Removal of a cationic dye -Methylene Blue- from aqueous media by the use of animal bone meal as a new low cost adsorbent

The Animal Bone Meal (ABM) prepared from the animal bone has been used as a new low cost adsorbent for the removal of Methylene Blue (MB) dye from aqueous solutions. Kinetics and equilibrium adsorption experiments were conducted to evaluate the adsorption characteristics of a cationic dye onto ABM. Results showed that the ABM could remove the dye effectively from aqueous solutions. The adsorption rate was fast and about 75% of adsorbed MB and was removed in less than 15 min.The effects of various process parameters i.e., temperature, pH, initial MB concentration, stirring speed, ionic strength and contact time on the adsorption capacity of ABM were investigated. The kinetic models for MB adsorption onto the ABM were studied. Langmuir isotherm showed better results for the ABM. The rates of adsorption were found to conform to the pseudo-second-order kinetic with good correlation. The separation factor (RL) revealed the favorable nature of the isotherm of the (MB-ABM) system. An activation energy of 25.2, 56.2 and 18.9 kJ/mol corresponding to initial concentrations of 25, 50 and 100 mg/L respectively were determined suggesting that the adsorption involved as a chemical reaction mechanism. The thermodynamic parameters, DG°, DH° and DS° were determined.