Capturing nitrosamines in tobacco-extract solution by hydrophobic mesoporous silica

Adsorption of tobacco-specific nitrosamines (TSNA) by the functionalized MCM-48 mesoporous silica in tobacco-extract solution was studied using batch experiments, in order to explore the new strategy enhancing the efficiency of molecular sieve in the solution with complex composition. The techniques of XRD, N-2 adsorption-desorption at 77 K, Si-29 MAS NMR, Al-27 MAS NMR and TG-DSC together with FTIR were used to inspect the mesoporous adsorbents. The hydrophobic character of adsorbent is crucial for the adsorption of TSNA in aqueous solution, and the organic 3-chloropropyltriethoxysilane (CPTES) was employed to functionalize the ordered porous silica through direct co-condensation and post-synthesis grafting methods. Besides, aluminum is also incorporated into the framework of MCM-48 to enhance the adsorption capability of nitrosamines. As the result, about 70% of TSNA can be removed by the chloropropyl-modified Al-containing mesoporous silica, obviously exceeded that by activated carbon, offering the new efficient adsorbents for environment protection. (C) 2009 Elsevier B.V. All rights reserved.