Research Article

Processing of high-grade zeolite nanocomposites from solid fuel combustion by-products as critical raw materials substitutes

¹ Technical University of Sofia, Sofa, Bulgaria
² Institute of Organic Chemistry with Centre of Phytochemistry, BAS, Sofia, Bulgaria
³ Institute of Optical Materials and Technologies “Acad. J. Malinowski”, BAS, Sofia, Bulgaria
⁴ Institute of Nanostructure Technologies and Analytics, University of Kassel, Kassel, Germany

^* e-mail: sboycheva@tu-sofia.bg

Received: 7 December 2019
Accepted: 28 May 2020

Abstract

High-grade zeolite nanocomposites are synthesized utilizing solid by-products from combustion of coal for energy production in Thermal Power Plants applying alkaline aging, hydrothermal and fusion-hydrothermal activation procedures. The obtained coal ash zeolites were studied with respect to their chemical and phase composition, morphology, surface parameters and thermal properties. It was found that they are distinguished in nanocrystalline morphology and significant content of iron oxide nanoparticles (γ-Fe₂O₃, α-Fe₂O₃, γ-Fe₃O₄) and doping elements (Cu, Co, Mn, V, W, etc.) transferred from the raw coal ash, and therefore they are assumed as nanocomposites. Coal fly ash zeolite nanocomposites are characterized by a mixed micro-mesoporous texture, significant concentration of acidic Brønsted centers due to their high surface insaturation, high chemical and thermal stabilty. This unique combination of compositional and textural properties predetermines the application of these materials as catalysts for thermal oxidation processes, anticorrosion barrier coatings, carbon capture adsorbents, matrices for hosting functional groups, detergents etc. Examples for coal fly ash zeolite applications for substitution of critical raw materials in practice are provided.