Biosorption of Cu2+ in a packed bed column by almond shell: optimization of process variables

This paper presents the ability of a low-cost biosorbent, almond shell, to remove Cu(II) ions from aqueous solution. Biosorption capacity of almond shell to removal Cu(II) was studied in a packed bed column. The effect of various parameters, flow rate, initial copper concentration, and mass of biosorbent, was analyzed. A 2(3) factorial experiment design was carried out to optimize some of the factors directly affecting the biosorption of copper onto almond shell. The results have shown that initial concentration of Cu(II) is the most influential factors in biosorption capacity, while the most important factors in total copper removal are the flow rate and mass of biosorbent. The biosorption capacity of almond shell presented a maximum when the operational conditions are: flow rate, 6 mL/min; initial copper concentration, 100 mg/L; and mass of almond shell, 5 g; while the parameters which give the maximum value of % removal of Cu(II) are: flow rate, 2 mL/min; initial copper concentration, 40 mg/L; and mass of biosorbent, 15 g. The experimental breakthrough curves obtained under optimum conditions were modeled using Bohart-Adams, Thomas, Yoon-Nelson, and dose-response models. The Bohart-Adams model was valid only in representing the initial part of the breakthrough curves. The dose-response model is acceptable to reproduce the breakthrough curves.