As emerging contaminants of global concern, nanoplastics are significantly potential carriers of hydrophobic organic compounds in aquatic and soil environment. However, little is known about the interactions between the transports of nanoplastics and organic contaminants in porous media. In this study, the cotransport of naphthalene with polystyrene nanoplastics (PSNP) in saturated sand columns as influenced by the PSNP/naphthalene ratio and ionic strength (IS) was investigated. The presence of PSNP dramatically enhanced the mobility of naphthalene at low IS (0.5 mM), but such effect was prohibited at high IS (5 mM and 50 mM). The mobility of PSNP in the sand column was higher when it was solely exist in the pore-water than that when in the presence of naphthalene, because of the charge-shielding effect. This work showed that the coexistence of PSNP and naphthalene would influence the mobility of each other in the saturated porous media, which highly related to their concentration ratio and IS levels.
Keywords: Ionic strength; Nanoplastics; Naphthalene; Porous media; Transport.
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