Nonaqueous synthesis of SrO nanopowder and SrO/SiO₂ composite and their application for biodiesel production via microwave irradiation

SrO/SiO₂ composite was synthesized in a few minutes by reacting Strontium acetylacetonate in benzyl alcohol with mm size SiO₂ beads using microwave radiation under argon atmosphere. The current work illustrates the optimization of a one-stage method whereby Nannochloropsis microalgae is converted to biodiesel using direct transesterification by microwave irradiation, the SrO/SiO₂ serving as a base catalyst. Microwave radiation accelerates the disruption of the microalgae cells, and eases the release of oil. The SrO/SiO₂ has been characterized by thermogravimetric analysis (TGA), powder X-ray diffraction (PXRD), scanning electron micrograph (SEM) and dynamic light scattering (DLS). The activity of the catalyst particles in the transesterification reaction was studied using ¹H NMR spectroscopy. The catalyst was reused for six cycles without appreciable loss in catalytic activity and the biodiesel yield of the Nannochloropsis microalgae was measured.