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This study aims at describing the removal of methylene blue (MB) from aqueous solution using bone charcoal (BC) as an adsorbent material. The effects of dye concentration, pH, contact time and the adsorbent dose were investigated. The chemical composition and solid structure of BC were analyzed using X-ray diffraction (XRD) and scanning electronic microscopy (SEM). The surface area was measured via the Brunauer-Emmett-Teller (BET) isotherm. The experimental data were analyzed with Langmuir, Freundlich and Temkin isotherm models. The results show that the main component of BC is calcium hydroxylapatite (Ca 5 (PO 4 ) 3 OH). The BET Suface area of BC is approximately 100 m 2 /g. The experimental adsorption isotherm complies with Langmuir equation model (R 2 = 0.99) and the maximum amount of adsorption (q max ) was 5 mg/g. The elevation of BC dose led to a decrease in q max , however, increasing the pH led to the elevation of dye adsorption. The kinetic studies revealed that the adsorption of MB is rapid and complies with the pseudo second-order kinetic (R 2 [ 0.99). Apart from R 2 , four error functions have been used for the validation of data. Analysis of data with Dubinin-Radushkevich isotherm showed that the energy of MB adsorption process onto BC was 2.65 kJ/mol, which implies that the adsorption of MB with BC is a physical adsorption.

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A B S T R A C TThe activated carbon prepared from Phoenix dactylifera fruit stones was tested for the removal of methylene blue (MB) dye from aqueous solutions. Batch studies were carried out to evaluate the impacts of initial solution pH (2-12), chemically activated carbon (CAC) concentration (0.25-5 g/L), MB concentration (50-400 mg/L), and contact time (20-430 min) on the adsorption of MB onto CAC. Results showed that the adsorption of MB was favorable at neutral pH. The results demonstrated that the Langmuir isotherm model best represented the equilibrium data with a maximum MB adsorption capacity of 478.32 mg/g. Pseudo-second-order kinetic model was found to adequately describe the adsorption process. The calculated thermodynamic parameters showed that adsorption process was spontaneous endothermic and physisorption was possible under examined conditions. In the final part of the study, the efficacy of CAC was examined by analyzing the removal of dye from industrial wastewater.

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