Sorptive removal of heavy metals with nano-sized carbon immobilized alginate beads

A composite adsorbent prepared by immobilizing graphite nano-sized carbon in alginate beads (NCB) was used for the removal of Co(II) and Ni(II) from aqueous solution. Kinetic studies showed that adsorption process reached equilibrium within 8 h at an initial concentration of 10 mg/L and sorption process was well explained by pseudo second order kinetic model. The Freundlich isotherm model correlated well with the adsorption isotherms of Co(II) and Ni(II) onto NCBs. The experimental results showed that the removal of Co(II) and Ni(II) ions from the solution was likely due to ion exchange with calcium(II) ions present in the alginate beads. (C) 2014 The Korean Society of Industrial and Engineering Chemistry. Published by Elsevier B.V. All rights reserved.