Adsorption behavior of methylene blue onto powdered Ziziphus lotus fruit peels and Avocado kernels seeds

Abstract

In this research, two agroforestry by‐products were used as adsorbents for the removal of methylene blue (MB), as a model dye, from aqueous solution. The Ziziphus lotus fruit peels (ZLP) and Avocado kernel seed (AKS) were dried and powdered to particles of sizes <125 μm. Adsorption study was carried out in batch mode under different condition by varying initial dye concentration, contact time, initial solution pH, adsorbent dosage and reaction temperature. Rate constants of the adsorption were calculated by kinetic measurements. Equilibrium data were correlated to Langmuir and Freundlich isotherm models. The best fit was obtained by Langmuir model with maximum monolayer adsorption capacities of 66.04 mg/g in the case of ZLP and 59.07 mg/g in the case of AKS. The surface properties of the adsorbents were characterized by FTIR spectroscopy, SEM‐EDX analysis and the point of zero charge.

Keywords

• Adsorption
• Ziziphus lotus fruit peels
• Avocado kernel seeds
• methylene blue
• Kinetics
• Equilibrium