Adsorption Characteristics of Chrysophyllum albidum (African Star Apple) Peels Towards Heavy Metal Ions

Currently the use of agricultural waste as a low-cost adsorbent have attracted much attention of researchers. The removal of cadmium (II), copper (II) and lead (II) ions from aqueous solution using peels of Chrysophyllum albidum (African Star Apple) was studied. The sorption studies were carried out by varying adsorbent dose, contact time and temperature. The experimental results showed that the adsorption removal efficiency of Chrysophyllum albidum peels on cadmium (II), copper (II) and lead (II) ions had a direct relationship with adsorbent dose and contact time while the Temperature study showed an inverse relationship. The maximum adsorption efficiencies of the adsorbent were ۹۵.۳۰, ۹۳.۲۲ and ۹۲.۷۸ % for Cd۲+, Cu۲+ and Pb۲+ respectively. Sorption kinetic data fitted well with the pseudo second order kinetic model. The experimental data were analyzed using Freundlich, Langmuir and Temkin isotherm equations. The best fit was obtained by Temkin isotherm for Cd۲+ and Freundlich isotherm for Cu۲+ and Pb۲+ ions. The Arrhenius and Eyring activation energy showed that rate of Cd۲+ adsorption is more rapid than rate of Cu۲+ and Pb۲+ adsorption. The thermodynamic data revealed that the Cd(II) and Pb(II) ion uptake was exothermic while Cu(II) ion was endothermic and they were all spontaneous in nature. From these results, Chrysophyllum albidum peel could be recommended as an adsorbent for metal ion removal from aqueous solution.

کلیدواژه ها:

Biomaterial ، Adsorption ، Metal ions ، Kinetics ، Thermodynamics ، Isotherms