some operational properties of the wood material. The experiments were conducted with poplar wood (samples 10x1x1 cm), which has low density...
Article
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In the present work, the adsorption of Ag+ ions on hydrolyzed plant biomass (willow, paulownia, wheat straw and maize stalks) was investigated. Chemical analyses were performed to establish the composition of the obtained materials. Adsorption mechanism, adsorption sites and specific surface areas of these materials were examined by BET analysis, I...
Article
Full-text available
Materials with a high specific surface area (329-621 m2/g) were synthesized by modification of blast furnace slag. The process included chemical and thermal treatment. Four samples were obtained as the chemical treatment was conducted at various values of pH. ICP-OES, XRD, FTIR, SEM, BET-analysis and other methods were applied for phase and structu...
Article
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Lignin-based low-molecular phenol compounds produced by alkaline hydrolysis of vegetable biomass poplar wood and poplar bark - can be used to increase the chemical stability of automobile petrol fuels. The comparative kinetic analysis of alkaline hydrolysis of both types of poplar biomass outlines the effect of the process duration and NaOH concent...
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The effect of autoclaving of the granulated blast furnace slag on its catalytic activity with regard to the oxidation of CO was investigated. The results show that autoclaving after chemical treatment of slag with nitric acid or nitric acid and ammonia, leads to the increase in the specific surface area, but reduces the concentration of catalytical...
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The adsorption of Mn2+ ions from samples of hydrolysed lignocellulosic materials (HL) and alkaline-treated hydrolysed lignin (AAHL), obtained from paulownia, heat straw and maize stalks was investigated in this article. The adsorption mechanism, adsorption sites specific surface and the potential for practical application of these materials were ex...
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The ability to create new active catalysts for complete oxidation of carbon monoxide and organic compounds on the basis of the metallurgical slag for waste gas purification was proven. The procedure for the synthesis of the catalysts includes only acid and thermal activation of the metallurgical slag, during which in addition to increasing the cata...
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By extraction with toluene and ethyl acetate monomeric lignin compounds: 2-methoxyphenol, 2,6-dimethoxyphenol, 4-hydroxy-3-methoxybenzaldehyde, 4-hydroxy-3,5-dimethoxybenzaldehyde, 1-(4-hydroxy-3-methoxyphenyl) ethanone, 1-(4-hydroxy-3,5-dimethoxyphenyl) ethanone, etc. were isolated from black liquor and sulfate lignin, and identified through GC/MS...
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Modern chemical industry is based on natural energy sources - coal, petroleum and natural gas, which have been formed by decomposition of vegetable materials in the course of millions of years. As their reserves are limited and gradually exhausted, one of the main tasks of the industry is to provide the complete, versatile and most effective utiliz...
Article
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The oxidation stability of gasoline and lubricating materials is one of their most important service properties. Additives are used for improvement of chemical stability, the phenolic antioxidants being one of the most effective. In this paper phenolic compounds produced by alkaline destruction of poplar wood bark are used as antioxidants. The phen...
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Aqueous alkaline depolymerization of technical hydrolysis lignin (THL) was carried out with a 5% NaOH solution at a temperature of 180°C for 6 hours, the ratio between the biomass and depolymerizing agent being 1:8. The poplar wood sawdust was treated under the same conditions for 2 hours, where anthraquinone was added as a catalyst (0.5 wt %). The...
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The difficulties of lignin structure determination by universal analytic methods impose new disparate approaches to put together and substantiate the experimentally gathered data. Elaborated computer models and fragments of the lignin molecule are largely utilized in computational chemistry. Prediction of the conformations and spatial structures of...
Article
Full-text available
Alkaline destruction of technical hydrolysis lignin (THL) has been performed under different conditions (treatment duration - 2, 4 and 6 hours, NaOH concentration - 3, 5 and 7%, lignin:NaOH solution ratio (hydromodule - h.m.) - 1:6; 1:8; 1:10), and was followed by the extraction and the identification of obtained compounds. Process temperature - 18...

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