Imidazolium Salt Incorporated Poly(N-vinylimidazole-co-ethylene glycol dimethacrylate) for Efficient Adsorption of Congo Red and Hg2+ from Aqueous Solution

Herein, imidazolium salt incorporated poly(N-vinylimidazole-co-ethylene glycol dimethacrylate) was developed for adsorption of Congo Red (CR) and Hg2+ from aqueous solution. By the introduction of N-vinylimidazole and p-dichloroxylene on the skeletons, this polymer contained not only ionized imidazole moieties but also plenty of mesopores, endowing the polymer with excellent adsorption of CR and Hg2+. The maximum capacity at 298 K reached 503.0 and 240.0 mg/g, respectively. The Langmuir model described the equilibrium data well, and a chemical interaction in forms of electrostatic interaction, hydrogen bonding, and chelating interaction was involved in the adsorption with adsorption enthalpies of 9.99 and 17.28 kJ/mol, respectively. The adsorption was a fast process, and less than 20 min was sufficient to attain the equilibrium with pseudo-second-order rate constants of 4.003 × 10–3 and 9.830 × 10–4 g/(mg·min), respectively.