(50b) Synthetic Organic Contaminant Uptake by Carbon Nanotubes

Carbon nanotubes (CNTs) hold promise to offer several potential advantages over the existing state of the art adsorbents, activated carbons and carbon fibers. To exploit this promise, purification to remove amorphous carbon and metals is often done. In addition, surface treatment such as oxidation to etch nanotube surfaces, to remove endcaps and expose inner surface area, or to add hydrophilic functional groups to enhance dispersion in aqueous solution, is also done. The effects of such treatments will be assessed in terms of their effects of organic contaminant uptake. We hypothesize that pi-pi interactions may be important in the sorption of aromatic organics, and we test this by comparing a suite of solutes have different numbers of aromatic rings, pi-bonds, and functional groups that withdraw or donate electron density. We present a side-by-side comparison with existing adsorbents, especially activated carbon, to provide a rational basis for selecting and preparing CNTs, and to evaluate whether CNTs deserve further consideration for water treatment. Of particular interest in this regard is whether competition form natural organic matter is mitigated during uptake by CNTs as compared to porous activated carbons.