Effect of the surface properties of resorcinol-formaldehyde resin/carbon nanocomposites and their carbonization products on the solid-phase extraction of explosives

Two polymer-nanocarbon composites, containing carbon nanotubes or exfoliated graphite, were prepared using resorcinol-formaldehyde resin. By carbonization of the composites, two additional carbon-based nanomaterials were obtained. The resulting materials were investigated with respect to their textural and morphological characteristics. The prepared composites were employed as sorbents for the separation of explosives (nitramines, nitrate esters and nitroaromatics) from aqueous samples by solid-phase extraction (SPE). The SPE results, i.e., the adsorption and desorption rates, are separately discussed. Both polymeric and carbonized composites (with nanotubes as a filler) gave high recovery rates, which reached 90%, and proved to be very effective for the extraction of explosives. The observed differences in the SPE performance of the carbonized composites were explained in terms of their porous structure, which depended on the route followed in the carbonization process. It was suggested that this process was predominantly influenced by the properties of the nanofillers employed, e.g., their high thermal conductivity, tendency to agglomerate and interactions with resin components.