Batch adsorption studies to determine adsorption kinetics of Escherichia coli (E.coli) K12 and Staphylococcus aureus (S.aureus) SH 1000 bacterial cells on single-walled carbon nanotube aggregates were performed at two different initial concentrations. The diffusivity of E. coli cells in single-walled carbon nanotube aggregates obtained was 6.54 × 10−9 and 8.98 × 10–9 cm2/s, whereas that of S. aureus was between 1.00 × 10–7 and 1.66 × 10–7 cm2/s respectively. In addition to batch adsorption studies, electron microscopy studies were also conducted. The results suggest that diffusion kinetics of bacterial cells is concentration dependent as well as bacteria dependent. Diffusivity of S. aureus is two orders of magnitude greater than E. coli cells. This proves to be beneficial from an adsorption perspective where it is desired to filter microorganisms (water pretreatment and wastewater post treatment) and from nanotube biosensor perspective where it is desired to simultaneously capture and detect biothreat agents in a shorter span of time.