Chitosan was utilized as adsorbent to remove methyl orange (MO) from aqueous solution by adsorption.
Batch experiments were conducted to study the effects of pH, initial concentration of adsorbate and tem-
perature on dye adsorption. The kinetic data obtained from different batch experiments were analyzed using
both pseudo first-order and pseudo second-order equations. The equilibrium adsorption data were analyzed
by using the Freundlich and Langmuir models. The best results were achieved with the pseudo second-order
kinetic model and with the Langmuir isotherm equilibrium model. The equilibrium adsorption capacity (qe)
increases with increasing the initial concentration of dye and with decreasing pH. The values of qe were
found to be slightly increased with increasing solution temperatures. The activation energy (Ea) of sorption
kinetics was found to be 10.41 kJ/mol. Thermodynamic parameters such as change in free energy (G), en-
thalpy () and entropy (S) were also discussed.