(21d) Adsorption of Bacillus Subtilus on Carbon Nanotubes and Other Porous Media

Adsorption equilibrium, kinetics and column breakthrough of bacillus subtilus, a non-pathogenic surrogate for bacillus anthracis on a single-wall carbon nanotube sample were investigated to explore the feasibility of using this porous media for pathogenic molecules concentration, detection and removal from contaminated water source. The Henry constant of bacillus subtilus spores on CNT, estimated from the adsorption equilibrium data, is about 300 L/g, which is significantly higher than that of a commercial activated carbon (15 L/g) and NanoCeram®, an alumina-based porous media (2.5 L/g). The average diffusivity of bacillus subtilus spores in carbon nanotubes of 1.3x10^-9 cm²/s was obtained by fitting the adsorption kinetics data with a pore diffusion model. Nitrogen adsorption at 77°K was used to determine the pore textural properties of the adsorbents; and SEM was employed to study the morphology and particle size of the bacillus subtilus spores and the adsorbents before and after adsorption of the bacteria. The extraordinary adsorption capacity of bacillus subtilus on carbon nanotube is probably due to the unique surface chemistry of carbon nanotubes and the mesopore structures forming by the nanotubes.