Persiapan Katalis Dari Tanah Pemucat Bekas Untuk Sintesis Biodiesel

Abstract

Spent bleaching earth (SBE) on this research is a waste generated from the palm oil refining process in the cooking oil or oleochemical industry. SBE can be applied as a catalyst buffer for biodiesel synthesis. However, the use of SBE as a catalyst buffer needs to be regenerated first, because the pores in the SBE have been clogged due to being covered by oil. Removal of oil and impurities can be done by Microwave Assisted Extraction (MAE). This extraction process was carried out with several solvents: hexane, methanol, acetone and hexane: methanol (1:1), variations in the ratio of SBE to solvents 1:4, 1:5 and 1:6, at 100, 180, and 300 watts of power and extraction time of 50, 70 and 80 minutes. The best extraction process was obtained using hexane solvent at a power of 300 watt, a ratio of SBE to solvent of 1:5 and an extraction time of 80 minutes with the resulting oil yield of 20,97%. The characteristics of the residual oil produced by FFA, moisture, IV, DOBI, PV were 10,91%, 1,52%, 56,71 gr I2/100 gr, 1,372, and 7,419 meq/Kg, respectively. Furthermore, the RSBE obtained was calcined at a temperature of 500 °C for 5 hours using a furnace to remove impurities. After that, it was impregnated with 15, 20, and 25% KOH solution with a ratio of RSBE to KOH solution (1:20) at a stirring speed of 300 rpm, temperature of 60 °C for 8 hours. Then it was dried in an oven at 110 °C for 12 hours, and re-calcined at 500 °C for 5 hours to make the potassium metal bond and RSBE stronger. The best RSBE impregnation was produced using a 20% KOH solution with a potassium content of 1,41%, surface area 19,5168 m2/gr, and pore volume 4,8 mm3/gr. KOH impregnated RSBE at the best conditions was applied as a catalyst in the palm oil transesterification process (RBDPO) with %catalyst variables 2,3,4 and 5% and a molar ratio of oil to methanol 1:7, 1:9, 1:11, 1:13, 1:15. The best biodiesel yield was 93,06% using 5% catalyst and 1:11 molar ratio of oil to methanol.