Removal of heavy metals from water using polyvinylamine by polymer-enhanced ultrafiltration and flocculation

•PVAm was used for heavy metal removal by polymer enhanced ultrafiltration (PEUF).•Performance of PEUF was affected by the PVAm dosage.•Precipitation of PVAm–metal complexes in presence of sulfate anions.

This study deals with the removal of heavy metals (i.e., Co (II), Cu (II), Ni (II), Pb (II), Fe (III), Cd (II), Zn (II) and Mn (II)) from water with polymer-enhanced ultrafiltration using polyvinylamine (PVAm) as a complexing agent. At a PVAm dosage of 0.1 wt%, metal rejections as high as over 99% were achieved for Pb (II), Cu (II) and Fe (III). The coordination interactions between PVAm and the heavy metals were investigated using UV–vis spectral and conductometric analyses. It was shown that the performance of PEUF for metal rejection was related to the coordination interactions between PVAm and the heavy metals. It was also found that when divalent sulfate anions were present, the PVAm–metal complexes precipitated out of the solution at high metal concentrations. Thus PVAm could also be used as a flocculant for metal removal by flocculation.