Biodiesel production via esterification of oleic acid as a representative of free fatty acid using electrolysis technique as a novel approach: Non-catalytic and catalytic conversion

Abstract In the present study, production of biodiesel from biomass containing free fatty acids has been evaluated through electrolysis method as a novel efficient technique, in absence and presence of alkaline and acidic catalysts at mild operating condition. The impact of operating parameters such as voltage (10−30 V/cm), reaction time (1−3 h), methanol to oil molar ratio (10:1−40:1), acetone to methanol molar ratio (0:1−0.5:1), NaCl concentration (0−0.045 M) and catalyst type and loading on the process performance have been investigated in term of biodiesel production yield. The achieved results indicate that the biodiesel production yield using electrolysis method is about 42 % at voltage of 20 V/cm, reaction time of 2 h, NaCl concentration of 0.015 M, methanol to oil molar ratio of 20:1, acetone to methanol molar ratio of 0.25:1 and without presence of catalyst, whereas it is improved to 52 % and 95 % in the presence of 5.6 wt.% of KOH and 13 wt.% of H2SO4 as catalyst, respectively. The determined physicochemical properties of the synthesized biodiesel via electrolysis method incorporating density, kinematic viscosity, cetane index, Iodine value and cloud point properties satisfy the main fuel standard criteria. The cetane index of synthesized biodiesel using electrolysis method is 57.3.