A bentonite catalyst was prepared using acid-treated bentonite modified by calcium hydroxide and sodium hydroxide with wet method

and it was applied in the transesterification of jatropha oil with methanol to form biodiesel. Firstly

the kinetics of this transesterification reaction was studied in the temperature range of 323.15—338.15 K after eliminating both inner and outer diffusion effects. Then

the crude biodiesel from the transesterification was purified using the adsorption of natural bentonite at room temperature

and the effects of bentonite dosage as well as adsorption time on the removal of free glycerin were investigated. The results showed that the conversion of jatropha oil to biodiesel on the prepared catalyst reached 96.7% under the optimized conditions. And the transesterification can be well described using the pseudo-first-order kinetic model with the activation energy of 67.87 kJ·mol-1. The purified product could meet the requirements of European Standard for biodiesel fuel (EN 14214) with the yield of biodiesel over 96%

when the purification process was performed with a bentonite dosage of 3% (mass) and reaction time of 30 min.