Аll published materials, related to the research activities od LAMAR laboratory, are dedicated on five basic fields of knowledge: 1. - Alternative energy sources, including Solid Oxide Fuel Cells (SOFC); 2. - Materials for supercapacitors and photovoltaic elements; 3. - Sensor elements for environment monitoring; 4. – Ecologically friendly advanced materials for corrosion protection, with self-healing capabilities, including thin layers and coatings and preliminary treatments and coating primers.
1. Scientific Monographs
Hydrogen Technologies and fuel cells
This Chapter comprises all basic aspects, related to the synthesis and the conversion of the hydrogen to thermal and electric energy. The literature review done is divided into: (i) theoretical bases, (ii) innovation aspects and (iii) the practical realization of alternative sources for production of hydrogen on one hand, and the alternative energy sources based on the use of this gas. Its content occupies 49 pages and contains 23 figures. The literature analysis is performed on 141 literature sources, including 16 patents. The Chapter content is divided into 10 subsequent paragraphs, dedicated on the industrial production of hydrogen from: (i) Coals and fossil fuels; (ii) By bio-conversion from biomass; (iii) by electrolysis, and also by (iv) solar and (v) nuclear energy. Because of the serious perspectives of the use of solar energy, this source is analyzed in more detail, and the respective section is subdivided into photoelectrochemical, photothermal, photobiological methods of hydrogen synthesis.
This Chapter continues with classification and detailed description of the basic types of fuel cells. After summarizing of the the basic fuel cells types, the attention is turned to the theoretical bases of the hydrogen conversion to thermal and electric energy. There a subject of special attention were the Proton Exchange Fuel Cells (PEMFC), and the Solid Oxide Fuel Cells (SOFC). The conclusive part of the Chapter is devoted to the innovation aspects and the market perspectives of the hydrogen based energetics.
Biblographic data: V. Kozhukharov, M. Machkova, Chapter 7 – Hydrogen Technologies and Fuel Cell in “Renewable Energy System: Theory, Innovations and Intelligent Applications”Edt. S. Kaplanis & E. Kaplani, NOVA Science Publ., N.Y. USA, m.June (2013) 453-501, ISBN 978-1-624177-41-5.
In the field of the high temperature methods in the nano-technologies, icluding materials recycling
High temperature methods for the synthesis and industrial production of nanomaterials
This Chapter is dedicated on the description of the basic aspects, corresponding to the high temperature synthesis of nanoparticles and nanomaterials and the impact of the applied synthesis regimes and conditions on the characteristics of the obtained products. Its content occupies 76 pages and contains 52 figures, being based on the analysis of 234 literature sources. The Chapter begins with description of the most important segments, related to the industrial production of any product, as a combination of subsequent stages for complete conversion of whatever natural of recycled material to a product with desirable properties. It includes the concepts for the correlation among the applied equipment and conditions of synthesis and the resulting conjunction among the composition, structure form and properties which should be possessed by the obtained product. The introduction part finishes with description of the four basic possible aggregate states of the inorganic matter and the respective transitions among them. There, it is clearly remarked that the liquid and solid states belong to the so called "condensed matter", due to the occurrence of clearly defined structure (i.e. spacial ordering of the elementary particles). Further, the Chapter continues with some non-conventional methods for high temperature synthesis, as follows:
(i) Explosion ignited methods for nanomaterial production, (know also as self-propagation high temperature methods of synthesis), including the production of Detonation Nano Diamonds (DND);
(ii) Plasma induced methods for nanomaterials production, which also includes wlow temperature plasma from gaseous phase and the Plasma Electrochemical Oxidation (PEO);
(iii) Spray pyrolysis methods for production of nano-sized powder materials and thin layered coatings and films, including the possible configurations of the production installations and the versatility of the application fields of the obtained products;
(iv) Laser assisted high temperature methods, including exterior and interior (in the bulk) engravement, the production of glass pearls and fibers from glass tubes;
(v) Vapor and gas phase methods for synthesis and deposition, including internal (IVPO) and external (EVPO) methods of oxidation of evaporated precursors, as well as the Fritch method for growth of metal oxide monocrystrals.
