Removal of phenolic compounds using (2-hydroxyethyl methacrylate/acrylamidopyridine) hydrogel prepared by gamma radiation

Hydrophilic copolymers of 2-acrylamidopyridine (AP) and 2-hydroxyethylmethacrylate (HEMA) with different molar ratios were prepared by gamma irradiation-induced copolymerization using ⁶⁰Co gamma rays of 20 wt.% aqueous solutions of monomer mixtures. The prepared polymers were characterized by FTIR, NMR and TGA analysis. The capacities for the adsorption of phenolic compounds onto the copolymers were found to be 26.7, 12.5 and 8.5 mg/g polymer for phenol, 2,6-dimethylphenol (DMP) and 2,6-di-t-butylphenol (DBP), respectively, using 20% AP copolymer. When the ratio of AP increased to 50% in the copolymer composition the amount of the above mention phenols retained increased significantly to be 35.1, 30.1 and 17.2 mg/g polymer for phenol, 2,6-dimethylphenol (DMP) and 2,6-di-t-butylphenol (DBP), respectively. Increasing the pH of the medium resulted in increasing of the amount of adsorbed phenols by the polymers. The kinetics of the adsorption at different concentration was also investigated.