Mesoporous Bifunctional K₂O Catalyst Using Chitosan Template for Biodiesel Production

¹ Department of Chemistry, Faculty of Science, Universiti Teknologi Malaysia, 81310 UTM Skudai, Johor, Malaysia
² UNISZA Science and Medicine Foundation Centre, Universiti Sultan Zainal Abidin, Besut Campus, 22200 Besut Terengganu, Malaysia

^* Corresponding author: susilawatitoemen@utm.my

Abstract

Mesoporous metal oxides are highly effective catalysts for biodiesel production due to their large surface area and adjustable pore structures, which enhance mass transfer and catalytic activity. In this study, a mesoporous K₂O catalyst was prepared using chitosan, a natural polymer, as a template. Chitosan was first dissolved in a mild acetic acid solution and mixed with potassium nitrate at an optimized ratio. The mixture was stirred and then added dropwise into a sodium hydroxide solution, inducing the formation of solid spherical beads through chemical bonding. The beads were then dried, and calcined at 700 °C for 2 h. This calcination step removed the organic chitosan, creating a porous structure, while converting potassium compounds into active catalytic species including K₂O, K₂O₂, and K₂CO₃·1.5H₂O, which also helped maintain the bead morphology. SEM analysis revealed a dense, porous structure, while the catalyst’s bifunctional nature was confirmed by a total basicity of 1.346 mmol/g and total acidity of 1.515 mmol/g. The optimised synthesis conditions yielded a maximum biodiesel yield of 95.26%, demonstrating the catalyst’s potential for efficient biodiesel production.