Equilibrium Study of Methylene Blue Sorption from Aqueous Solutions by a Low-cost Waste Material: Almond Peel

In the present work, the usefulness of almond peel as a sorbent material has been investigated for the removal of methylene blue from synthetic aqueous solutions in batch conditions. Isotherm of dye sorption was measured. The influence of different experimental parameters such as: almond peel mass, particles size, temperature, initial pH of solution and NaCl concentration on this isotherm was studied. All these parameters played an important part in sorption phenomenon: the methylene blue sorption increased as these parameters increased. The optimum initial pH for the removal of dye was in the range 6-7. Equilibrium data were mathematically fitted to Langmuir and Freundlich isotherm equations. Langmuir model gave a good fit to the experimental data over the whole equilibrium dye concentrations range. A high dye sorption was observed by this sorbent material: a maximum sorption capacity about 113-140 mg/g was achieved depending on the experimental parameter tested.