Sorption/desorption differences among three ferrihydrites prepared by different synthesis methods

Ferrihydrites named Fh-1, Fh-2, and Fh-3 were prepared under different environmental conditions. The sorption/desorption of Pb(II) onto/from the three ferrihydrites was studied. The effects of the most relevant operating conditions (e.g., pH, concentration of metal ions and temperature, etc.) were investigated. Adsorption/desorption isotherms were employed to evaluate the degree of reversible adsorption of Pb(II) onto the three ferrihydrites. Fh-3 exhibited the largest adsorption capacity and highest irreversible degree for Pb(II). Moreover, Fh-3 can lock metal ions very well. This phenomenon indicated that the formative conditions of ferrihydrite were critical in predicting the toxicity, transport, and fate of trace metals in a subsurface environment.