Removal of Hg(2+) from Aqueous Solution Using a Novel Composite Carbon Adsorbent

Abstract

A novel composite carbon adsorbent (GCA) has been prepared by immobilizing activated carbon and genipin-crosslinked chitosan into calcium alginate gel beads via entrapment and applied to the removal of mercury (Hg(2+)) ions from aqueous solution (e.g., drinking water). Two bead sizes and two mixing ratios of components were obtained and characterized. Batch experiments were performed to study the Uptake equilibrium and kinetics, of Hg(2+) ions by the GCA. The Hg(2+) adsorption capacity of GCA was found to be dependent of pH and independent of size of the adsorbent. The Hg(2+) adsorption rate of GCA increases with decreasing its bead size. However, both adsorption capacity and rate of GCA for Hg(2+) increase with increasing its chitosan content. Otherwise, it was shown that the GCA has higher Hg(2+) adsorption capacity and rate than activated carbon, which might he caused by the incorporation of chitosan into the GCA. The maximum Hg(2+) adsorption capacity of GCA was found to be 576 mg/g, which is over seven times higher than that of activated carbon. Our results reveal the uniform distribution of activated carbon and chitosan within the alginate gel bead and that Hg(2+) ions can diffuse inside the bead. It also demonstrated the feasibility of using this GCA for Hg(2+) removal at low pH values. The Hg(2+) absorbed beads of the GCA can be effectivelY regenerated and reused using H(2)SO(4). (C) 2009 Wiley Periodicals, Inc. J Appl Polym Sci 112: 2445-2454, 2009