The main parameters affecting PEUF are metal and polymer type, the ratio of metal to polymer, pH and existence of other metal ions in the solution. Molinari et al. (2008) used PEI as a polymer to study the complexationeultrafiltration process in the selective removal of Cu(II) from Ni(II) contained in aqueous media. Preliminary tests showed that optimal chemical conditions for Cu(II) and Ni(II) complexation by the PEI were pH > 6.0 and 8.0, respectively, and polymer/metal weight ratio of 3.0 and 6.0, respectively. Aroua et al. (2007) investigated the removal of chromium species from aqueous dilute solutions using PEUF process by three water-soluble polymers, namely chitosan, PEI and pectin. High rejections approaching 100% for Cr(III) were obtained at pH higher than 7 for the three tested polymers.