Synthesis and Characterization of Potent Catalysts for Production of Biokerosene

Abstract

The increasing demand for sustainable aviation fuels has stimulated interest in the 
development of low-cost and environmentally friendly catalysts derived from renewable waste 
resources. This study investigates the synthesis and physicochemical characterization of 
heterogeneous catalysts produced from two abundant agricultural waste materials, rice husk 
and eggshell, for potential application in the catalytic upgrading of bio-oil to bio-kerosene. 
Rice husk and eggshell samples were collected locally and subjected to a series of pre
treatment processes, including washing, drying, grinding, and calcination, to produce silica 
(SiO₂) and calcium oxide (CaO)-based catalysts, respectively. Comprehensive catalyst 
characterization was carried out using Fourier Transform Infrared Spectroscopy (FTIR), X
ray Fluorescence (XRF), X-ray Diffraction (XRD), Thermogravimetric Analysis (TGA), and 
Brunauer–Emmett–Teller (BET) surface area analysis. BET results revealed that the rice 
husk-derived catalyst possessed a specific surface area of 282.1 m² g⁻¹, whereas the 
eggshell-derived catalyst exhibited a significantly higher surface area of 726.2 m² g⁻¹. Both 
catalysts displayed mesoporous pore structures, indicating favourable textural properties for 
catalytic applications involving large organic molecules. FTIR analysis identified characteristic 
absorption bands at approximately 3000 cm⁻¹, 1050–1100 cm⁻¹, and 2800–2950 cm⁻¹, 
corresponding to O–H stretching vibrations associated with adsorbed moisture, Si–O–Si 
vibrations characteristic of silica, and C–H vibrations associated with calcium oxide-based 
materials, respectively. XRF analysis confirmed the dominance of silica (86.6 wt.%) in the rice 
husk catalyst and calcium oxide (89 wt.%) in the eggshell catalyst. XRD patterns revealed the 
presence of both crystalline and amorphous phases, while TGA results demonstrated 
excellent thermal stability for both catalysts beyond 500°C. The study therefore confirms 
the successful synthesis of highly active and thermally stable heterogeneous catalysts from 
rice husk and eggshell wastes, highlighting their potential application in the conversion and 
upgrading of bio-oil into bio-kerosene and other sustainable biofuels.