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 homogeneous precipitation from Fe(NO3)(3) solution in the presence of SO4-2 ions and characterized by various techniques. Although the cell parameters, cell volumes, and crystallite sizes of all the samples prepared under different conditions remain almost same, the surface area, micropore-mesopore ratio, pore volume, pore radius, particle size, and surface acidity are influenced by SO4-2/Fe+3 ratio, initial pH, and temperature 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 predominantly micropores and possesses high surface area (133.5 m(2)/g) and acid sites (100 mu mol/g). (C) 1996 Academic Press, Inc.