(vi) Hydrothermal and solvothermal methods for nanomaterial synthesis at high temperatures, which contains the basic components of the autoclaves and their work regime stages.
(vii) Nanomaterials synthesis via high temperature treatment of sol-gel derived materials, which summarizes the basic definitions, related to the gels, as a specific class of colloidal systems and the most important factors which predetermine the performance of the products derived from sol-gel systems.
An additional attention is turned to the versatility of this group of synthesis methods, which enables the production of Organically Modified Silicates (OrMoSil) and the Organically Modified Ceramic (OrMoCer) products. The typical advantages and disadvantages of every one group of methods as the fields of applicat5ion of the respective products are described in brief, at the end of each paragraph.
Biblographic data: S. V. Kozhukharov, (2016) High temperature methods for the synthesis and industrial production of nanomaterials PUBLISHED IN: Nanofabrication using Nanomaterials, (eds. Jean Ebothé, Waqar Ahmed), Publisher: One Central Press (OCP), Manchester (UK), ISBN (eBook): 978-1-910086-15-5
The Utilization of Waste Materials in the Glass and Ceramics Industries: Available Approaches and Technological Aspects
The continuously increasing human population and the resulting growth in customer demand, combined with the impoverishment of the natural sources of raw materials and the resulting pollution of the environment impose the need for the efficient recycling of materials in practically all branches of industry. This fact has inspired the composition of the present Chapter. It is written on 114 pages and contains 56 Figures and 12 Tables. Its content is based on 330 literature sources, predominantly from the recent years. A large part of the cited sourses is inaccessible for the English speaker readers, since their content is translated from Spanish, Portugese, Russian and Bulgarian languages. The Chapter content is subsequently divided into:
1. Introduction: It contains the basic principles, related to the forms of the existence of the matter according to its energy content: (i) plasma, (ii) gaseous, (iii) liquid, and (iv) solid. Further, it remarks that the occurrence of defined structures (as ordering of the elementary particles in the spaces occupied by the solid) is distinguishable feature of the condensed matter. Afterwareds, it describes the basic difference between the vitreous (glass) and crystalline (ceramnic) solids, remarking the possible intermediuate (polycrystalline vitroceramic) materials.
It finishes with descripttion of the conceptual bases, regarding the material production technologies, as conjunction among the used precursors, energy sources, appropriate methods and suitable equipment. Finally, it is remarked that any production process which proceeds through appropriate technological regime, as consequence of production stages and related processes.
2. Glass-Ceramics Synthesis from Agricultural Waste: It accents on the carbon based precursors, obtained from rice husks and shugarcane combustion, as well as bagasse fly ash. In addition, different compositions, like: SrO:Al2O3:SiO2:TiO2; MgO-Al2O3-SiO2 or Al2O3:MgO:Na2O:B2O3, as well as additives, such as Fe2O3, P2O5, MnO, ZnCl2 or NaCl are proposed. Besides the possibility for precise porosity control by preliminary impregnation with these activators, the beneficial effect of surfactants as dioctylphtalate or polyvinyl alcohol are mentioned, as well.
3. Advanced Ceramics Production from Fly Ash and Sewage Sludge: This paragraph begins by description of the Mg-Al-Si-O (i.e. periclase, corundum, cristobalite) system, which enables the production of pavement tiles, building bricks or water filters. It continues with examples for further enhancement of this system by addition of TiO2, La2O3, Ce, Y, and Zr. Besides a special attention is turned to the Bi-containing ceramics, showing various compositions, like Bi2Sr2Ca1-XCeXCu3Oy superconductors. Glassess with extended mechanical strength due to the simultaneous occurrence of quartz (SiO2), anorthite (CaAl2Si2O8), and hematite (Fe2O3) was mentioned, as well.
The obtaining of other phases, like norbergite (Mg3(SiO4)(F,OH)2) phlogopite (KMg3AlSi3O10(F,OH)2), sellaite (MgF2), whitlockite (Ca9P6O24), magnetite (Fe3O4), hematite (Fe2O3), augite (Ca,Na)(Mg,Fe,Al,Ti)(Si,Al)2O6 and pargasite NaCa2(Mg4Al)(Si6Al2)O22(OH)2 fractions, are mentioned, as well.
