Heavy Metals Removal from Wastewater Using a Versatile Branched Polymer: Carboxylated Polyethylenimine (PEI-COOH)

The presence in the environment of large quantities of toxic heavy metals (i.e. cobalt, cromium, lead, cadmium, zinc, etc.), poses serious health risks to individuals, hence the development of novel methods to eliminate toxic contaminants from wastewaters in efficient and economically viable ways is highly desirable. In this work we assayed the ability of a polyamine polymer, polyethylenimine (PEI) and its carboxylated derivative PEI-COOH to complex a selection of twenty two heavy metals and remove them from a contaminated water by an ultra-filtration technique. We found that PEI is able to complex efficiently and reduce the concentration of eleven heavy metals (Ag, Al, Cd, Co, Cr, Cu, Mn, Ni, Pb, Sn and Zn) to almost a third. In some cases, PEI is very efficient to remove also Cr and Sn to a concentration less than 0.1 ppm. Interestingly, PEI-COOH derivative is able to remove eight heavy metals (Ag, Al, Cd, Co, Cu, Ni, Pb, and Zn) to a concentration less than 0.4 ppm hence incr