“…48,49 They found that the presence of rhamnolipid (5-50 mg L −1 ) enhanced the transport of silver nanoparticles due to rhamnolipid adsorption onto the surfaces of silver nanoparticles, which effectively slowed the oxidation, as well as adsorption of rhamnolipid onto sand surfaces, which competed for silver nanoparticle attachment sites. 49 Moreover, Zhao et al found that 0.1% saponins signicantly enhanced the secondary transport of Pseudomonas migulae AN-1 cells due to the decreased hydrophobicity of bacteria and quartz sand. 50 Considering the unique chemical structure of GO (i.e., a layered nanomaterial containing graphene sheets and abundant reactive oxygen functional groups), 1 it likely interacts with biosurfactants via van der Waals interaction, hydrogen bonding, and/or hydrophobic interaction.…”