Studies on effect of various surfactants on stable dispersion of graphene nano particles in simarouba biodiesel

Abstract

Discovery of graphene has inspired researchers a range of potential applications. Conventional fluids with nanoparticle of size 1-100nm dispersed in them are called Nanofluids. Nanofluids are found to possess increased physical and thermal properties like thermal diffusivity, viscosity, thermal conductivity and convective heat transfer coefficient. These properties can be explored in the field of IC engines as additives in improving the engine performance and reducing the harmful emissions like NOx, CO, UBHC etc. In this work, a comparative study of two anionic dispersants Sodium Dodecyl Sulfate (SDS) and Sodium Dodecyl Benzene Sulfonate (SDBS) as dispersants for stable dispersion of graphene in Simarouba biodiesel with 20%blend in diesel (SME20) was made. Nanofluids samples of graphene at 20ppm and different mass fraction of SDBS & SDS were prepared. Dispersion of graphene was achieved by ultrasonication and magnetic stirring. Dispersion was characterized with Ultra Violet Visible (UV-Vis) spectroscopy. The UV-Vis absorption spectra revealed the presence of Graphene with characteristic λmax at around 250 nm. Experimental result showed that with increase in concentration of dispersant, the value of absorbance also increased. There is a linear relation between stability of dispersion and UV absorbency. An optimum graphene- to-surfactant ratio was determined. Surfactant concentration above or below this ratio was shown to decreases the stability of dispersion. For a mass fraction of 1:4, Graphene to SBDS ratio, the absolute value of UV absorbency was highest. Dispersion stability of SDBS was better than SDS at all concentration levels.