On the other hand, technological approaches as co-precipitation, and hydrothermal synthesis are also presented.
4. Production of Glass-Ceramic Materials from Thermal Power Station Waste: Since the coal fly ash from thermal power stations is also a significant potential source of glass-ceramic precursors with reliable chemical composition reproducibility, it also was object of a special interest. This paragraph begins with its multicomponent composition, which comprises: SiO2, Al2O3, CaO, Na2O, K2O, Fe2O3, TiO2, P2O5, MnO, etc. The possibility for product quality improvement by addition of B2O3, BaO, Sb2O3, V2O5 tand even Al-enriched fly ash and bauxite are mentioned, as well.
On the other hand, the production of geopolymers, based on the annealing of kaolin and the use of fly ash is remarked, as well. Exampes for use of polystyrene, AA7075 aircraft alloy wastes, plastic waste, automobile tires, residual paper pulp, residuals from fermenters and bioreactors, and urban wastewater slag, are mentioned as sources of considerable amounts of ash.
On the other hand, it is appointed that the basic disadvantage of the organic waste incineration, related to contaminants emition can be overame by further combustion in solid oxide fuel cells (SOFC), producing additional energy
5. Production of Glass-Ceramic Materials from the Metallurgical Sector: The reason for this section is that the metallurgical sector could be a remarkable source of fly ash. Indeed, potentially valuable sources of material from the metallurgical sector could be: (i) ore enrichment flotation cells; (ii) blast furnaces; (iii) electric arc furnaces; (iv) finishing surface oxide slag removal; and (v) various scrap materials, etc. This section, is divided into two part, as follows:
5.1. Production of Glass-Ceramic Materials from Aluminum Metallurgy Sector Residuals: It begins with simpe explication of the electric arc furnace function. Along with the examples, like mullite (3Al2O3.2SiO2 or 2Al2O3.SiO2), anorthite (CaAl2Si2O8), faujasite ((Na2,Ca,Mg)3.5[Al7Si17O48]·32(H2O)), sodalite Na8(Al6Si6O24)Cl2 and cancrinite- Na6Ca2[(CO3)2|Al6Si6O24]•2H2O, a special attention is turned to the zeolites as a special class of geopolymers. On the other hand, alternative methods, like isostatic pressing, and the sol-gel method are given. The versatility of the sol-gel method is remarked by examples for its recent applications for synthesis of: corrosion protective coatings, sensor element materials, catalysis and photocatalysis for environmental applications alternative energy source components, optical materials, selective membranes, environment remediation, medical applications, etc.
This section finishes with utilization of SO3, from sintering of gibsum, for sulfuric acid production.
5.2. Utilization of Waste from the Iron and Steel Industrial Sector: The steel industry is a considerable producer of iron and other metals containing minerals (generally oxides) which can be successfully applied in the glass and ceramic industry. After brief description of ythe blast furnace function, this section renders examples, like magnetite (Fe3O4), fayalite (Fe2SiO4), and pyroxene (i.e., partially substituted aluminosilicates), devitrite (Na2Ca3Si6O16), cristobalite (SiO2), or hematite (Fe2O3), as potential precursors.
6. Recycling of Glass-Ceramic Industrial Residuals: This section describes the possibilities to use glass/ceramic wastes or unclassified production in the glass and ceramic plants. It describes some classical methods as ball-milling and even production of nano-particles by disk-milling, as well as some alternative approaches, lile glass pearl production from waste glass fusion spraying. The possibilities for fine size fraction separation by hydrocyclones and spray drying are also shown. Exampes for highly porous decorative glass bricks are given, as well. The color control by addition of Ca (white), Co (blue), Cr (green), and Fe (red) compounds is mentioned.
