Removal of heavy metals by biopolymer (chitosan)/nanoclay composites

More recently, polymer/inorganic hybrid adsorbents have emerged new class of adsorbents for deep removal of trace pollutants and among them chitosan is a natural biodegradable and non-toxic polysaccharide. Natural clay minerals with properties like abundance in most continents of the world, high sorption properties, potential for ion exchange, and with their low cost, are strong candidates as adsorbents. In this study, chitosan/nanoclay composites were developed by using surfactant-clay (organo-clay) and chitosan biopolymer and synthesized by polymerization method. Fourier transform infrared spectroscopy, X-ray diffraction, thermal gravimetric analysis and sorptometric analysis characterized the porous chitosan/nanoclay composites. The adsorption of copper (II) and Nickel (II) ions onto the prepared chitosan/nanoclay composites from an aqueous solution using batch adsorption was examined. The results showed that benefiting from the surface property of clay, the abundant amino and hydroxyl functional groups of chitosan, the adsorbent provides adequate and versatile adsorption for the Cu (II) and Ni (II) ions under investigation. The best adsorption capacities were obtained as 176 mg/g and 144 mg/g for Cu and Ni, respectively. These values are higher than obtained ones (135 mg/g for Cu and 65 mg/g for Ni) in the literature up to now.