This study examines the effect of graphene oxide (GO) nanoparticles (NPs) on the transport (individual species) and cotransport (simultaneous transport) of three biocolloids (Escherichia (E.) coli, Enterococcus (E.) faecalis and Staphylococcus (S.) aureus) in water saturated porous media. Flowthrough experiments were performed in 30-cm long laboratory columns packed with quartz sand. All of the experiments were conducted at room temperature (22 °C), pH = 7, and ionic strength Is = 2 mM. The results from the cotransport experiments indicated that the mass recovery values for all biocolloids, calculated based on total biocolloid concentration in the effluent, were reduced in the presence of GO NPs. The strains E. coli and E. faecalis were shown to be more vulnerable to GO NPs than S. aureus. Temporal moments of the breakthrough concentrations suggested that the presence of GO NPs significantly influenced the fate and transport of the three biocolloids. Extended DLVO theory was used to quantify the various interaction energy profiles, based on electrokinetic and hydrodynamic measurements.
Keywords: Cotransport in porous media; Enterococcus faecalis; Escherichia coli; Graphene oxide; Quartz sand; Staphylococcus aureus.
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