Sono-dispersed MgO over cerium-doped MCM-41 nanocatalyst for biodiesel production from acidic sunflower oil: Surface evolution by altering Si/Ce molar ratios

Abstract

In the present work, Mobil Composite Material no. 41 (MCM-41) utilized as the catalyst support for biodiesel production from Waste Cooking Oil (WCO). Different amounts of Si/Ce molar ratios (5, 10, 25, 50 and Ce = 0) introduced to the MCM-41 structure to synthesize the bifunctional nanocatalysts and achieve a modified support of high stability and acidity. Then, ultrasound used to disperse MgO active phase on support surface. The prepared nanocatalysts were investigated using various techniques as follows: XRD, EDX, TEM, FESEM, FTIR and BET. 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 Mg/CeM (Si/Ce = 10). The particle size and size distribution of the Mg/CeM (Si/Ce = 10) were subsequently determined by TEM and FESEM images. Biodiesel production carried out under following constant operational parameters to evaluate catalytic performance of synthesized samples: T = 70 °C, catalyst loading = 5 wt%, methanol/oil molar ratio = 9, and 6 h reaction time. Ce substitution in support framework considerably enhanced the biodiesel conversion. The Mg/CeM (Si/Ce = 10) nanocatalyst demonstrated the highest conversion of 94.3%. The reusability of the Mg/CeM (Si/Ce = 10) studied in seven reaction cycles and biodiesel conversion reached to 88.7% at the end of seventh cycle which demonstrated its significant stability.