Green Synthesis, Characterization and Test of MnO2 Nanoparticles as Catalyst in Biofuel Production from Grape Residue and Seeds Oil

Abstract

The MnO2 nanoparticles, when used as catalyst, determine an enhanced reaction rate of the transesterifications process thus being very attractive for biodiesel production. One of the current limitations of the biofuel production by using MnO2 nanoparticles as catalyst is given by the reaction conditions. This work intends to improve the transesterification reaction efficiency through the use of a microwave field. It can generate large quantities of energy that lead to a good molecular motion thus favoring the transesterification process without altering the molecular structure. The aim of the present research is to explore the possibility of carrying out the microwave-assisted transesterification of grapes residues and seeds oil through the use of MnO2 nanoparticles as catalysts, as well as yeast (Saccharomyces cerevisiae), to efficiently obtain biofuel end product. Both chemically and biochemically (using plant extracts) synthesized MnO2 nanoparticles were produced and characterized by different techniques like TEM, XRD, BET, XPS, VSM. The analysis of obtained biofuel was performed by GC–MS. The comparison of results revealed that the samples prepared using plant extracts have morphologic properties higher than chemically prepared sample. MnO2 nanoparticles obtained by the use of oregano extracts were further tested for microwave assisted transesterification studies. The surface area of the MnO2 nanoparticles biochemically synthesized was four times higher than the nanoparticles synthesized by chemical method. The MnO2-oregano nanoparticles presented the best catalytic activity for biodiesel production as compared to the yeast catalyst. The use of microwave field for transesterification further enhances the efficiency of the process.