EFFECTS OF PARTICLE AGGREGATION MECHANISMS ON METAL UPTAKE TO NANOSCALE GOETHITE

摘要

It is well known that iron oxides have a high potential to remove metals from aqueous environments. Geochemical environmental factors such as pH, ionic strength and drying and freezing processes can alter the extent of particle aggregation of iron oxides. Consequently, the degree of particle aggregation can greatly affect the mode of metal uptake onto iron oxide surfaces, e.g., from strictly adsorbed species to more strongly associated forms including co-precipitates and structurally incorporated phases. In the present study, metal uptake onto and desorption from goethite nanoparticles aggregated under various geochemical conditions is studied through batch experimentation to determine how the mechanism of aggregation influences the extent, potential mode and long-term permanence of metal sequestration. Results have implications for determining remediative strategies that aid the transformation of metal contaminants from the aqueous phase to immobile solid forms.