DEVELOPMENT OF HIERARCHICAL ZEOLITE Y CATALYST FOR BIODIESEL PRODUCTION USING WASTE COOKING OIL AS FEEDSTOCK

Abstract

ABSRACT

This study reports development of hierarchical zeolite Y (HZY) catalyst from commercial zeolite Y (CZY) for biodiesel production using waste cooking oil as feedstock. The hierarchical zeolite Y catalyst developed was characterized using X-Ray diffraction (XRD), scanning electron microscopy (SEM) and Brunnauer, Emmett and Teller (BET) analyses. The BET showed 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 of aqueous solutions of Sodium Hydrides (NaOH) and Ethylenediaminetetraacetic acid (H4EDTA). The two (2) process variables NaOH and H4EDTA were found to be statistically significant for high surface area, pore volume and pore size. The values obtained for surface area of samples HZY-1,HZY-2,HZY-3 and HZY-4 were 193.83, 216.03, 212.34 and 218.33 m2/g while the hierarchy factor were 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 H4EDTA with pore volume of 0.3785 c m3/g and pore size 8.5512 nm, which represent the most suitable for optimum reactivity compared to the other samples. The X-Ray diffraction (XRD) of hierarchical zeolite Y shows slight decrease in the peak intensity which is associated with partial extraction of Si and Al from zeolite framework during alkaline to acid treatment. Some peaks were also formed which showed that the level of crystallinity had increased. 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 biodiesel yield of 95 % at 55 °C for 90 min. while CZY gave yield of 62.00% at the same conditions. 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 CZY catalyst which was observed to have dropped to 41 %. This indicates that the hierarchy factor of the HZY catalysts produced influences the activity of the catalysts in biodiesel production.