The influence of proteins on the transport and deposition behaviors of microplastics (MPs) in quartz sand was examined at both low (5 mM) and high ionic strength (25 mM) in NaCl solutions at pH 6. Carboxylate- and amine-modified polystyrene latex microspheres with size of 200 nm were employed as negatively (CMPs) and positively surface charged MPs (AMPs), respectively, while bovine serum albumin (BSA) and bovine trypsin were utilized as representative negatively and positively charged proteins, respectively. The results showed that for two examined protein concentrations (both 1 and 10 mg/L TOC) under both ionic strength conditions, the presence of BSA increased the transport of both CMPs and AMPs, while the presence of trypsin decreased the transport of CMPs yet increased the transport of AMPs in porous media. The mechanisms driving to the changed transport of MPs induced by two types of proteins were found to be different. Particularly, steric interaction induced by BSA corona adsorbed onto CMPs surface as well as the repel effects resulted from BSA suspending in solutions were found to contribute to the enhanced CMPs transport with BSA copresent in suspensions. The increased sizes and the decreased electrostatic repulsion of CMPs due to the adsorption of trypsin onto CMPs, together with the addition of extra deposition sites due to the adsorption of trypsin onto quartz sand drove to the decreased CMPs transport with trypsin copresent in suspensions. The increased electrostatic repulsion due to the adsorption of BSA onto AMPs surfaces caused the enhanced AMPs transport with BSA in solutions. While, the decreased electrostatic attraction of AMPs due to the adsorption of trypsin onto AMPs, as well as the competition of deposition sites due to the adsorption of trypsin onto quartz sand contributed to the increased AMPs transport with trypsin copresent in suspensions. The results showed that the presence of different types of proteins would induce different transport behaviors of microplastics with different surface charge in porous media. Since proteins are widely present in aquatic systems, to more accurately predict the fate and transport of MPs in natural environments, the effects and mechanisms of proteins on the transport of MPs should be considered.

在pH值为6的NaCl溶液中，在低（5 mM）和高离子强度（25 mM）下，都检查了蛋白质对微塑料（MPs）在石英砂中的迁移和沉积行为的影响。羧酸盐和胺改性的聚苯乙烯胶乳将大小为200 nm的微球分别用作负电荷（CMP）和带正电荷的表面MP（AMP），而将牛血清白蛋白（BSA）和牛胰蛋白酶分别用作代表性的负电荷和正电荷蛋白质。结果表明，在两种离子强度条件下，对于两种检测的蛋白质浓度（TOC分别为1和10 mg / L），BSA的存在均会增加CMP和AMP的转运，而胰蛋白酶的存在会降低CMP的转运但仍增加AMP在多孔介质中的运输。发现驱动由两种蛋白质诱导的MP改变运输的机制是不同的。特别地，发现由BSA电晕吸附到CMPs表面上引起的空间相互作用，以及由BSA悬浮在溶液中引起的排斥作用，有助于与悬浮液中共存的BSA一起增强CMPs的运输。由于胰蛋白酶吸附在CMP上而导致CMP尺寸的增加和静电排斥力的降低，以及由于胰蛋白酶吸附在石英砂上而增加了额外的沉积位点，这导致CMP的迁移减少，胰蛋白酶在悬浮液中共存。由于BSA吸附在AMPs表面上而增加的静电排斥力导致溶液中AMPs与BSA的运输增强。而，胰蛋白酶吸附到AMPs上引起的AMPs静电吸引降低，以及胰蛋白酶吸附到石英沙上引起的沉积位竞争，都导致了胰蛋白酶在悬浮液中共存时AMPs的转运增加。结果表明，不同类型蛋白质的存在会诱导具有不同表面电荷的微塑料在多孔介质中的不同迁移行为。由于蛋白质广泛存在于水生系统中，为了更准确地预测自然环境中MP的命运和转运，应考虑蛋白质对MP转运的影响和机理。胰蛋白酶吸附到石英砂上引起的沉积位竞争以及与胰蛋白酶共同存在于悬浮液中的AMPs转运增加。结果表明，不同类型蛋白质的存在会诱导具有不同表面电荷的微塑料在多孔介质中的不同迁移行为。由于蛋白质广泛存在于水生系统中，为了更准确地预测自然环境中MP的命运和运输，应考虑蛋白质对MP运输的影响和机理。胰蛋白酶吸附到石英砂上引起的沉积位竞争以及与胰蛋白酶共同存在于悬浮液中的AMPs转运增加。结果表明，不同类型蛋白质的存在会诱导具有不同表面电荷的微塑料在多孔介质中的不同迁移行为。由于蛋白质广泛存在于水生系统中，为了更准确地预测自然环境中MP的命运和转运，应考虑蛋白质对MP转运的影响和机理。