Cadmium Removal from Aqueous Solutions by Magnetic Iron Oxide Bio Adsorbents



Heavy metals in the water resources are one of the most important environmental problems of human societies. Up to now, various methods were considered for removal of heavy metals, which among them using of low cost adsorbents are more favorite but, separation of them from process is so difficult. In this study a novel magnetic adsorbent based on orange peel and iron oxides composite was synthesized and used for removal of cadmium ions from aqueous solution. Dry orange peels were milled and granulated in 0.125-0.250 mm by standard sieves. Magnetic iron oxide particles was separately synthesized and allowed to combine with granulated orange peels. Batch equilibrium absorption experiments were carried out at various initial Cd ion concentrations, contact times and adsorption dosages in constant temperature and pHzpc. At the end of each adsorption experiment, the separation of adsorbents from aqueous solution was performed by a magnetic bar. The results showed the magnetic orange peel iron oxide adsorbents had a high efficiency for adsorption of cadmium from aqueous solutions. The experimental adsorption isotherm of cadmium on magnetic orange peel adsorbents were determined and correlated with common isotherm equations such as Langmuir, Freundlich and Temkin models. The results indicated the Freundlich isotherm model was the best model for fitting the adsorption data.