Department of Environmental Science, College of Environmental Science and Engineering, Tongji University, State Key Laboratory of Pollution Control and Resources Reuse, Shanghai Institute of Pollution Control and Ecological Security, Shanghai 200092, PR China.
Department of Environmental Science, College of Environmental Science and Engineering, Tongji University, State Key Laboratory of Pollution Control and Resources Reuse, Shanghai Institute of Pollution Control and Ecological Security, Shanghai 200092, PR China.
Water Res. 2022 Aug 1;221:118773. doi: 10.1016/j.watres.2022.118773. Epub 2022 Jun 17.
The transport of microplastics (MP) or nanoplastics (NP) in porous media has been widely reported. However, their mutual interaction and effect on cotransport remain unclear. Here, we investigated the colloidal interaction between NP (50 nm), submicroplastics (SP, 300 nm), and MP (1000 nm) in seawater and their cotransport in saturated natural sea sands. In the single-component suspension, the recovered mass percentage (M) of colloids was as follows: MP (47.81%) > NP (24.18%) > SP (21.66%). SP and MP remained monodispersed. MP had the highest mobility due to the strongest electrostatic repulsion with sand surface, whereas NP formed homoaggregates and was characterized by ripening phenomena. In the SP-MP mixture, SP and MP kept independent mobility without mutual effect. In the NP-SP-MP mixture, the M of MP was reduced by 10% because unstable NP induced MP to form heteroaggregates with SP, which could not pass through the pores. In addition, NP attached to the sand surface could form additional retention sites to retain MP. By contrast, SP showed a 13% increase in M because MP became an indirect carrier of SP through the bridging of NP. Overall, this study demonstrates the dominant role of unstable NP in the cotransport of NP-SP-MP in the marine sedimentary environment.
微塑料（MP）或纳米塑料（NP）在多孔介质中的迁移已被广泛报道。然而，它们在共运移过程中的相互作用和影响仍不清楚。在这里，我们研究了海水NP（50nm）、亚微塑料（SP，300nm）和 MP（1000nm）之间的胶体相互作用及其在饱和天然海砂中的共运移。在单一成分悬浮液中，胶体的回收质量百分比（M）如下：MP（47.81%）>NP（24.18%）>SP（21.66%）。SP 和 MP 保持单分散。由于与砂表面的静电排斥最强，MP 具有最高的迁移率，而 NP 形成同聚体，并表现出成熟现象。在 SP-MP 混合物中，SP 和 MP 保持独立的迁移率而没有相互作用。在 NP-SP-MP 混合物中，MP 的 M 减少了 10%，因为不稳定的 NP 诱导 MP 与 SP 形成异聚体，无法通过孔隙。此外，附着在砂表面的 NP 可以形成额外的滞留点来保留 MP。相比之下，SP 的 M 增加了 13%，因为 MP 通过 NP 的桥接成为 SP 的间接载体。总的来说，本研究表明，在海洋沉积环境中，不稳定的 NP 在 NP-SP-MP 的共运移中起主导作用。
