Role of ultrasonication duration and surfactant on characteristics of ZnO and CuO nanofluids

Ultrasonication duration during the preparation of nanofluids has an important role on its various characteristics. Recently, role of surfactant is also found to be particularly significant on the properties of nanofluids. The role of ultrasonication duration and surfactant is together studied in this article on ZnO and CuO nanofluid. After number of experiments with different surfactants, stable ZnO nanofluid is prepared using both EBT (eriochrome black T) and OA (olylamine) surfactant while CuO is prepared using OA alone as it can be easily stabilized. Ultrasonication time is increased from 2 h to 8 h and different properties are analyzed in detail. Zeta potential, UV-vis analysis, pH value, specific heat capacity, specific gravity, viscosity, and thermal conductivity are analyzed for the three nanofluids. Stability of ZnO + EBT nanofluid is found to be excellent than the ZnO + OA and CuO + OA nanofluid. pH value, specific heat capacity, and specific gravity remained unaltered with increase in ultrasonication time while the remaining properties changed considerably. (paper)