The fate of Pb in the environment is hi
ghly dependent onsorption and desorption reactions on solid surfaces. Inthis study Pb sorption and desorption kinetics on
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ges/
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2O
3at pH 6.50,
I = 0.1 M, and [Pb]
initial = 2 mM were investi
gatedusin
g both macroscopic and spectroscopic measurements.X-ray absorption fine structure (XAFS) spectroscopyrevealed a Pb-Al bond distance of 3.40 &Arin
g;, consistentwith an inner-sphere bidentate bondin
g mechanism. XAFSresults show no chan
ge with time in the avera
ge localatomic structure surroundin
g the Pb and no indication ofthe formation of Pb surface precipitates. Adsorption kineticswere initially fast, resultin
g in 76% of the total sorptionoccurrin
g within 15 min, followed by a slow continuoussorption reaction likely resultin
g from diffusion throu
ghmicropores. Desorption at
I = 0.1 M and pH 6.50 was studiedusin
g a cation-exchan
ge resin as a sink for Pb(aq).Under these conditions, Pb desorption was 98% reversiblewithin 3 days of incubation time. Furthermore, desorptionand adsorption kinetics demonstrated similar trends: afast reaction followed by a slow reaction. The useof spectroscopy combined with adsorption and desorptionkinetic studies has revealed important information onthe interaction between lead and aluminum (hydr)oxides.This information is valuable for predictin
g the fate of Pb inthe environment.