Adsorption of cobalt(II) from aqueous solution onto hydroxyapatite/zeolite composite

The Hydroxyapatite/Zeolite (HApZ) composite were synthesized by precipitation method and used as an adsorbent for the removal of cobalt ions from the aqueous solution. The materials were characterized by scanning electron microscope (SEM) and Fourier transform infrared (FTIR) spectroscopy. It has been observed that there was slight enhancement in the % removal of cobalt ions from aqueous solution by HApZ (63%) than HAp (58%) and zeolite (47%). Batch experiments were performed to observe the effect of pH, adsorbent dose, contact time and initial cobalt (II) concentration. Kinetic study shows that the adsorption process follow pseudo-second order kinetic model. Equilibrium data were well fitted to Langmuir and Freundlich isotherm model.