Ultrafiltration—Complexation in Wastewater Treatment
Waste Water Treatment
Published Online: 15 JUL 2005
Copyright © 2005 by John Wiley & Sons, Inc.
How to Cite
Molinari, R. and Argurio, P. 2005. Ultrafiltration—Complexation in Wastewater Treatment. Water Encyclopedia. 1:916–922.
- Published Online: 15 JUL 2005
A process for removal of ions from wastewaters by using water soluble polymers such as polyetilenimine (PEI), polyacrylic acid (PAA), polyacrylic acid sodium salt (PAASS) and poly(dimethylamine–co–epichlorohydrin–co–ethylenediamine) (PDEHED) as chelating agents and the Cu2+ ion as model in combination with ultrafiltration membranes (PAUF process), is described.
The tests on the complexing agents, to establish the binding capacity and the best operating conditions of the process, showed that complexation conditions depend on pH: indeed, copper ion is complexed by PEI, PAA, PAASS and PDEHED at pHs higher than 6, 4.6, 4.6 and 8, respectively. The decomplexation reactions took place at pH < 3. Binding capacity was 0.333 mg Cu2+/mg polymer for PEI, PAA and PAASS. For the chelating agent PDEHED the ratio was 2. Ultrafiltration tests were realized at two transmembrane pressures (2 and 4 bar), by using five different membranes, to make a comparison of polymers and membranes performances, as flux and rejection. UF tests showed that the PAA polymer and the PAN membrane GKSS HV2/T can be used when the objective of the purification process is to decrease the metal concentration not lower than a certain value that is accepted for water reuse or fixed by law for water discharge. The polymer PDEHED is useful if the objective of wastewater treatment is to obtain a complete copper removal.
The described work shows: i) the importance to use optimal chemical conditions to obtain a maximum binding capacity of the polymer; ii) the role of different types of UF membranes in order to employ the PAUF process in metal ions removal from various types of wastewaters.
- wastewater treatments;
- membrane processes;
- membrane processes;
- removal of pollutants from waters;
- water remediation;
- metal removal from waters;
- metal recovery from waters;
- complexing polymer reuse