Sorption of basic dye from aqueous solution by pomelo (Citrus grandis) peel in a batch system

A new, low-cost, locally available sorbent, pomelo (Citrus grandis) peel (PP), was tested for its ability to remove basic dye (methylene blue) from aqueous solutions. Adsorption equilibrium and kinetics of methylene blue (MB) from aqueous on PP were studied in a batch process. The equilibrium data were analyzed using the Langmuir, Freundlich, and Temkin isotherm models. Sorption equilibrium studies demonstrated that the biosorption followed Langmuir isotherm model. The monolayer adsorption capacity was 344.83 mg/g at 30 °C. Kinetic analyses were conducted using pseudo-first-, second-order and intraparticle diffusion models. It was found that the sorption kinetics of MB on PP obeyed pseudo-second-order sorption kinetics. The results in this study indicated that pomelo peel was an attractive candidate for removing MB from aqueous solutions.