Effects of Various Inorganic Anions on the Formation of Fe_2O_3

The structures of Fe2O3 crystals,synthesized by precipitation method using ferric salts of nitrate,chloride and sulfate,were characterized using X-ray diffraction(XRD) technique,and its specific surface areas(SABET) were determined by N2 adsorption/desorption experiments.The speciation diagrams of ferric salts in aqueous solution were established by performing theoretical calculation using MEDUSA software and the functions of NO-3,Cl-and SO2-4 were evaluated by comparing SABET values of Fe2O3 particles before and after rinsing.The results indicate that the SABET of Fe2O3 prepared from ferric nitrate without rinsing is the largest and changes little after rinsing,while those from ferric chloride and sulfate show substantial increase.