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

The performance of poly(CGMAPEI), an amine-type chelating adsorbent synthesized by graft polymerization, was evaluated in a simulated waste stream containing Cu 2+ and Co 2+ heavy metal ions and NaNO 3 salt. Comparisons of metal adsorption curves of this adsorbent with a previously synthesized cellulose-PEI and commercially available chitosan-polyamine and amberlite resins were made. The poly(CGMAPEI) exhibited the highest capacity in the absence of NaNO 3 . At high concentrations of NaNO 3 , the affinities of all the amine-type adsorbents were found to be enhanced quite tremendously. The chelating adsorbent with the highest amine content (CS-03) showed the highest improvement in capacity. This phenomenon was not observed with the ion-exchanger (amberlite IRC 50) studied. Sodium ions showed negligible affinity for poly(CGMAPEI). Competition between Na + with Cu 2+ for adsorption sites in the adsorbent was absent. Regeneration experiments revealed some reduction in Cu 2+ affinity of poly(CGMAPEI) after acid treatment. Difficulty in stripping Co 2+ from poly(CGMAPEI) even by strong acid was also observed.