Investigations and characterization of radiation grafted copolymers for possible practical use in waste water treatment

Selective removal and recovery of metals from industrial effluent is an env ironmental problem and economic concern. There are a number of heavy metals that are candidates for removal prior to having waste solutions coming in contact with the environment. Therefore, a study has been made on the prepa ration of hydrophilic membranes having both anionic and cationic exchangers . To achieve such properties in the required membranes, a trial has been ma de on the radiation graft copolymerization of binary monomers possessing an ionic and cationic exchangers such as acrylic acid/2- and 4-vinyl pyridine (AAc/2-VP) (AAc/4-VP) onto available commercial polymeric substrate such as low-density polyethylene (LDPE). The preparation conditions at which the g rafting process proceeds homogeneously are determined. Characterization and some selected properties of the prepared grafted membranes were studied an d accordingly the possibility of its practicable use in waste water treatme nt from heavy and toxic metals such as Pb, Zn, Cd, Fe,... etc, was investig ated. The metal uptake by such prepared membranes was determined by using a tomic absorption technique. The membrane efficiency and durability was inve stigated. The maximum uptake for a given metal was higher for the LDPE-g-P (AAc/2VP) membranes than that for the LDPE-g-P (AAc/4VP). The chelated meta l ions were easily desorbed by treating the membrane with 0.1 N HCl for 2 h at room temperature. A mixture of two or three metals in the same feed sol ution was used to determine the selectivity of the membrane towards differe nt metals. The results obtained for the prepared membranes showed a great p romise for their applicability in the removal of heavy metals from wastewat er. (C) 1999 Elsevier Science Ltd. All rights reserved.