7. Glass-Ceramic Materials from Spent Catalysts: Especial attention is turnmed to the utilization of catalysts from petrol refineries. A multitude of possible compositions, like: Mg2TiO4, Zn2TiO4, Co2TiO4, Ni2TiO4, Cu2TiO4; MgAl2O4, Mg3CeO4, MgCr1.2Al0.4Fe0.4O4, MgCr1.6Al0.4O4, MgAl2О4, MgCr2О4, FeCr2О4, FeFe2О4, as well as (Mg, Fe)(Al, Ti, Cr, Fe)2О4 solid solutions are given as examples for ceramic pigments from wasted catalysts. Especial attention is turned on the CIE L*, *a, b* and RGB color evaluation systems, because of their importance for pigment characterization.
The Chapter concludes with brief concepts, remarked in the Chapter, remarking the variety of possible waste products as potential precursors for the glass and ceramic industrial branches.
Bibliographic data: Stephan Kozhukharov, Tzvetan Dimitrov, Ester Barrachina Albert, Iván Calvet Roures, Diego Fraga Chiva and Juan Bautísta Carda Castelló, The Utilization of Waste Materials in the Glass and Ceramics Industries: Available Approaches and Technological Aspects, PUBLISHED IN: Recycling and Reuse of Materials, Marcus Holst, and Tilde Kjeldsen, Eds.; NOVA Sci. Publ. (2018) pp. 101-166; ISBN: 978-1-53613-466-4
Spray Pyrolysis as a Versatile Method for Advanced Materials Production. Basic Concepts and Available Applications
This Chapter is devoted to the literature analysis of the actual trends in the field of the industrial Spray Pyrolysis (SP) methods, the basic requirements of the respective equipment and the variety of the possible SP derived materials. It is written on 165 pages and contains 21 figures 1 table and 255 references. It is dedicated on the basic terminology and principles, related to the spray pyrolysis as industrial technological method. The Chapter content is divided into several sections, subsequently connected among themselves. The Chapter begins with the basic definitions, related with the SPS-synthesis of nano-particles and the SPD-deposition of thin layers and coatings, distinguishing them from the rest spray based methods, like spray freezing, spray drying, etc. Further, the description of the respective production stages and processes is assisted by examples from the real industrial practice. Afterwards, the basic types of spray formation units are described, remarking the principle difference among the nozzles, pluverizers, nebulbulizers, injectors and atomizers. In addition, tghe conventional SP techniques are compared with Flame Assisted (FASP) and the Plasma Assisted (PASP) methods, in accordance with the type of the high temperature cameras. The description of the basic operation units is completed by examples of entire SP industrial production installations, working at continuous regime. The explications inside the text are based on real examples of production of bismuth ferrite, barium titanate, indium tin oxide and carbon nanotubes. The SP production of these materials was chosen, because of their exceptional magnetic, photocatalytic, and opto-electric properties. The versatility of the SP derived products is described, as well, mentioning the fields their potential application, as:
(i) Automatics (for instance sensors and detectors)
(ii) Optoelectronics and microelectronics (semiconductor and superconductor layers and particles).
(iii) Alternative Energy Sources (photovoltaic elements, fuel cell components, water splitting devices, supercapacitors, lithium-ion and Zn-air batteries, etc).
(iv) Catalysts and Photocatalysts (remarking their importance so for the organic chemical synthesis, so for pollutant decomposition).
(v) Adsorptive and membrane filters (for environmental and house hold applications).
(vi) Materials for disinfection, etc. Besides, some alternative spray based methods, like for instance: Spray Freezing (SF), Spray Drying (SD) fusion pluverisation (FS) and the и InkJet method are described, as well.
The Chapter comprises all the aspects, corresponding to the specific features of the SP based methods, the distinguishable features of the respective products, at their fields of application. The aim of its composition is to be a valuable tool so for lecture courses, so as a practical manual for the experts in this field.
Bibliographic data: S. Kozhukharov, V. Zhelev, S. Tchaoushev, Chapter 3: Spray Pyrolysis as a Versatile Method for Advanced Materials Production. Basic Concepts and Available Applications, Publisdhed in: Advances in Materials Science Research Vol. 37, Maryann Wythers Ed.; NOVA Sci. Publ. (2019) pp. 101-166; ISBN: 978-1-53615-038-4