Billah, Rachid El KaimSimsek, SelcukKaya, SavasKatin, KonstantinEssenni, SaidJugade, RavinShekhawat, Anita2025-05-042025-05-0420250022-28601872-8014https://doi.org/10.1016/j.molstruc.2024.140712https://hdl.handle.net/20.500.12418/35488The presented work aims to investigate the cadmium adsorption on nano-crystalline hydroxyapatite (n-Hap). X ray diffraction (XRD), Fourier transform infra-red (FTIR), Scanning electron microscope (SEM), and Thermogravimetric analysis (TGA) techniques were applied to characterize the n-Hap. Adsorbent mass, pH value, and initial Cd2+concentration were varied to optimize the adsorption conditions. The best Langmuir adsorption isotherm provided equilibrium adsorption capacity of 52.79 mg/g. According to performed kinetic study, the surface reaction fits to the pseudo-second order model. Thermodynamic parameters of the adsorption (Delta G degrees, Delta H degrees and Delta S degrees ) were derived from the temperature dependence of the adsorption rates. We observed spontaneous endothermic chemisorption of Cd2+ ions. Density functional theory calculations confirmed the spontaneous chemisorption via formation of three Cd-O covalent bonds of about 2.1 & Aring; lengths.en10.1016/j.molstruc.2024.140712info:eu-repo/semantics/closedAccessKineticsThermodynamicCd2+removalHydroxyapatiteDFTArticle13252-s2.0-85211017020Q1WOS:001409284800001Q2