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

WATER RESEARCH

卷:186

Article

Li, Xing¹  He, Erkai²  Xia, Bing³  Van Gestel, Cornelis A. M.⁴  Peijnenburg, Willie J. G. M.^5,6  Cao, Xinde¹  Qiu, Hao¹ 

[1] Shanghai Jiao Tong Univ, Sch Environm Sci & Engn, Shanghai 200240, Peoples R China

[2] East China Normal Univ, Sch Geog Sci, Shanghai 200241, Peoples R China

[3] Anhui Acad Environm Sci Res, Hefei 230022, Peoples R China

[4] Vrije Univ, Dept Ecol Sci, Fac Sci, NL-1081 HV Amsterdam, Netherlands

[5] Leiden Univ, Inst Environm Sci, NL-2333 CC Leiden, Netherlands

[6] Ctr Safety Subst & Prod, Natl Inst Publ Hlth & Environm, NL-3720 BA Bilthoven, Netherlands

关键词: Engineered nanoparticles;    Surface functional groups;    Hydrochemical condition;    Stability;   

DOI  :  10.1016/j.watres.2020.116324

来源: Elsevier

【 摘 要 】

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. (c) 2020 Elsevier Ltd. All rights reserved.

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