Adsorption of Methyl Violet Dye onto Cresson Seeds: Thermodynamic and Kinetic Studies

摘要

The adsorption of methyl violet dye onto Cresson (Lepidium sativum) seeds also known as Garden cress as an adsorbent from its aqueous solution has been carried out. The effect of experimental coefficient parameters like connection time, primary concentration of adsorbate (methyl violet) and amount of adsorbent dose and temperature were evaluated to obtain the optimum condition for adsorption of methyl violet onto Cresson seeds using batch adsorption. The adsorption information were mathematically analyzed using adsorption isotherms like Langmuir, Freundlich and Dubinin-Radushkevich isotherms in order to study adsorption mechanism of methyl violet dye onto Cresson seed. The isotherms of adsorption were advanced and equilibrium data adjusted well to Freundlich isotherm model. The kinetic studies indicated that the process of adsorption followed the model of second-order kinetic. The thermodynamic parameters (ΔG°, ΔH° and ΔS°) were estimated and the obtained negative value of ΔG° indicate a spontaneous adsorption process, positive ΔH° value obtained designate about the endothermic properties of adsorption process and positive ΔS° value obtained during the adsorption indicated the increased randomness.