Insight into the catalytic conversion of palm oil into biodiesel using Na+/K+ trapped muscovite/phillipsite composite as a novel catalyst: Effect of ultrasonic irradiation and mechanism

A novel composite of muscovite/synthetic zeolite (phillipsite) (Mu/Pz) was synthesized in an open system by the alkaline modification at 150 °C under stirring of speed 600 rpm for 22 h. The composite was characterized as a novel, low cost and effective basic catalyst in the transesterification conversion of palm oil into biodiesel. The catalytic properties of Mu/PZ were studied based on several controlling factors by normal stirring and ultrasonic irradiation as mixing techniques. The maximum biodiesel yield obtained by normal stirring is 94% and was accomplished after adjusting the controlling factors at 180 min as conversion interval, 20:1 as the incorporated methanol-to-oil molar ratio, 100 °C as reaction temperature, 5 wt, % as a Mu/Pz loading and 1300 rpm as a stirring speed. The influence of ultrasonic irradiation was addressed within a range from power 20% to power 60% and the best results were achieved using ultrasonic power of 60%. At the same conducting conditions of temperature, Mu/Pz loading, and the incorporated methanol-to-oil ratio, the biodiesel yield attained 97.8% after 90 min by using ultrasonic irradiation as a mixing method at 60% power. The stability study of Mu/Pz catalyst revealed high reusability properties for five cycles using three regeneration solvents of distilled water, methanol and acetone with clear preferences for using the organic solvents. The specifications of the obtained biodiesel samples by both methods match the biodiesel requirements of the STM-D-6571 as well as the EN-14214 international standards.