Characterization of persimmon fruit peel and its biochar for removal of methylene blue from aqueous solutions: thermodynamic, kinetic and isotherm studies

The persimmon fruit peel (PFP) and its biochar (PFP-P) were evaluated for removal of methylene blue (MB) from aqueous solutions and characterized in detail. The pyrolysis of the PFP improved carbon content, surface area, and surface electronegativity of the biochar produced. The effect of initial solution pH, initial MB concentration, contact time, and temperature on the biosorption efficiency of MB on the PFP was investigated through the biosorption experiments in a batch system. The PFP showed higher biosorption removal efficiency than PFP-P due to the existence of hydroxyl and carboxyl functional groups. The maximum biosorption capacity of the PFP was found using 2 g/L of the adsorbent, at a contact time of 180 min and pH of 7. The adsorption kinetics and equilibrium isotherms were well represented by the pseudo-second-order model and the Langmuir model, respectively. The maximum biosorption capacity obtained from the Langmuir isotherm model was 303 mg g(-)(1). Also, the PFP showed an efficient removal efficiency for removal of MB in tap water, seawater, and river water. The high MB biosorption capacity of PFP can be a promising alternative for cationic dye removal at neutral pH.