Effective Elimination of Methylene Blue by Biomass Activated Carbon of Pomegranate Peel: Nonlinear Adsorption Kinetics and Isotherms

Abstract

Materials and Methods: Characterization studies were conducted to study the properties of the activated carbon using XRD, SEM and FTIR techniques. The experimental experiments were conducted to investigate the impact of several variables, the most important of which are: contact time (0-180 min), initial concentration (50-150 mg/L), adsorbent dose (0.02-0.1 g), pH (3-11), volume solution (25-100 mL), and temperature (20- 50 °C).

Results: Adsorption isotherms represented by Langmuir and Freundlich models have different correlation factors, 0.9979 and 0.9114 respectively. Langmuir model analysis has proven to be the appropriate model to explain the process of adsorption of MB dye to the surface of the adsorbent, which naturally tends to form a single layer of the adsorbate dye on the surface of the activated carbon adsorbent. The maximum adsorption capacity was 116 mg/g. As for the study of kinetics, the pseudo-second order (R2 = 0.9995) reaction was the closest to representing the kinetics of dye adsorption on the surface. Thermodynamic parameters were evaluated, indicating that the adsorption is spontaneous and endothermic. In which the ∆°G, ∆°H and ∆°S were as follow: (-9.196 to -18.058 kJ/mol), 77.363 kJ/mol, and 0.2954 kJ/mol K.

Conclusion: In conclusion, pomegranate peel activated carbon has been proven to be an effective and inexpensive adsorbent used to remove methylene blue from wastewater.