REMOVAL OF LEAD IONS FROM AQUEOUS SOLUTION USING BENTONITE AND NANOCOMPOSITE BENTONITE /CALCIUM DEFICENT HYDROXYAPATITE

Abstract

In this study, nanocomposite (B/CDHAp) from Bentonite (B) and Calcium-deficient Hydroxyapatite (CDHAp) were synthesized by co-precipitation method and investigated for lead ions adsorption. The Energy Dispersive X-ray (SEM-EDX) analysis showed Calcium: Phosphorus (Ca:P) molar ratio = 1,53. The structure and properties of B/CDHAp, HAp, Bentonite were characterized by Fourier-transformed Infrared Spectroscopy (FTIR), X-ray diffraction (XRD) and Transmission electron microscopy (TEM) methods. The FTIR spectra of nanocomposite (B/CDHAp) showed typical Hydroxyapatite peaks correspond to phosphate (PO₄^3-), carbonate (CO₃^2-), hydroxyl groups (OH^-) and chemical bonds Si-O, Al-O that characterized Bentonite. XRD and TEM observations have shown that the nanoparticles (B/CDHAp) are of about 10- 50 nm in size. The adsorption of Pb (II) onto Bentonite and B/CDHAp fitted well to the Langmuir isotherm model, with a maximum capacity of 55,71 mg.g^-1 and 76,92 mg.g^-1, respectively. The results show that B/CDHAp is more efficient adsorbent for Lead ions in compare with Bentonite.