MoO3 Catalyst Supported on Micro-Mesoporous Structure for Biodiesel Production

Abstract

This study reports the synthesis and characterization of x_MoO₃/H-Z/S micro-mesoporous catalyst, which combines the properties of ZSM-5 and SBA-15, as well as its performance for biodiesel production from the transesterification of soybean oil. ZSM-5 was added to the SBA-15 synthesis gel, calcinated, and molybdenum trioxide (MoO₃) was incorporated by incipient wetness using ammonium heptamolybdate salt [(NH₄)₆Mo₇O₂₄‧4H₂O] as a metal precursor. The diffractograms and micrographics showed a micro-mesoporous structure of the support with the characteristic peaks of MoO₃. The textural analysis showed that increasing the MoO₃ content decreases the specific area and the pore diameter of the catalysts. The Raman spectrum of the catalysts indicated vibration modes characteristic of the active species MoO₃ in the orthorhombic phase. The methanol/oil molar ratio was the variable that most influenced the yield of methyl esters within the levels of a design of experiments matrix. The highest biodiesel yield of 79.2% was obtained with 6 (wt.%) of MoO₃, 4 h of reaction time, and a methanol/oil molar ratio of 20/1. This reaction condition uses a lower molybdenum content, lower catalyst load, and lower methanol/oil molar ratio than those reported in the literature, which qualitatively reduces the process costs. A quantitative economic analysis must be further performed to define the economic viability of the process.

Graphical Abstract