Isotherm, Kinetic and Thermodynamic of Reactive Blue 5 (RB5) Dye Adsorption Using Fe3O4 Nanoparticles and Activated Carbon Magnetic Composite

In this study, magnetized activated carbon was synthesized due to quick and easy separation and no secondary pollution in solution, and was used as an adsorbent for the removal of Reactive Blue (RB5) from aqueous solution. Physical, surface and morphological properties of the synthesized adsorbent were analyzed by XRD, SEM, EDX, TEM and BET techniques. Furthermore, the efficiency of the adsorbent in removal of dye in a batch system was studied by investigating the impact of different parameters such as pH, contact time, adsorbent dosage, initial dye concentration and solution temperature. Langmuir and Freundlich isotherms and two models kinetically of pseudo first-order and pseudo second-order were used to investigate the experimental data. Results showed that at an optimum pH of 3 and an equilibrium time of 15 minutes, adsorption efficiency increases with increasing temperature and the amount of adsorbent used and decrease in the initial dye concentration. Results from studying the isotherms and kinetics of adsorption indicated that adsorption process follows Lungmuir isotherm (R2>0.999) and the kinetic model of pseudo second-order (R2>0.995). The maximum adsorption capacity was calculated 250 mg/g under optimum conditions based on Langmuir isotherm. Also, the calculated values from thermodynamic parameters showed that the adsorption of RB5 on AC-Fe3O4 is endothermic and spontaneous.