Impact of CeO2 nanoparticles on the aggregation kinetics and stability of polystyrene nanoplastics: Importance of surface functionalization and solution chemistry

Xing Li, Erkai He, Bing Xia, Cornelis A.M. Van Gestel, Willie J.G.M. Peijnenburg, Xinde Cao, Hao Qiu*

*Corresponding author for this work

    Research output: Contribution to JournalArticleAcademicpeer-review

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    Abstract

    The increasing application of plastics is accompanied by increasing concern over the stability and potential risk of nanoplastics. Heteroaggregation with metal-based nanoparticles (e.g., CeO2-NPs) is critical to the environmental mobility of nanoplastics, as they are likely to be jointly emitted to the aquatic environment. Here, time-resolved dynamic light scattering was employed to evaluate the influence of CeO2-NPs on the aggregation kinetics of differentially surface functionalized polystyrene nanoplastics (PS-NPs) in various water types. Natural organic matters and ionic strength were dominating factors influencing the heteroaggregation of PS-NPs and CeO2-NPs in surface waters. The critical coagulation concentrations of PS-NPs were dependent on their surface coatings, which decreased in the presence of CeO2-NPs due to electrostatic attraction and/or specific adsorption. Incubation of PS-NPs and CeO2-NPs under different pH confirmed the importance of electrostatic force in the aggregation of PS NPs. A relatively low humic acid (HA) concentration promoted the heteroaggregation of NH2-coated PS-NPs and CeO2-NPs because the introduction of a HA surface coating decreased the electrostatic hindrance. At high HA concentrations, the aggregation was inhibited by steric repulsion. The combined effects of high efficiency of double layer compression, bridging and complexation contributed to the high capacity of Ca2+ in destabilizing the particles. These findings demonstrate that the environmental behavior of nanoplastics is influenced by the presence of other non-plastic particles and improve our understanding of the interactions between PS-NPs and CeO2-NPs in complex and realistic aqueous environments.

    Original languageEnglish
    Article number116324
    Pages (from-to)1-12
    Number of pages12
    JournalWater Research
    Volume186
    Early online date20 Aug 2020
    DOIs
    Publication statusPublished - 1 Nov 2020

    Funding

    This study was supported by the National Natural Science Foundation of China (No. 41877500, No. 41701571, No. 41701573, and No. 41977115), Shanghai Rising-Star Program (No. 20QA1404500), the National Key R&D Program of China (No. 2018YFC1800600, No. 2018YFD0800700), Science and Technology Program of Guangzhou, China (No. 201904010116). This study was supported by the National Natural Science Foundation of China (No. 41877500 , No. 41701571 , No. 41701573 , and No. 41977115 ), Shanghai Rising-Star Program (No. 20QA1404500 ), the National Key R&D Program of China (No. 2018YFC1800600 , No. 2018YFD0800700 ), Science and Technology Program of Guangzhou , China (No. 201904010116 ).

    FundersFunder number
    National Key R&D Program of China
    National Natural Science Foundation of China41701571, 41701573, 41877500, 41977115
    Guangzhou Science and Technology Program key projects201904010116
    National Key Research and Development Program of China2018YFD0800700, 2018YFC1800600
    Shanghai Rising-Star Program20QA1404500

      Keywords

      • Engineered nanoparticles
      • Hydrochemical condition
      • Stability
      • Surface functional groups

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