Egyptian Apricot Stone (Prunus armeniaca) as a Low Cost and Eco-friendly Biosorbent for Oxamyl Removal from Aqueous Solutions

In this work, activated carbon was prepared from apricot stone (ASAC) waste to remove the insecticide oxamyl from aqueous solutions. The effect of different parameters such as adsorbent dose, the initial oxamyl concentration and contact time were investigated. Adsorption isotherm, kinetics and thermodynamics of oxamyl on ASAC were studied. Equilibrium data were fitted to the Langmuir, Freundlich, Temkin and Dubinin-Radushkevich (D-R) isotherm models. Langmuir isotherm provided the best fit to the equilibrium data with maximum adsorption capacity of 147.05 (mg/g). Kinetic studies were also undertaken in terms of pseudo-first-order, pseudo-second-order and intraparticle diffusion kinetic models for oxamyl on ASAC. The adsorption process follows the pseudo-second order kinetic with high coefficients correlation. The thermodynamic parameters ∆Gº, ∆Hº and ∆Sº determined, showed that the adsorption of oxamyl onto ASAC was feasible, spontaneous and endothermic. The results showed that ASAC is an efficient adsorbent for the adsorptive removal of oxamyl from aqueous solutions