Water‐soluble polymer materials as complexing reagents for the separation of metal ions using membrane filtration

The commercial, water‐soluble poly(sodium anetole sulfonate) (PAnS), poly(sodium vinylsulfonate) (PVS), and poly(sodium 4‐styrene sulfonate) (PStyS) were investigated as metal ion binding reagents using the liquid‐phase‐polymer‐based retention (LPR) technique. The retention profiles of the following metal ions: Co(II), Ni(II), Ca(II), Mg(II), Pb(II), Cd(II), Zn(II), Cr(III), and Cu(II) were obtained by the LPR technique at pH 3, 5, and 7, and by changing the filtration factor Z from 0 to 10. As the pH increased, the affinity towards the metal ions increased slightly. By increasing the filtration factor Z, the affinity for the metal ions did not decrease significantly. This means that the ligand–metal interaction was strong, and it is not possible to break it by washing with water at the same pH of the filtration cell.