Macroporous silica for concentration of nitroenergetic targets.

Hierarchical organosilicate sorbents were synthesized which possess structure on two length scales: macropores of approximately 1microm lined by mesopores (35-45A). The incorporation of macropores provides enhanced flow-through characteristics over purely mesoporous materials, thereby reducing back pressure when used in column formats. Materials of this type with varied surface groups were applied to the adsorption of 2,4,6-trinitrotoluene (TNT) and 1,3,5-trinitro-1,3,5-triazacyclohexane (RDX) in both batch and column formats. The results presented here demonstrate the potential of these materials for application as solid phase extraction materials for the pre-concentration of nitroenergetic targets from aqueous solutions. The structural and binding characteristics of the materials have been evaluated and preliminary data on the impact of complex matrices is provided.