Ion-exchange resin has been considered as a suitable material for the recovery of heavy metals in water treatment. The chelating group, iminodiacetic acid (-R-N(CH2COOH)2), was introduced into the weak-acid type (-R(COOH)-)-) ion-exchange resin to obtain bifunctional ion-exchange resins. Chromic, cupric, cadmium and lead ions were employed for adsorption experiments in this study. In isothermal experiments, the order of heavy metal ion adsorption decreased with increasing diameter of the heavy metal ion when the chelating group content was less than half. On the contrary, the adsorbed amount of lead ion would be higher than that of cadmic ion as the quantity of chelating group content was more than half owing to the stability constant difference (Ks[Pb2+] = 1017.5 > Ks[Cd2+] = 105.71 in iminodiacetic acid). The adsorption efficiency of bifunctional ion-exchange resins, especially for lead ions, would increase with rising chelating group content (from 0.08 mmol/mmol COOH to 0.31 mmol/mmol COOH). Meanwhile, the working pH range for metal ion adsorption in bifunctional ion-exchange resins was extended from 2.5 down to 0.5. Addition of chelating groups to weak acid ion-exchange resins could increase the adsorption efficiency for metal ions owing to the increased free volume of polymer structure.
|頁（從 - 到）||882-890|
|期刊||Macromolecular Chemistry and Physics|
|出版狀態||Published - 2001 4月 18|
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