Characterization of Hydroxyapatite Synthesized from Calcium Hydroxide and Phosphoric Acid as Adsorbents of Lead in Wastewater

Abstract

Calcium hydroxyapatite (also known as hydroxyapatite - HA), formula Ca5(PO4)3(OH) or Ca10(PO4)6(OH)2, is a double salt of tri - calcium phosphate and calcium hydroxide. And apatite exists naturally in the form of fluorine-apatite Ca10(PO4)6F2. In human and animal body, HA is the main component in bone (accounting for 65-70% weight) and teeth (99%). In this study, calcium hydroxide (Ca(OH)2) and phosphoric acid (H3PO4) were used as raw materials to produce hydroxyapatite (HA). The hydroxyapatite was synthesized by hydrothermal method. Physico-chemical and microstructural properties of the HA were characterized by X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), Brunnaeur-Emmett- Teller (BET) analysis and Scanning Electron Microscope (SEM) and compared with standard sample of HA. For lead treatment in wastewater, adsorption of HA was tested by measuring concentration of lead of the adsorption process. In which, Pb is one of the toxicity heavy metals that caused many dangerous diseases and threatening human health and life.