Preparation of iron oxides

[0017]A sample of high surface area ferrihydrite is prepared by the inventive process presented herein as follows: A stainless steel gas sparger is fitted into the bottom of a 1 liter jacketed vessel and the temperature is adjusted to hold at about 30° C. About 400 mL of deionized water is added to the vessel and agitation is started at a mix rate of about 1000 RPM. About 53.3 g of an iron powder blend (80 / 20 blend of Ancorsteel 1000 and ATW-432, both commercially available from Hoeganaes, and each having an iron metal surface area of about 0.2 m2 / g) is added to the water with mixing. The iron powder is added slowly enough to maintain a reaction temperature of less than about 30° C. A nitrogen purge is started at a rate of about 35 liters per hour. About 115.2 g of glacial acetic acid (commercially available from Fisher Chemicals) is added to the iron and water mixture with a continuing nitrogen purge. The jacketed vessel temperature is maintained at about 30° C. and the nitrogen p

[0018]A sample of high surface area iron oxide with low crystallinity is prepared by the inventive process presented herein as follows: A stainless steel gas sparger is fitted into the bottom of a 1 liter jacketed vessel and the temperature is adjusted to hold at about 30° C. About 500 mL of deionized water is added to the vessel and agitation is started at a mix rate of about 1000 RPM. About 66.6 g of an iron powder blend (80 / 20 blend of Ancorsteel 1000 and ATW-432, both commercially available from Hoeganaes, and each having an iron metal surface area of about 0.2 m2 / g) is added to the water with mixing. The iron powder is added slowly enough to maintain a reaction temperature of less than about 30° C. A nitrogen purge is started at a rate of about 35 liters per hour. About 36.0 g of glacial acetic acid (commercially available from Fisher Chemicals) is added to the iron and water mixture with a continuing nitrogen purge. The jacketed vessel temperature is maintained at about 30° C