Abstract
Heavy metals being the most common pollutants of water and soil pose a risk for the ecosystems due to their non-degradable nature. Especially, chromium (Cr) is widely used in metal plating, pigmentation, printing, textile dyeing, wood preservation and other industries, therefore being a very common pollutant in surface and underground waters. The elimination of such pollutants from wastewater is highly important because of their carcinogenic and toxic nature. Among many methods for the removal of Cr(VI) ions from wastewater, adsorption is the most common and effective physiochemical method, because of its high efficiency, recyclability, cost-effectiveness and simplicity. Polysaccharides have been extensively employed in synthesis of magnetic nanoparticles (MNPs) as coating materials for constructing an adsorptive material, mainly due to their high adsorptive ability and low-cost. They are also environmentally friendly, renewable, biodegradable, biocompatible and can easily be modified. Arabinogalactan (AG) is a polysaccharide, that has high adsorption capacity for Cr(VI) ions. AG modified magnetic nanoparticles (AG-MNPs) were prepared by co-precipitation method using ferric and ferrous ions and later used as the adsorptive material for efficient Cr(VI) removal. The optimum conditions for Cr(VI) ions adsorption were found to be at pH 4, with contact period of only 30 min at 200 rpm, resulting in 92.9% adsorption efficiency and 99.6% maximum adsorption efficiency after 120 min at 200 rpm, using Cr(VI) ions at concentration of 0.5, 1.0 and 5.0 mg/L.
