ISSN print edition: 0366-6352
ISSN electronic edition: 1336-9075
Registr. No.: MK SR 9/7
Reaction of lead ions with hydroxylapatite granules
Madjid Hadioui, Patrick Sharrock, Mohamed-Oimar Mecherri, Véronique Brumas, and Marina Fiallo
LERISM, Paul Sabatier University, 31062 Toulouse, France
Received: 23 November 2007 Revised: 21 March 2008 Accepted: 21 March 2008
Abstract: In the effort to improve the performance of hydroxylapatite (HA) in removing lead ions from aqueous solutions, millimeter-sized
granules with 50 % porosity were synthesized. Such HA particles, after drying at 100°C, or heating at 800°C or 1100°C, exhibited
the specific surface areas of 50 m2 g−1, 25 m2 g−1, and 5 m2 g−1, respectively. It was found that heavy metal sorption capacity of HAs can be related to their surface area. Non-calcined
granules were difficult to handle and easy to crush. Hardened granules showed heavy metal absorption on their outer surfaces.
Absorption capacity of sintered HA particles towards lead was lower but adsorbed lead ions were spread inside the porous structure
of HA granules more evenly. Under flow conditions, lead ions were captured by HA at a rate of 0.5 mg g−1 min−1. Small lead phosphate aggregates were released from the HA sorbent together with calcium ions. Size of the aggregates depended
on the lead concentration and ranged from 1–50 μm in diameter; the aggregates could be removed by ultrafiltration. Results
show that porous hardened HA granules can be used as an efficient phosphate source for the immobilization of lead ions from
aqueous media. Organic ligands tend to interfere with the water purification procedure.
Keywords: hydroxylapatite - lead ions - water purification
Full paper is available at www.springerlink.com.
Chemical Papers 62 (5) 516–521 (2008)