Hierarchical Zeolites as Catalysts for Biodiesel Production from Waste Frying Oils to Overcome Mass Transfer Limitations

Hierarchical crystals with short diffusion path, conventional microcrystals and nanocrystals of ZSM-5 zeolites were used for biodiesel production from waste frying oils assessed their catalytic activity in regard to pore structure acidic properties. Produced characterized using XRD, nitrogen adsorption–desorption, SEM, TEM, X-ray fluorescence, FTIR. Pore size effect on molecular limitation was by Thiele modulus calculations turnover frequencies (TOF) discuss the correlation between character performance zeolites. Owing enhanced accessibility mass transfer triglycerides free fatty acids elemental active zeolitic structure, nanosponge nanosheet hierarchical highest. A maximum yield 48.29% reached transesterification (WFOs) HZSM-5 nanosheets at 12:1 methanol WFOs molar ratio, 180 °C, 10 wt % catalyst loading, 4 h reaction time. Although nanosponges achieved high conversions, these more hydrophilic did not function according entire strength comparison nanosheets. NSh-HZSM5 still after consecutive cycles as a result zeolite regeneration.