Application of Papaya Seeds as a Macro-/Mesoporous Biosorbent for the Removal of Large Pollutant Molecule from Aqueous Solution: Equilibrium, Kinetic, and Mechanism Studies

The potential use of papaya seeds as biosorbent for the removal of a large dye molecule, Procion Red, from aqueous solution was investigated. Papaya seeds were characterized by nitrogen adsorption/desorption isotherms and scanning electron microscopy. The results revealed that the papaya seeds exhibit a macro-/mesoporous structure, which is desirable for applications in adsorption processes. The models of Langmuir, Freundlich, and Temkin were employed to fit the equilibrium data, where the Langmuir model showed the most suitable fitting. The maximum adsorption capacity for Procion red dye was found to be 73.26mgg(-1). Pseudo-first-order, pseudo-second-order, Elovich, and intraparticle diffusion models were used to analyze the kinetic data obtained at different concentrations of dye. The adsorption process of Procion red dye followed the pseudo-second-order and intraparticle diffusion models. The results indicated that the adsorbent used in this work is adequate for the treatment of large dye molecules containing in aqueous solutions. This work highlights the potential application of papaya seeds in the field of adsorption.