No abstract

No abstract

Sono-sulfated zirconia nanocatalyst supported on MCM-41 was prepared by an ultrasound-assisted impregnation/hydrothermal hybrid method. The effect of irradiation power was studied by changing power of the sonication (30, 60 and 90W) during the synthesis which led to different physiochemical properties of the nanocatalyst. XRD, FESEM, EDX, FTIR and BET analyses exhibited smaller particles with higher surface area and less population of particle aggregates at highly irradiated nanocatalysts. The nanocatalyst irradiated at 90W for 30min showed a very narrow particle size distribution. About 59% of nanocatalyst particles were in the range of 1-30nm. The performance of investigated nanocatalysts in biodiesel production from sunflower oil showed ultrasound-assisted synthesized nanocatalysts had higher conversion in comparison to non-sonicated catalyst. Biodiesel conversion in catalyst with 90W and 30min ultrasonic irradiation exceeded 96.9% under constant condition at 60°C reaction temperature, methanol/oil molar ratio of 9:1 and 5% catalyst concentration. After five cycles, biodiesel conversion of non-sonicated catalyst was well maintained in a high extend (71.4%) while biodiesel conversion of non-sonicated catalyst barely reached to 43.5%. Among sonicated nanocatalysts, with increasing power of irradiation, the nanocatalyst represented higher conversion and reusability.

No abstract

Summary In present work, the aim of producing biodiesel from waste cooking oil was pursued by doping the cerium element into the MCM‐41 framework as catalyst with various Si/Ce molar ratio (5, 10, 25, 50, and Ce = 0). The catalytic performance and stability improved by employing the ultrasound irradiation in active phase loading step of catalyst preparation. The physicochemical characteristics of synthesized samples were investigated using various techniques as follows: Brunauer‐Emmett‐Teller (BET), X‐ray powder diffraction (XRD), Fourier transfer infrared (FTIR), energy‐dispersive X‐ray spectroscopy (EDX), transmission electron microscopy (TEM), and field emission scanning electron microscope (FESEM). The XRD patterns along with the results of FTIR and BET analysis revealed the MCM‐41 framework destruction while increasing the Ce content. The FESEM images of the nanocatalysts illustrated a well distribution and uniform morphology for the Ca/CeM (Si/Ce = 25). The particle size and size distribution of the Ca/CeM (Si/Ce = 25) were subsequently determined by TEM and FESEM images. The activity of fabricated nanocatalysts was evaluated by measuring the free acid methyl ester (FAME) content of produced biodiesel. The tests were carried out at constant operational conditions: T = 60°C, catalyst loading = 5 wt%, methanol/oil molar ratio = 9, and 6‐hour reaction time. A superior activity was observed for Ca/CeM (Si/Ce = 25) among other nanocatalysts with 96.8% conversion of triglycerides to biodiesel. The mentioned sample was utilized in five reaction cycles, and at the end of the fifth cycle, the conversion reached to 91.5% which demonstrated its significant stability.