Sulphuric acid modified biomass: A novel acid catalyst for effective esterification of free fatty acids for biodiesel production

The esterification of free fatty acids (FFA) with methanol is studied using sulphuric acid activated biomass as acid catalyst. The effects of the molar ratio of methanol to oil, reaction time and mass ratio of catalyst to oil were studied to optimize the reaction conditions. The experimental results showed that the optimum conditions were 9:1 molar ratio of methanol to oil, 2 wt % catalyst, at reaction temperature of 60°C and reaction time of 3 h. Acid value reduced from 12 to 1.9 mgKOH/g of oil. The prepared reused sulphuric acid activated biomass at least three times without loss of activity.