Some results on metal ions removal from wastewaters using water-soluble polymers such as polyethylenimine(PEI), polyacrylic acid (PAA), polyacrylic acid sodium salt (PAASS) and poly(dimethylamine-co-epichlorohydrin-coethylene-diamine) (PDEHED) as chelating agents and the Cu2+ ion as the model in combination with a polymer-assistedultrafiltration process (PAUF) are reported. In particular, the performances of these polymers in Cu2+ removal fromwastewaters were compared. Tests of bonding capacity and best operating conditions of the process showed thatcomplexation conditions depend on pH; indeed, copper ions are complexed by PEI, PAA, PAASS and PDEHED atpHs higher than 6, 4.6, 4.6 and 8, respectively. The decomplexation reactions took place at pH <3. Bonding capacitywas 0.333 mg Cu2+/mg polymer, meaning a ratio of polymer/Cu2+ = 3 (w/w) for PEI, PAA and PAASS. For thechelating agent PDEHED, a ratio of PDEHED/Cu2+ = 0.5 (w/w) was determined. UF tests, realized at two transmembranepressures (2 and 4 bar) by using five different flat-sheet membranes, showed that the PAA polymer and thePAN GKSS HV2/T membrane can be used when the objective of the purification process is to decrease metalconcentration not lower than a certain value. The PDEHED polymer is useful if the objective of wastewater treatmentis to obtain complete copper removal. Simple washings with tap water were enough for regeneration and reuse of themembranes.
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