Copper-doped Hydroxyapatite for Removal of Arsenic(V) from Aqueous System

Abstract

In this work, pure and copper-doped hydroxyapatite (various wt% of Cu) were synthesized by wet chemical precipitation method using eggshells as source of calcium. The efficiency of the prepared materials for removal of arsenic(V) from aqueous system has been investigated. Pure and Cu(II)-doped HAP were calcined at different temperatures ranging from 100-600 °C. The synthesized HAPs were characterized by Fourier Transform Infrared (FT-IR) spectroscopy, X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Energy Dispersive X-ray Spectroscpic Analysis (EDS), particle size analysis based on dynamic light scattering measurements, and BrunauerEmmettTeller (BET) surface area analysis. FT-IR spectra and XRD patterns of synthesized HAPs confirmed the formation of single HAP phase. XRD patterns showed decrease in crystallite size for Cu-HAP compared to pristine HAP. BET surface area of Cu-HAP calcined at 300 °C increased to 153.39 m²g^-1 from 66.80 m²g^-1 for pure HAP. Finally, the synthesized HAPs were applied to remove As(V) from aqueous system. As(V) removal efficiency for Cu-HAP was two-fold higher than that of pure HAP. Adsorption behaviors were analyzed for As(V) adsorption on thermally treated pure and Cu-HAP using Langmuir, Freundlich, and Temkin adsorption isotherms. Finally, the prospect of Cu(II)-doped HAP for treatment of waste water containing heavy metals has been discussed.