Synthesis of N-Methylimidazolium Functionalized Strongly Basic Anion Exchange Resins for Adsorption of Cr(VI)

N -Methylimidazolium functionalized strongly basic anion exchange resins in the Cl − form (RCl) and SO 4 2− form (R 2 SO 4 ) were synthesized and employed for adsorption of Cr(VI) from aqueous solution. FT-IR and elementary analysis proved the structures of anion exchange resins and the content of functional groups. The gel-type strongly basic anion exchange resins had high thermal stability according to TGA and good chemical stability under the experimental conditions. The adsorption behaviors of Cr(VI) on RCl and R 2 SO 4 were studied using the batch technique. It was shown that adsorption equilibrium was reached rapidly within 60 min. The adsorption data for RCl and R 2 SO 4 were consistent with the Langmuir isotherm equation. The maximum adsorption capacities of RCl and R 2 SO 4 were 132 and 125 mg/g, respectively, with almost all active sites fully occupied. RCl and R 2 SO 4 could be used in the wide pH range 1−12 and were very suitable to remove Cr(VI) at a low concentration level. They also showed great preference to Cr(VI) compared to the other counterions. RCl was easily regenerated using the mixed solution of 0.3 mol/L NaOH and 0.3 mol/L NaCl, and retained nearly 100% of its orginal capacity during four cycles.