Coagulation of TiO2, CeO2 nanoparticles, and polystyrene nanoplastics in bottled mineral and surface waters. Effect of water properties, coagulant type, and dosage

Intensive use of engineered nanoparticles (NPs) and plastic materials has ineluctably resulted in their release into aquatic systems including drinking water resources. This issue has become a major environmental concern. This study, in collaboration with the SSIGE (Swiss Society of the Gaz and Water Industries) and SIG (Services Industriels de Genève) aimed to understand the behavior of nanoplastics and metal oxide NPs during coagulation process, as well as the effect of water properties such as pH, water hardness, and presence of Natural Organic Matter (NOM) on the coagulation efficiency. The effect of two conventional and operational coagulants, polyaluminum chloride (PACl) and iron chloride (FeCl3), on TiO2, CeO2 NPs and polystyrene (PS) nanoplastics was investigated. Our results demonstrate that NPs and PS nanoplastics surface charges are strongly influenced by external drivers such as pH, presence of divalent cations and NOM concentration. Internal drivers such as coagulant type and dosage are also found to play roles in promoting coagulation through different mechanisms such as surface charge neutralization, sweep coagulation and precipitation. Such results contribute to a better understanding of the different parameters affecting NPs and PS nanoplastics coagulation, to control and limit environmental and health risks associated with nanoparticles exposure and optimize drinking water production processes.

 

Link to article: https://archive-ouverte.unige.ch/unige:137074

 

8 October 2020

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