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 language | English |
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Article number | 116324 |
Pages (from-to) | 1-12 |
Number of pages | 12 |
Journal | Water Research |
Volume | 186 |
Early online date | 20 Aug 2020 |
DOIs | |
Publication status | Published - 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 ).
Funders | Funder number |
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National Key R&D Program of China | |
National Natural Science Foundation of China | 41701571, 41701573, 41877500, 41977115 |
Guangzhou Science and Technology Program key projects | 201904010116 |
National Key Research and Development Program of China | 2018YFD0800700, 2018YFC1800600 |
Shanghai Rising-Star Program | 20QA1404500 |
Keywords
- Engineered nanoparticles
- Hydrochemical condition
- Stability
- Surface functional groups