Biodiesel as a non-aqueous medium for the synthesis of nanomaterials: relevance to metallic particulate suspensions in biofuels and their removal

Abstract

In relevance to materials chemistry, this study presents biodiesel as an important non-aqueous medium for the synthesis of nanomaterials by demonstrating the synthesis of most versatile gold (Au) and silver (Ag) nanoparticles (NPs) in biodiesel medium. We show single-step in situ synthesis of Au and Ag NPs using biodiesels prepared from soybean and olive oil. Both biodiesels proved to be excellent solvents, reducing agents, and stabilizing agents for Au and Ag NPs. Au and Ag NPs were characterized by transmission electron microscope and XRD analyses, and were within the range of ∼10–50 nm. Colloidal stabilization of NPs by the surface adsorption of biodiesel was evaluated by detailed FT-IR analysis and determined to be driven by the ester head group of biodiesel molecules. Biodiesel-stabilized NPs in aqueous phase were efficiently extracted in the organic phase without using any phase transfer agent, suggesting the applicability of biodiesel in entrapping metal particulates and removing them from the aqueous phase with relevance to environmental sustainability.