In this study, nanoporous hydroxyapatite was synthesized and functionalized via tetraethylenepentamine in order to obtain a novel adsorbent for efficient removal of Acid Blue 25 dye from aqueous solution. Functionalized hydroxyapatite was characterized by Fourier transform infrared spectroscopy (FTIR), X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Energy Dispersive Spectroscopy (...