Equilibrium, kinetic, diffusion and thermodynamic applications for dye adsorption with pine cone

ABSTRACT

In the present study, the adsorption of methylene blue onto pine cone was investigated. Adsorbent was characterized by XRD and SEM. The adsorption data follow the Langmuir isotherm model. Maximum adsorption capacity was calculated 125 mg.g⁻¹ . It was determined that the pseudo-second-order model was the best choice among all the available kinetic models to describe the adsorption behaviour. E_a was found to be 19.57 kJ mol^−1. This confirms the fact that the adsorption was a physical process. The negative free energy values indicate the feasibility of the adsorption process and its spontaneous nature.

KEYWORDS:

• Methylene blue
• pine cone
• adsorption kinetics
• diffusion
• thermodynamic