Ultrasonic-assisted Biodiesel Production from Palm oil using adsorption of homogeneous catalysts over solid sodium silicate

Biodiesel is an alternative energy resources, which produced from transesterification of oils and alcohols using homogeneous and heterogeneous catalysts. Ultrasonic was used as pre-mixer for KOH, Na2SiO3, palm oil and methanol before increasing the reaction temperature to 60 degrees C using a water bath. All experiments were conducted at a molar ratio of methanol:oil of 6:1, reaction time of 60 min, reaction temperature of 60 degrees C and well mixing. The suspension was filtered after the end of the reaction. Purified biodiesel was obtained by water washing processes after crude biodiesel was separated from glycerol by 2 hr standing in a separating funnel. Filter solid cake was instantly used as supporter in next batch of the reaction. Effects of four variables, namely, pre-mixing period in the range of 0-10 s, number of filter cake recycle (2-4 cycles), sonicator power (10-90% of max. power of 200 watt and 20 kHz) and amount of KOH addition (0.25-0.75 g) were investigated. Response surface methodology was employed to evaluate and optimize the biodiesel production processes using Na2SiO3 adsorbed with KOH as catalyst. The design of experiment was carried out using the MINITAB RELEASE 16 and a result of 31 experiments was suggested to be made. The result showed the optimum condition of pre-mixing period of 14 s, the number of catalyst recycle to be 2 cycle, sonicator power of 36.3%and KOH addition of 0.3 g.