Influence de la complexation sur le transfert des cations en osmose inverse

The influence of complexation by different ligands on the transfer of metallic cations in reverse osmosis has been studied by using membranes composed of aromatic polyamides. In spite of the large volume increase of the diffusing solute, the addition of a complexant can significantly improve the transfer of metallic cations through a reverse osmosis membrane. The most important factor in the improvement of the transfer is the solubility in the membrane of the complexes created. This solubility is linked to the possibility of creating hydrogen bonds between the membrane and the complex. Moreover, the addition of substances which strongly solvate both the membrane and the solute leads to an improvement of transfer which increases considerably with the increasing pressure. These results suggest the possibility of separating metal cations by specific complexation.