Heat exchange capacity and physical properties of graphene oxide/carboxylated ferric tetroxide nanofluids

Nanofluid plays an important role in heat transfer engineering as a heat transfer medium. Therefore, we developed graphene oxide (GO)/carboxylated ferric tetroxide (Fe₃O₄–COOH) nanofluid with high stability using a two-step method. The preparation, characterization, physical properties and heat transfer properties of nanoparticles and nanofluids were investigated. The results show that GO/Fe₃O₄–COOH(GF) nanofluids present high stability at low concentrations (0.01 mass%, 0.05 mass% and 0.10 mass%) with absolute values of Zeta potential value greater than 30 mV. By adjusting the pH, it was found that GF nanofluids presented the best stability at pH = 10. A study of the physical properties of the nanofluids revealed that the viscosity of the GF nanofluids did not increase excessively with the addition of Fe₃O₄–COOH nanoparticles relative to the GO nanofluids. The heat transfer platform tests revealed that compared with the same concentration of GO nanofluids, the GF nanofluids have significantly higher heat dissipation efficiency. The temperature drop of 0.05 mass% GF nanofluid is higher than that of deionized water at the same pump power. We believe that well-stabilized GO nanofluids incorporating Fe₃O₄–COOH will provide more meaningful value in heat exchange than GO nanofluids.