Influence of Media Size and Flow Rate on the Transport of Silver Nanoparticles in Saturated Porous Media: Laboratory Experiments and Modeling.

摘要

Silver nanoparticles (AgNPs) are widely produced and used. Because of their potential toxicity and the possibility of their release into the environment, it is important to understand the factors involved in their transport; particularly how they may move in groundwater, which is a potential pathway to human and environmental receptors. By passing a solution of 15 mg/L AgNPs with an average size of 17 nm through sand-filled glass columns, this study looks at the physical effects of flow rate and media size on transport. Three different sand sizes. (<0.074, 0.21-0.297, and 0.4-2.0mm) were used, as well as two different flow rates (1 and 4 mL min-1). Results showed that flow rate had little effect on the transport of AgNPs. As had been found in previous studies, transport through fine sand (<0.074 mm) was inhibited, and no AgNPs were observed in the column effluent. In contrast to other studies and conventional filtration theory, however, it was observed that more AgNPs were captured in the coarse sand (0.4-2.0 mm) than the medium sand (0.21-0.297 mm). This deviation from conventional filtration theory was attributed to the more heterogeneous size distribution of the coarse sand compared to the medium sand.