Hydrothermal Conversion of Fly Ash into Monomineralic Zeolite Synthesis for Biodiesel Production

Fly ashes as a residue from combustion processes of coal in coal-fired power stations can be applied for zeolite formation. The zeolite synthesis has considerable effect on their structure following further catalytic use. The formation of analcime is guided by the operation of the silicate framework in the company of Na⁺, [Al(OH)4]⁻, [H2SiO4]²⁻ species, coming from fly ash processing. Here, we have highlighted the importance of conducting the coal fly ash waste management towards monomineralic zeolite synthesis, in the form of powder analcime. It is the first report on powder analcime production without fly ash residues, confirmed by SEM and XRD analysis. The obtained analcime-zeolite was further explored as biodiesel catalyst based on base-catalyzed transesterification process. The effect of analcime catalyst usage on the biodiesel yield was determined with observed 97.2 % conversion efficiency under the concentration of 4%wt at 230 °C, with three times reusable analcime catalysts. Coal fly ash-derived monominerals on a large scale can significantly contribute to the sustainability goals and efficient waste management.