Porous hydroxyapatite (HAp) monoliths synthesized from gypsum mold waste were used for removing lead ions from aqueous solution. The gypsum waste was crushed into small blocks and converted directly to porous HAp pieces in a 0.5 mol/dm3 diammonium hydrogen phosphate solution at 55 and 80°C. Porous structures were effected by reaction temperatures. Twenty and 40 mg of lead ions were removed from 100 cm3 aqueous solution by stirring with 1.0 g porous HAp monoliths at pH 3 for 5 to 30 min. HAp was dissolved in the pH 3 acidic solution, but Pb-Cl apatite, which was formed from Pb2+, PO43- and Cl-, was stable in the pH 3 acidic solution.
All Science Journal Classification (ASJC) codes
- Ceramics and Composites
- Condensed Matter Physics
- Materials Chemistry