ADSORPSI ASAM LEMAK BEBAS PADA MINYAK JELANTAH DENGAN TiO2/ZEOLIT ALAM

This research was conducted to determine the ability of TiO2/natural zeolite in adsorbing free fatty acids in used cooking oil. The studies included the synthesis of TiO2/natural zeolite adsorbent, characterization, and its application to adsorb free fatty acids with variations of contact time, oil volume, and adsorbent mass. The adsorbents’ functional groups were characterized by FTIR, active site by acid-base titration, and surface area by adsorption of methylene blue. The best character of adsorbent was TiO2/natural zeolite 9:100 which had a basicity active site of 11.6048 x 1020 sites/g and a surface area of ??45.6979 m2/g. The results showed that the optimum adsorption process occurred at a contact time of 60 minutes with an oil volume of 100 mL and an adsorbent mass of 0.30 grams resulting in an adsorption capacity and adsorption efficiency (%EE) of (1,00 ± 0.00) mg/g and (79.57 ± 0.17)%, respectively. The type of adsorption isotherm that occurred was Freundlich isotherm with a correlation coefficient (R2) of 0.9910 and Gibbs free energy (?G0) of -3.5571 kJ/mol, which indicated the adsorption process occurred spontaneously and it was a physical adsorption (heterogeneous and multilayers pores). Keywords: adsorption, adsorption isotherm, free fatty acids, TiO2/natural zeolite, used cooking oil.