Irreversible Trace Metal Binding to Goethite Controlled by the Ion Size.

The dynamics of trace metals at mineral surfaces influence their fate and bioaccessibility in the environment. Trace metals on iron (oxyhydr)oxide surfaces display adsorption-desorption hysteresis, suggesting entrapment after aging. However, desorption experiments may perturb the coordination environment of adsorbed metals, the distribution of labile Fe(III), and mineral aggregation properties, influencing the interpretation of labile metal fractions.

Exchange of Adsorbed Pb(II) at the Rutile Surface: Rates and Mechanisms.

The dynamics of Pb(II) at mineral surfaces affect its mobility in the environment. Pb(II) forms inner- and outer-sphere complexes on mineral surfaces, and this adsorbed pool often represents a large portion of the bioaccessible Pb in contaminated soils. To assess the lability of this potentially reactive adsorbed Pb(II) pool at metal oxide surfaces, we performed Pb(II) isotope exchange measurements between dissolved Pb(II) enriched in Pb and natural isotopic abundance Pb(II) adsorbed to rutile at pH 5, 6, and 7.

Effects of Cu(II) and Zn(II) on PbO Reductive Dissolution under Drinking Water Conditions: Short-term Inhibition and Long-term Enhancement.

Lead oxide (PbO) has the lowest solubility with free chlorine among Pb corrosion products, but depletion of free chlorine or a switch from free chlorine to monochloramine can cause its reductive dissolution. We previously reported that Cu(II) and Zn(II) inhibited PbO reductive dissolution within 12 h. Here, we expanded on this work by performing longer duration experiments and further exploring the underlying mechanisms.