Adsorption of Bacillus subtilis on single-walled carbon nanotube aggregates, activated carbon and NanoCeram™

Adsorption equilibrium and kinetics of Bacillus subtilis spores on single-walled carbon nanotube aggregates were investigated to explore the possibility of using single-walled carbon nanotubes for concentration, detection and removal of pathogens from contaminated water sources. Batch adsorption experiments were conducted to determine adsorption kinetics and adsorption equilibrium of B. subtilis spores on single-walled carbon nanotube aggregates, activated carbon and NanoCeram™. The adsorption kinetics data were analyzed with both the Lagergren pseudo first order and a pseudo second order models. The adsorption equilibrium data on three porous media were quantified by the Henry's law constant. It was observed that both the Lagergren first order rate model and the pseudo second order model correlate the adsorption kinetic data well although the calculated adsorption rate constants vary with adsorbate concentrations. The Henry's law adsorption equilibrium constant of B. subtilis spores on single-walled carbon nanotube aggregates is about 27-37 times higher than those on activated carbon and NanoCeram™. The high adsorption affinity of carbon nanotubes towards the B. subtilis spores is due to the mesoporous structure and unique surface properties of carbon nanotubes. These results suggest that single-walled carbon nanotube aggregates are good candidates as biosensors and adsorbent media for concentrating, detecting and removal of pathogens from contaminated water resources.