Use of polyethylene films photografted with 2-(dimethylamino)ethyl methacrylate as a potential adsorbent for removal of chromium (VI) from aqueous medium

A new polymeric adsorbent material based on polyethylene (PE) was prepared by photografting of 2-(dimethylamino)ethyl methacrylate (DMAEMA) as a positively chargeable monomer to a PE film. The effects of the experimental parameters, such as the pH value, temperature, and grafted amount on adsorption of chromium(VI) (Cr(VI)) ions were investigated for the DMAEMA-grafted PE (PE-g-PDAMEMA) films. The maximum adsorption capacity was obtained at the initial pH value of 3.0 for a PE-g-PDMAEMA film with 1.8 mmol/g and the maximum adsorption capacity obtained was higher than or compatible to those of many of the other polymeric adsorbents prepared for Cr(VI) ions. The adsorption kinetics obeyed the mechanism of the pseudo-second order kinetic model and adsorption of Cr(VI) ions on PE-g-PDMAEMA films was well expressed by the Langmuir isotherm model. A high Langmuir adsorption constant suggests that the adsorption of Cr(VI) ions occurs between protonated dimethylamino groups and ions mainly through the electrostatic interaction. Cr(VI) ions adsorbed were successfully desorbed from a PE-g-PDMAEMA film in solutions of NaCl, NH4Cl, NH4Cl containing NaOH, and NaOH and a PE-g-PDMAEMA film was regenerated and repeatedly used for adsorption of Cr(VI) ions without appreciable loss in the adsorption capacity. (c) 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43360.