Formation of Chloropyromorphite from Galena (PbS) in the Presence of Hydroxyapatite

Abstract

Transformation of unstable lead [Pb(ll) under various pH Condition to determine the formation rate of pyromorphite and the solubility of galena under the ambient conditions. In a 6 day reaction period the dissolution rate of galena increased with pH due to the oxidation of dissolved sulfide.Correspondingly, formation of chloropyrornorphite became apparent in the galenaapatite suspensions with increasing pH. The insignificant effect of mineral P/Pb molar ratio on the formation of chloropyromorphite implied that dissolution of galena was the 1 rate limiting step.

Selenium Improves Physiological Parameters and Alleviates Oxidative Stress in Shoots of Lead-Exposed Vicia faba L. minor Plants Grown Under Phosphorus-Deficient Conditions

“…Then, the seedlings were transplanted into 3 L plastic containers (ten plants per one container) with modified full-strength Hoagland's medium (Hoagland and Arnon 1959) containing the following mineral components (POCH): KNO 3 (6 mM), Ca(NO 3 ) 2 9 4H 2 O (4 mM), MgSO 4 9 7H 2 O (2 mM), iron citrate (0.85 lM), H 3 BO 3 (46 lM), MnCl 2 9 4H 2 O (9 lM), ZnSO 4 9 7H 2 O (0.76 lM), CuSO 4 9 5H 2 O (0.32 lM), and H 2 MoO 4 9 2H 2 O (0.11 lM). To prevent precipitation of lead phosphate in growth solution (Zhang and Ryan 1999), NH 4 H 2 PO 4 was removed from the Hoagland's solution in all experimental groups (Wierzbicka and Potocka 2002). Next, the experiment was conducted in P deficiency conditions for 14 days.…”

“…Addition of phosphate to a Pb-containing growth solution reduced the bioavailability of Pb (Zhang and Ryan 1999). Hence, to prevent precipitation of lead phosphate in the growth solution, we conducted the experiment in P-deficient conditions.…”

Peer Reviewed: Reducing Children's Risk from Lead in Soil

“…Further, environmentally relevant concentrations of other metals had no significant effect on lead immobilization by hydroxyapatite; in fact, hydroxyapatite may remove the metals (38). Also, pyromorphite formation from lead adsorbed on goethite (Fe(OH) 3 ) (39) and primary lead minerals, including cerrusite (PbCO 3 ) (40, 41), anglesite (PbSO 4 ) (42), litharge (PbO) (40), massicot (PbO) (40), and galena (PbS) (43), by addition of apatite have been reported. The completeness and kinetics of this transformation depend on the mineralogy of lead, the amount of apatite added, and the pH of the system.…”

Soil lead bioavailability and in situ remediation of lead‐contaminated soils: A review

“…Zhang and Ryan [55][56][57] studied the reactions between mixtures of synthetic HA and anglesite, cerrusite, or galena in suspensions of 0.001 M NaCl and 0.1 M NaNO 3 . Two separate experiments were conducted: [1] constant pH experiments at pH 2 to 7 and [2] variable pH experiments where pH started at 2 and increased to 7 within 30 min.…”