Heavy metal sequestration properties of a new amine-type chelating adsorbent

The performance of poly(CGMAPEI), an amine-type chelating adsorbent synthes ized by graft polymerization, was evaluated in a simulated waste stream con taining Cu2+ and Co2+ heavy metal ions and NaNO3 salt. Comparisons of metal adsorption curves of this adsorbent with a previously synthesized cellulos e-PEI and commercially available chitosan-polyamine and amberlite resins we re made. The poly(CGMAPEI) exhibited the highest capacity in the absence of NaNO3. At high concentrations of NaNO3, the affinities of all the amine-ty pe adsorbents were found to be enhanced quite tremendously. The chelating a dsorbent with the highest amine content (CS-03) showed the highest improvem ent in capacity. This phenomenon was not observed with the ion-exchanger (a mberlite IRC 50) studied. Sodium ions showed negligible affinity for poly(C GMAPEI). Competition between Na+ with Cu2+ for adsorption sites in the adso rbent was absent. Regeneration experiments revealed some reduction in Cu2affinity of poly(CGMAPEI) after acid treatment. Difficulty in stripping Co2 + from poly(CGMAPEI) even by strong acid was also observed. (C) 1998 Publis hed by Elsevier Science Ltd. All rights reserved.