Removal of cobalt ions from aqueous solutions by using poly(N,N‐dimethylaminopropyl methacrylamide/itaconic acid) hydrogels

In this study, N,N‐dimethylaminopropyl methacrylamide (DMAPMAm) homopolymer and DMAPMAm/itaconic acid (DMAPMAm/IA) copolymers were obtained from ⁶⁰Co‐γ radiation polymerization. Gel fraction and percentage of swelling values were calculated through gravimetrical calculations. In order to increase the swelling of the hydrogel, the amount of IA in initial copolymer composition was gradually increased, but it was observed that gelation values were low. The structural and morphological assessments of homopolymer and copolymers were made by means of several techniques including Fourier Transform Infrared Spectroscopy (FT‐IR), Scanning Electron Microscopy (SEM), and Energy‐Dispersive X‐ray Spectroscopy (EDS). The cobalt ion (Co²⁺) removal capacities of hydrogel were investigated by taking into account of the initial metal ion concentration and pH of aqueous medium. When it came to the maximum capacity of values obtained from adsorption experiments by using Co²⁺ solutions at pH 5, they changed between 220 and 245 mg Co²⁺/g dry hydrogel. FT‐IR, SEM, EDS, and XRD analyses were carried out for enlightening the mechanism of Co²⁺ removal by hydrogels after the completion of adsorption. Also, desorption studies were conducted using ethylenediaminetetraacetic acid (EDTA). Finally, within approximately 5 days, all adsorbed Co²⁺ ions were released from hydrogels at pH 5 using 0.1M EDTA solution. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 39569.