Immobilization of lead by apatite
- Ohio State Univ., Columbus, OH (United States)
Previous studies have shown that lead interactions with hydroxylapatite induced hydroxypyromorphite precipitation and thus can reduce Ph solubility. In the present study we investigated the solid-phase speciation of lead, immobilized by synthetic hydroxylapatite and natural fluoro- and chlorapatites. In order to understand the mechanisms of lead immobilization (precipitation of pyromorphite, etc), we studied the phosphates formed after reaction of aqueous lead with apatites or after co-precipitation of (Ph, Ca)-phosphates. These phosphates were analysed by different spectroscopic methods (XRD, IR, EXAFS and SEM) to determine the structure of the precipitated Pb-phosphates, and the mechanisms of formation of pyromorphite (OH{sup -}, F{sup -} and Cl{sup -}) as a function of pH, solid/solution ratio, and the reacting mineral and solution chemistry. The preliminary results showed that pure pyromorphite and not (Pb, Ca)-apatite was formed when we let aqueous lead react with apatite. (Pb, Ca)-apatite can be formed only by co-precipitation.
- OSTI ID:
- 370485
- Report Number(s):
- CONF-960376--
- Country of Publication:
- United States
- Language:
- English
Similar Records
Formation of pyromorphite in anglesite-hydroxyapatite suspensions
In situ immobilization of lead from aqueous solutions and contaminated soils by phosphate rocks