Résumé
This study targets betaine-type polymers (polycarbobetaines - PCBets) as complexing agent of metal ions. As PCBets are pH-sensitive, the adsorption isotherms of copper onto PCBet were monitored at various pH (from 3 to 6) by electrochemical measurements. The best fit to the Langmuir model translates the predominantly homogeneous distribution of the chelating groups on the polymer chains because the Langmuir equation assumes that the adsorbent surface is energetically homogeneous. The results obtained for the complexation of copper were greatly enhanced as the pH increase and reached 250 ± 10 mg g−1 at pH = 6. Such maximal adsorption capacities compete with recent results obtained for molecules of environmental interest such as chitosan, for example. The copper adsorption efficiency was shown stable for soft to hard water. The selectivity of the target PCBets for copper was indicated in the presence of nickel, cobalt, manganese, zinc, calcium or magnesium and partially accounts for the interest in this material and demonstrated the relevance of using PCBet in environmental applications such as copper recovery. The reusability of PCBet was explored by pH adjustment. The results confirm that the efficiency of copper adsorption was maintained over five cycles of PCBet reuse (99 ± 3%). A full process for copper recovery was then designed at laboratory scale for copper recovery from synthetic wastewaters.