ZnO Nanorod Based Nanofluids

This contribution presents the development of ZnO nanorods based nanofluids and their potential application of the thermal management in photo(bio) reactors. ZnO nanorods with a diameter of similar to 140 nm and spatial ratio of >5 were synthesized by the hydrothermal methods. The thermal conductivity of their water suspensions has been measured by changing the loading, additives, and pH of the nanofluids. At low concentrations, there was an enhancement of the effective thermal conductivity of the basic fluids by over 30%. ZnO nanorods/phosphate buffer (pH 7.02-7.04) suspensions showed very good stability. These suspensions were found to be suitable as basic fluids for the growth of cyanobacteria. With a suitable concentration of the dispersed cyanobacteria, over 13% enhancement in thermal conductivity was observed without significant change in electrical conductivity. Upon verification by further experiments, these ZnO nanofluids may have the potential application in thermal management of photo(bio) reactors.