Synthesis and characterization of imidazole-functionalized SBA-15 as an adsorbent of hexavalent chromium

Mesoporous SBA-15 was functionalized with imidazole groups by a facile two-step post-grafting method. The resultant material has been characterized by powder X-ray diffraction, N2 adsorption/desorption measurements, FT-IR, NMR and elemental analysis to confirm the ordered mesoporous structure and the functionalization of the imidazole groups and employed as an adsorbent of Cr(VI) from aqueous solutions at room temperature. It was showed that the imidazole group can be introduced into the mesoporous channel by the postsynthesis route with high content under controlled reaction conditions. The imidazole-functionalized material exhibits high adsorption capacity of 113 mg/g for Cr(VI) and fast adsorption rate of less than 1 h in aqueous solutions. Equilibrium data were well fitted to the Langmuir adsorption isotherms.