Study on Rheological and Stability of Natural Derived Carbon Nanosphere Nanofluids

In this work, carbon nanosphere derived from a waste rice husk (RH) were prepared through chemical treatment and calcination process. Moreover, the carbon nanofluids (CNF) were developed using simple chemical treatment assisted by ultrasound technique. Different composition of carbon nanosphere (CNS) were taken into experiment to determine the optimum and best properties. Ultrasound techniques were introduced in this study to reduce the agglomeration of the particle. Surface morphology of CNS were analysed by Scanning Electron Microscopy (SEM). The sphere shape from the particle/grain were identified from the nanoparticle and proves the terms of “nanosphere”. Viscosity of the nanofluids were studied by rheological testing (Antoon PAR, MAR 3). Flow curve of nanofluids showed that at minimum inclusion of CNS improved the stress of the fluid significantly. More to the addition, dynamic viscosity measure possesses that addition of CNS stabilized the properties of the fluid compared to virgin base fluid. The stability of the CNF was investigated through UV-Vis. Findings shows that, the stability of the nanofluids stabilized starting from 1 week onwards as evidenced by UV-Visible spectrophotometer analysis. Furthermore, little to no precipitate noticed even after 8 weeks. This work offers greener approach for nanofluids which organic derived and environmentally friendly (very low percentage of nanoparticle, 0.02 vol% (equivalent to 0.002 wt %).