Synthesis, characterization, physicochemical, and electrical properties of natural (bio) nanofluids

Energy conservation and sustainability to reduce the dependence on conventional sources have resulted in modified or advanced process practices. One such is the use of nanofluids for enhanced energy efficiency. However, such practices must not be at the cost of environmental hazards. The current study emphasizes bio-based nanofluids formulated at five different volumetric concentrations (0.2%, 0.4%, 0.6%, 0.8%, and 1.0%) using Flamboyant (Royal Poinciana) tree bark nanoparticles with ethylene glycol as base fluid. The nanoparticles synthesized by cost-effective extensive ball milling technique were spherical in shape. Analyzing the nanofluid with TEM confirms the particles as evenly distributed with an average diameter of 26 nm. Elemental analysis shows that the bio powder contains oxides of Calcium and Silicon. The pH, electrical conductivity, and viscosity of the prepared flamboyant tree bark-ethylene glycol (FTB-EG) nanofluid were quantified between 20 and 70°C. Although the properties enhanced with increase in concentration, the viscosity and pH decreased with temperature rise, while the electrical conductivity behaved contradictory. The maximum and minimum values of the properties were attributed to 1.0% and 0.2% concentrations, respectively. The correlations were proposed and the deviation between the measured and correlation data was less than 10%.