Preparation, characterization and evaluation of x-MoO3/Al-SBA-15 catalysts for biodiesel production

Joyce S B Figueiredo,José J N Alves,Bianca V S Barbosa,Bruno T S Alves,Vitória A Freire

doi:10.1007/s40243-021-00204-x

Abstract

Biodiesel is an alternative source of renewable energy that can be produced by a transesterification of vegetable oils. Mesoporous molecular sieves, such as SBA-15, due to high surface area and thermal stability are promising precursors for heterogeneous catalysts in the transesterification reaction. In this work, Al-SBA-15 precursor was obtained by direct hydrothermal synthesis, impregnated with different MoO3 contents (5, 10 and 15 wt%) by the pore saturation method, and evaluated as heterogeneous catalyst in the production of biodiesel from a transesterification of soybean oil with methanol. Al-SBA-15 precursor as well as MoO3/Al-SBA-15 catalyst were characterized for its structural characteristic by X-ray diffraction, textural characteristic by N2 adsorption analysis, and thermal stability by thermogravimetric analysis. An experimental planning 22 + 3 CtPt was used to evaluate the influence of MoO3 content and reaction time on biodiesel yield from soybean oil and methanol. The biodiesel content in the final product was obtained by gas chromatography. An average biodiesel yield of 96% was obtained with the catalyst 10%MoO3/Al-SBA-15 under the following reaction conditions: 20:1 methanol/soybean oil molar ratio, and 3 wt% of catalyst loading at 150 °C in 3 h. After five consecutive reaction cycles, the biodiesel yield decreased by about 34%. The density and acidity of the biodiesel produced are within the specified values for commercialization according to international standards.Graphical abstract

Highlights

Fossil fuels are the main energy source in the global energy system
Biodiesel is a mixture of mono alkyl esters produced in a transesterification reaction, in which triglycerides from different sources of vegetable oils or animal fats react with a short chain alcohol, usually methanol or ethanol in the presence of a homogeneous, heterogeneous or even enzymatic catalyst [7]
This study focused on catalyst preparation and evaluation for biodiesel production, taking as input variables the catalyst composition and reaction time, and biodiesel yield as response variable

Summary

Introduction

Fossil fuels are the main energy source in the global energy system. the increase in global energy demand, uncertainties regarding the availability of oil in the future, and the environmental impacts caused by burning fossil fuels, are factors that justify the need to search for alternative sources of renewable energy to avoid an energy crisis [1,2,3]. The optimum M oO3 content was 25 wt% incorporated in the B-ZSM-5 nanocatalyst, and the optimal operating conditions were reaction time of 6 h, temperature of 160 °C, catalyst concentration of 3 wt%, and methanol/oleic acid molar ratio of 20:1. The effect of methanol to oil molar ratio, catalyst dosage, microwave power and reaction time on yield of biodiesel was evaluated using an experimental planning.

Results

Conclusion