Separation and Purification Technology 57 (2007) 329–337 Removal of phenolic compounds using (2-hydroxyethyl methacrylate/acrylamidopyridine) hydrogel prepared by gamma radiation Hany El-Hamshary a,∗ , Samia El-Sigeny b , Manal F. Abou Taleb c,∗ , Nabil A. El-Kelesh c a Department of Chemistry, Faculty of Science, Tanta University, Tanta 31527, Egypt b Chemistry and Physics Department, Faculty of Education at Kafr El-Sheikh, Tanta University, Egypt c National Center for Radiation Research and Technology, P.O. Box 29, Nasr City, Cairo, Egypt Received 9 January 2007; received in revised form 8 April 2007; accepted 8 April 2007 Abstract Hydrophilic copolymers of 2-acrylamidopyridine (AP) and 2-hydroxyethylmethacrylate (HEMA) with different molar ratios were prepared by gamma irradiation-induced copolymerization using 60 Co 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. © 2007 Elsevier B.V. All rights reserved. Keywords: Radiation; Poly(HEMA/AP); Phenolic compounds; Adsorption; Copolymerization 1. Introduction Phenolic compounds constitute an important class of organic contaminants commonly found in the subsurface. Phenolic com- pounds are present in the wastewater of many phenol-producing industries such as: fertilizer, pesticide, pharmaceutical, dye manufacturing, oil refineries and coal conversion process indus- tries, etc. [1–6]. Phenolic compounds may also come to the environment through the agricultural runoff and domestic waste [7]. The production of phenols and related chemicals, are listed among the 25 most frequently detected groundwater contami- nants at hazardous waste sites [8]. Phenolic compounds are water soluble and highly mobile and hence are likely to reach drinking water sources downstream from discharges, where, even at low concentrations, they can cause severe odor and taste problems and pose risks to populations. ∗ Corresponding authors. Tel.: +20 2 2749298; fax: +20 2 2749298. E-mail addresses: Hany elhamshary@tanta.edu.eg (H. El-Hamshary), abutalib m@yahoo.com (M.F. Abou Taleb). For the removal of phenolic compounds from aqueous solu- tion, various treatment technologies such as adsorption over granular activated carbon and fibrous activated carbon [9], zinc oxide, alumina pillared clays, mesoporous alumina-aluminium phosphates; [10], synthetic polymers [11,12] and ion exchange resins [13,14] have been used. Phenol removal through oxidative coupling polymerization [15] and enzyme-catalyzed polyme- rization has been investigated as an alternate detoxification method [16]. With hydrogen peroxide, peroxidase catalyzes the oxidation of phenols to phenoxy radicals that undergo further non-enzymatic reactions generating various oligomers and poly- mers [17,18]. In recent years, electrochemical treatment has also been used intensively for the removal of phenol from wastewa- ters [19,20]. Among various physicochemical processes adsorption is widely used for the removal of phenol from wastewater [21,22]. Resins based on polymers of 2- and 4-vinylpyridines have been used successfully as supports for various reagents and catalysts for the oxidation and/or destruction of phenols [23–25]. The sorptive properties of 4-vinylpyridine-divinylbenzene [26] and N-vinylimidazole-divinylbenzene [27] copolymers were tested 1383-5866/$ – see front matter © 2007 Elsevier B.V. All rights reserved. doi:10.1016/j.seppur.2007.04.013