The brown precipitate was
then collected by filtration and rinsed three times with deionized
water and ethanol. The washed precipitate was dried at 70 °C overnight.
Finally, Fe2O3 was calcined in air at 500 °C and held at this temperature
for the desired period of time (1 h and 2 h) in a muffled furnace to obtain
red Fe2O3 nanoparticles.