Comparative study on the removal of zinc(II) by bovine bone, billy goat bone and synthetic hydroxyapatite

The objective of this work is to investigate the possibility of using a low cost and naturally available apatite rich adsorbents from animal bones such as bovine bone (BV) and billy goat (BG) bones for the removal of zinc(II) from aqueous solutions. The adsorption studies were compared with synthetic hydroxyapatite (HAPs). The samples were characterized by thermogravimetry (TG), Fourier transform infrared spectroscopy (IR) and X-ray diffraction (XRD). The equilibrium isotherm data were fitted to the Langmuir, Freundlich, Temkin, Elovich and Dubinin-Redushkevich isotherm equations to obtain the characteristic parameters of each model. The adsorption of Zn(II) on BV and BG fitted well with the Langmuir isotherm where as HAPs fitted well with Dubinin Raduskevich isotherm model. The kinetic studies showed that the sorption rates could be described well by a pseudo-second-order kinetic model. Also it was shown that the adsorption of Zn(II) could be fitted to the intraparticle mass-transfer model. The studies showed that BG, BV and HAPs can be used as an efficient adsorbent material for the treatment of Zn(II) from water and wastewater. The order of the removal capacity for these adsorbents was determined as HAPs (93%) > BG (90%) > BV (82%).