HEAVY METAL SEQUESTRATION PROPERTIES OF A NEW AMINE-TYPE CHELATING ADSORBENT

摘要

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.