bentonite, as a natural zeolite enhanced biodiesel production through trans-esterification of waste oil

waste oils are becoming increasingly more important as feedstock for the production of fuels and chemicals. the influence of bentonite on the koh-catalyzed methanolysis of waste cooking oil was investigated. it was found that an appropriate introduction of bentonite can promote the methanolysis. by the rapidly removal of the water from the system, bentonite enhances the transformation of koh to the catalytically active methoxide species. further, the main side reactions are significantly inhibited. the methanolysis of triglycerides took place in the liquid phase rather than in the solid phase. the introduction of bentonite also lowered the soap concentration in crude biodiesel, which was beneficial for the posttreatment to generate refined biodiesel.