Production and characterization of hierarchical zeolite Y catalyst for biodiesel production using waste cooking oil as a feedstock

This study reports the production and characterization of hierarchical zeolite Y (HZY) catalyst from commercial zeolite Y (CZY) for biodiesel using waste cooking oil as feedstock. The hierarchical zeolite Y catalyst produce were characterized using X-Ray diffraction (XRD), scanning electron microscopy (SEM) and Brunnauer, Emmeitt and Teller(BET) analysis. From the BET results of hierarchical Y zeolite produced shows that mole concentration of simultaneous desilication and mild dealumination determine the hierarchical factor of the produced hierarchical Y zeolite. Furthermore, this process was optimized by varying both the mole concentration aqueous solutions of Sodium Hydrides (NaOH) and Ethylenediaminetetraacetic acid (H(4)EDTA). The two process variables NaOH and H(4)EDTA were found to be statistically significant for high surface area, pore volume and pore size whereby, the value obtained for surface area are 193.83, 216.03, 212.34 and 218.33 m(2)/g while the hierarchy factor was calculated to be 0.0571, 0.1540, 0.1781 and 0.1042 respectively. The highest value of hierarchy factor (0.1781) of hierarchical zeolite Y sample (HZY-3) occur at 0.3 M of NaOH and 0.3 M of H(4)EDTA with a pore volume of 0.3785 c m(3)/g and a pore size of 8.5512 nm, which represent the most suitable for optimum reactivity compared to others. The XRD of hierarchical zeolite Y shows a slight decrease in the peak intensity which is associated with partial extraction of Si and Al from the zeolite framework during alkaline-to-acid treatment. Some peaks were also formed which show that the level of crystallinity has increased while the SEM/EDX determined the crystallite size and the morphology. From the EDX, the hierarchical zeolite Y Si/Al ratio was calculated to be 15.0. HZY gave a biodiesel yield of 94.8% at 55 degrees C for 90 mins while CZY gave a yield of 62.00% at the same condition. A reusability test was also carried out and it was observed that at repeated 5th runs, biodiesel yield using the same HZY catalyst dropped to 83% which was still reasonable enough compared to the CZY catalyst which was observed to have dropped to 41%. This indicates that the hierarchy factor of the HZY catalyst produced decides the activity of solid catalysts in biodiesel production.