Synthesis of the Ion-Exchanger Based on 2-(diethylamino)ethyl Methacrylate-co-Ethyleneglycol Dimethacrylate Beads: Physico-Chemical Characterization and Chromatographic Performance for Sulfonamide Adsorption

Abstract

Sulfonamide antibiotics are persistent pollutants of aquatic environments, known to induce high levels of bacterial resistance and potential human health and ecological risks. We synthesized copolymeric beads of 2-(diethylamino)ethyl methacrylate-co-ethyleneglycol dimethacrylate (DEAEM-co-EGDMA) and further conducted batch and column-packed experiments to systematically examine their adsorption properties toward sulfamethoxazole, the sulfonamide most frequently detected in municipal sewage. The polymeric beads were obtained by suspension polymerization of a monomer mixture consisting of 40% DEAEM and 60% EGDMA dissolved in acetonitrile (ACN). Polyvinylpyrrolidone (PVP) was used as stabilizer of the suspension system. Cyclohexanol and poly(ethylene glycol) (PEG) of 1 kDa were used as porogens. Physical characterization showed that the polymers consist of macroporous micro spheres exhibiting a unimodal particle size distribution and good thermal stability. The copolymer showed very good retention capacity, 101 mg SMX/g wet resin, which is equivalent to 220 mg SMX/g dry resin. The Langmuir model described the successful SMX removal. Equilibrium and kinetic parameters were determined using the pore diffusion model. Several cycles of loading and elution were performed in a fixed bed column. Total SMX recovery was achieved in all elution cycles. The resin showed good performance to concentrate the antibiotic in the initial stages of elution, thus facilitating the removal of this compound.