Method of preparing iron oxide nanoparticles

A method of preparing oval shaped iron (III) oxide nanoparticles, the method comprising:

• preparing a ferric chloride (FeCl3) aqueous solution;
• preparing a sodium hydroxide (NaOH) aqueous solution;
• obtaining a mixed aqueous solution consisting of the ferric chloride (FeCl3) aqueous solution, the sodium hydroxide (NaOH) aqueous solution, and a sodium sulfate (Na2SO4) aqueous solution;
• reacting the mixed aqueous solution in an electric convection oven in a temperature range of 100° C. to 105° C. for 90 hours to 100 hours at atmospheric pressure to get a solid product;
• and
• cooling, washing, and drying the solid product to get a dried product,
• wherein a concentration of the FeCl3 aqueous solution is in a range of 2 M to 3 M,
• a concentration of the NaOH aqueous solution is in a range of 5 M to 6 M,
• a concentration of the Na2SO4 aqueous solution is in a range of 0.5 M to 1 M, and
• the dried product consists of iron (III) oxide.