STUDIES ON FERRIC-OXIDE HYDROXIDES .2. STRUCTURAL-PROPERTIES OF GOETHITE SAMPLES (ALPHA-FEOOH) PREPARED BY HOMOGENEOUS PRECIPITATION FROM FE(NO3)(3) SOLUTION IN THE PRESENCE OF SULFATE-IONS

A series of goethite samples (alpha-FeOOH) have been prepared by homog eneous precipitation from Fe(NO3)(3) solution in the presence of SO4-2 ions and characterized by various techniques. Although the cell param eters, cell volumes, and crystallite sizes of all the samples prepared under different conditions remain almost same, the surface area, micr opore-mesopore ratio, pore volume, pore radius, particle size, and sur face acidity are influenced by SO4-2/Fe+3 ratio, initial pH, and tempe rature of hydrolysis. The sample prepared at SO4-2/Fe+3 ratio of 0.5, initial pH of 1.5, and hydrolysis temperature of 90 degrees C has pred ominantly micropores and possesses high surface area (133.5 m(2)/g) an d acid sites (100 mu mol/g). (C) 1996 Academic Press, Inc.