Textural evolution of hierarchical nanostructured ZSM-5 via sono-hydrothermal design by various carbon shapes for efficient biodiesel production

Bifunctional acid/base nanocatalysts were fabricated with several secondary hard-templated ZSM-5 supports to produce biodiesel. Carbon active, charcoal, graphite and multi-wall carbon nanotube were carbonaceous sources used as template. Furthermore, ultrasound was utilized to increase dispersion of the carbon particles. The nanocatalysts were characterized by XRD, FESEM, TEM, EDX, BET-BJH, TPD-CO2, TPD-NH3 and TPR techniques and then investigated in the transesterification of sunflower seed oil. Results proved the improvement of catalytic properties and performance by adding all carbon templates except the graphite. The sonicated and charcoal templated sample had the highest mesopore volume resulting in 90.4 % conversion of oil. TEM images showed the meso pores created by carbon template and proved the enhanced pore distribution resulted by sonication. TPD-CO2 confirmed the enrichment of strong catalytic sites by addition of carbon templates as well as sonication. The sonicated nanocatalyst showed higher stability with only 2.4 % conversion drop after five cycles.