Removal of lead and cadmium from aqueous solution using octacalcium phosphate as an adsorbent

Abstract

Octacalcium phosphate (OCP) is a material from the calcium phosphate group with a crystal structure similar to hydroxyapatite. The removal process of lead and cadmium in aqueous solution using octacalcium phosphate material was investigated. OCP material was synthesized by the solution precipitation method. The structural and phase properties of OCP before and after the removal process were determined by the X-ray diffraction (XRD) method. Microstructural and semi-quantitative analysis of the material was investigated by scanning electron microscopy and energy dispersive X-ray spectroscopy (SEM-EDS). Characteristic bands and functional group determination were revealed using the Fourier-transform infrared spectroscopy with attenuated total reflection (FTIR-ATR). As target pollutants, Cd(II) and Pb(II) were chosen in adsorption experiments. Results show that OCP in the first 10 min has a very fast removal rate for Pb(II); the equilibrium state was reached after 10 min with more than 98 % adsorption efficiency. Results for Cd(II), results showed the same removal rate but somewhat lower adsorption efficiency, amounted to approximately 63 %.

Keywords

• calcium phosphate material
• adsorption
• water purification
• heavy metals