Novel Synthesis of β‐FeOOH Nanofluid and Determination of Its Heat Capacity by an Adiabatic Calorimeter

Abstract

A novel and facile method for preparation of stable nanofluid is introduced, in which FeCl 3 •6H 2 O and urea were used as reactants without any surfactants. The obtained solid sample was proved to be β-FeOOH by XRD technology and spindle-shaped by TEM technology. The coexisting NH 3 molecules may be the main reason for the stable nanofluid. The weak bonding between nitrogen and iron atoms would be formed. The investigation on the excess heat capacity of the obtained nanofluid sustains this opinion. The heat capacities of the obtained β-FeOOH particles and the nanofluid were determined by an adiabatic calorimeter. And these obtained results will help the applications of β-FeOOH and the nanofluid to industry, and the establishment of the model of thermal conductivity of nanofluid. The thermodynamic properties of the obtained β-FeOOH particles and the nanofluid were calculated based on the obtained functions of heat capacity with respective to thermodynamic temperature and the relationships between the thermodynamic properties.