Adsorption of basic dye onto activated carbon prepared from Palm Tree flower (Borassus flabellifer): Kinetics, equilibrium study and mathematical model

Adsorption experiments were carried out for the removal of Methylene blue (MB) using Palm Tree Male flower activated carbon (PTMFAC) as the adsorbent at various temperature, adsorbent and adsorbate concentration. The kinetic data were fitted in pseudo-first order, second order models. The equilibrium data were well fitted in Langmuir isotherm and the maximum equilibrium capacities of the adsorbent were found to be 541.2, 550.4, 588.2 mg/g at 303, 313, and 323 K, respectively. Thermodynamic data for the adsorption system indicated spontaneous and endothermic process. The enthalpy and entropy values for adsorption were obtained as 10.5 KJ/ mol and 0.113 KJ/ mol K respectively in the temperature range of 303-323 K. A new mathematical model for MB transported by molecular diffusion from the bulk of the solution to the surface of PTMFAC was derived and the values of liquid phase diffusivity and external mass transfer coefficient were estimated.