Synthesis and evaluation of different adsorbents based on poly(methacrylic acid-trimethylolpropane trimethacrylate) and poly(vinylimidazole-trimethylolpropane trimethacrylate) for the adsorption of tebuthiuron from aqueous medium

In the present study a new cross-linked copolymer poly(methacrylic acid-trimethylolpropane trimethacrylate) (named PMA) and poly(vinylimidazole-trimethylolpropane trimethacrylate) (named PVI) was synthesized through precipitation polymerization and applied to the adsorption of tebuthiuron. Adsorbent materials were characterized by using FT-IR, SEM, TGA, textural data, and elemental analysis. Kinetic study showed that the tebuthiuron adsorption was very quick and the equilibrium time was achieved at 20 min for both polymers. Experimental kinetic data for both polymers were very well described by the second-order kinetic model, thus indicating that tebuthiuron adsorption involves chemical adsorption in different binding sites, which could control the reaction rate. Adsorption equilibrium data were better fitted to the dual-site Langmuir-Freundlich model, which recognizes the existence of two kinds of adsorption sites on the polymer surface ascribed to the presence of carboxyl and carbonyl groups from PMA and imidazole ring and carbonyl group from PVI. The maximum adsorption capacities of PMA and PVI were found to be 186.76 and 213.89 mg g− 1, respectively, which are much higher than other adsorbents.