Adsorption modeling of alizarin yellow on Biosorbent casuarina equisetifolla

Abstract

Adsorption studies of alizarin yellow from an aqueous solution were carried out on casuarina equisetifolla. Casuarina equisetifolla was subjected to various pretreatments. Various parameters such as pH, dosage amount, and contact time were studied to evaluate the adsorption behavior. Langmuir, Freundlich, Temkin, Harkin-Jura, and Halsey isotherm models were used to explain the experimental findings. The Freundlich model was best fitted, pointing out multilayer adsorption. Thermodynamic parameters such as ΔG◦, ΔH◦, and ΔS◦ were also calculated, which showed that a spontaneous and favorable reaction occurred for casuarina equisetifolla. The positive values of ΔH◦ for biosorbent indicate that the adsorption mechanism was endothermic. From the Arrhenius equation, parameter E was equal to 19.1414kJ mol ⁻1, which corroborated the temperature dependency of the rate of adsorption.