ABSTRACT:The water-soluble polymers poly(styrene sulfonic acid-co-maleic acid) and poly(acrylic acid-co-maleic acid) were investigated with respect to their metal-ion-binding ability with ultrafiltration. The studied metal ions included Ag(I), Cu(II), Ni(II), Co(II), Ca(II), Mg(II), Pb(II), Cd(II), Zn(II), Al(III), and Cr(III) ions. The retention properties of the polyelectrolytes for the metal ions depended strongly on the ligand type. As for the carboxylate ligands, with increasing concentration and pH, the metal-binding affinity increased.
ABSTRACT:The commercial polymers poly(ethylene imine) (PEI), poly(ethylene imine epichlorohydrin), and poly(dimethylamine-co-epichlorohydrin) were purified and fractionated by ultrafiltration. Their metal-ion-binding properties with respect to different ligand groups and the effect of the concentration on the retention properties were investigated. The amine ligands of the polymers formed the most stable complexes with the metal ions. In general, there was an effect of the pH and polymer fraction size on the retention properties. As the pH and polymer fraction size increased, the affinity to bind metal ions also increased. PEI had the highest metal-retention values, particularly at higher pHs, at which the amine groups were nonprotonated and could coordinate easily with the metal ions. Only Pb(II) was poorly retained. The affinity for all the metal ions, except Pb(II), increased significantly at pH 5. The metal-ion retention decreased quickly as the filtration factor increased, except for Cu(II), Co(II), Ni(II), Cd(II), and Zn(II) ions, which were retained by over 40% at a filtration factor of 4. For other metal ions such as Pb(II), Ca(II), and Mg(II), only 10% remained bound to the polymer.
Commercial, water-soluble poly(ethylenealt-maleic anhydride), P(E-alt-MAn), was quantitatively hydrolyzed by 0.2M NaOH to yield poly(ethylene-alt-maleic acid), P(E-alt-MAc). The polymer structure is confirmed by FT-IR spectroscopy. As the pH increases, metal ion affinity increases because the majority of the functional groups are present as carboxylate anions, which can form more stable complexes at a higher pH. By increasing the filtration factor, Z, metal ion affinity does not significantly decrease, which means that the ligand-metal interaction is strong and cannot be destroyed by washing with water at the filtration cell's pH.
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 ligandmetal interaction was strong, and it is not possible to break it by washing with water at the same pH of the filtration cell.Water-soluble polymer materials 869 conditions to recover the polychelatogen and investigate their ability to remove the metal ions after these treatments.
Water-soluble poly [3-(dimethylamino)propylacrylate] is synthesized by radical polymerization with a yield of 87%. The polymer structure is confirmed by FT-IR and 1 H-NMR spectroscopies. The polymer lost only 3% of weight up to 100 8C. The narrowest molecular weight distribution is observed with the fraction between 3,000 and 10,000 Da. P(DAPA) presents a high affinity for the metal ions Pb 2þ and Cu 2þ , while the other metal ions are not significantly retained. By increasing the filtration factor, Z, metal ion affinity decreases, indicating a very weak ligand-metal interaction and the possibility of its destruction when washed with water at the filtration cell's pH. For Z ¼ 10, the retention values of Pb 2þ and Cu 2þ at pH 5 are 76.5% and 48.5%, respectively, while the values for Cu 2þ and Cd 2þ at pH 7 are 89.5% and 40.4%, respectively.
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