Different N-containing functional groups modified mesoporous adsorbents for Cr(VI) sequestration: Synthesis, characterization and comparison

Ordered mesoporous SBA-15 has been functionalized by aminopropyl, imidazole and triazole groups by one or two-step post-grafting route and investigated as adsorbents of hexavalent chromium in aqueous solutions. XRD, N2 adsorption–desorption measurements, FT-IR, solid state NMR and element analysis techniques have been employed to prove the ordered mesoporous structures of the functionalized SBA-15 and the successful immobilization of the organic functional moieties on SBA-15. The Cr(VI) adsorption behavior on the resultant adsorbents were examined by a batchwise method. The results show that all adsorbents exhibit the fast adsorption rate and the excellent adsorption capacity. Electrostatic interaction between the adsorbents and adsorbate plays an important role in the adsorption process. Equilibrium data were well fitted to the Langmuir and Freundlich adsorption models.