Structure of hydrous ferric oxide aggregates

The small angle light scattering behavior of hydrous ferric oxide flocs is examined here and found to provide useful insights into the nature of the a ggregates formed despite the large size of these aggregates at later times. The flocs appear to exhibit fractal properties over a significant size ran ge though the aggregates appear to be easily disrupted through mixing effec ts resulting in breakup and/or restructuring to denser assemblages. Backgro und electrolyte concentrations also have some impact on flee structure but mixing effects and apparent destabilization by ferric ions limit the effect of added electrolytes on the stability and structure of ferric oxyhydroxid es. Similar estimates of fractal dimensions of these hydrous ferric oxide f locs are obtained both by static light scattering analysis and by a cluster mass scaling approach. The choice of density distribution cutoff function has some impact on derived size and structure parameters and further refine ment in this area is needed. (C) 2000 Academic Press.