BIOSORPTION OF COPPER CU (II) INTO BIOMASS CACTUS RACKETS OF THE MOROCCAN REGION OF MEKNES: APPLICATION OF ISOTHERM AND KINETIC MODELS

The biosorption of copper Cu(II) ions using the  biomasses (opuntia ficus-indica)  were investigated.  Experimental parameters affecting biosorption process such as pH, contact time, biomass dosage and temperature were studied. Langmuir, Freundlich and Dubinin–Radushkevich (D–R) models were applied to describe the biosorption isotherms. Langmuir model fitted the equilibrium data better than the Freundlich isotherm.The biosorption capacity of biomass (opuntia ficus-indica) for total copper was found to be 56.69 mg/g at pH 5 and 1g biomass dosage, 60 min equilibrium time and 22°C. From the D–R isotherm model, the mean free energy was calculated as 6.24 kJ/mol, indicating that the biosorption of total copper was taken place by chysisorption. The calculated thermodynamic parameters (G°, H° and S°) showed that the biosorption of copper onto biomass (opuntia ficus-indica) was feasible, spontaneous and exothermic at 22–45°C. Kinetic evaluation    of experimental data showed that the biosorption processes of copper followed well pseudo-second-order kinetics.