Biobased composite heterogeneous catalyst for biodiesel production / Intan Suraya Johari

This research focuses on addressing the higher production costs associated with biodiesel as an alternative fuel to crude oil. To overcome this challenge, biobased catalysts are proposed, derived from three different biomasses: eggshell, sawdust, and sugarcane bagasse. By utilizing these three biomasses, the limitations of a single metal catalyst can be mitigated. The objective of this study is to develop heterogeneous base catalysts for palm oil transesterification as an alternative to homogeneous counterparts. The process involves drying waste eggshell, crushing it into powder, and subjecting it to calcination at 900°C for 3 hours. Sugarcane bagasse is dried, ground into fine powder, and undergoes calcination at 550°C for 6 hours. Similarly, sawdust is dried and subjected to calcination at 550°C for 6 hours. The palm oil used in the study exhibited an acid value of 0.5 mg KOH/g, a density of 908 kg/cm3 at 26℃, and a viscosity of 65.5 mm²/s. Various catalysts, derived from calcined eggshell, sugarcane bagasse, and sawdust, were characterized using Fourier transform infrared (FTIR) analysis and Scanning Electron Microscopy (SEM). The calcined eggshell displayed a deformed spherical shape due to aggregation during calcination at 900°C, while calcined sugarcane bagasse exhibited irregular sheet-like pellets, and calcined sawdust showed stable agglomerates and irregularly accumulated particles. The elemental composition, analysed through EDX, confirmed the presence of specific components in each catalyst. The CaO-SiO2-AC catalyst, with a BET surface area of 6.5431, pore volume of 0.015918, and pore size of 9.7309, induced a colour change in phenolphthalein and 4-nitroaniline solutions, indicating strong basic sites. Optimized parameters, including a 9:1 methanol to oil molar ratio, 6 wt% catalyst loading for Batch 1, 3 wt% for Batch 2, and reaction times of 3 hours for Batch 1 and 2 hours for Batch 2, resulted in high biodiesel conversions of 82.94% and 77.10%, respectively.