Uniform particles with a large surface area formed by hydrolysis of Fe2(SO4)3 with urea

Synthesis of poorly crystalline iron(III) hydrous oxides and basic salts (ferrihydrite, schwertmannite, and jarosite) consisting of uniform spherical particles of characteristic shape with a diameter of ∼10 μm is described. The preparation procedure is based on homogeneous precipitation of aqueous solutions of Fe2(SO4)3 with urea in the temperature range 60–100°C. Thermal dehydration of iron(III) hydroxide leads to an amorphous ferric oxide with a high surface area (∼200 m2/g) that is stable up to about 500°C.