Aggregation and ecotoxicity of CeO₂ nanoparticles in synthetic and natural waters with variable pH, organic matter concentration and ionic strength
2011
Van Hoecke, Karen | De Schamphelaere, Karel A.C. | Van der Meeren, Paul | Smagghe, Guy | Janssen, Colin R.
The influence of pH (6.0–9.0), natural organic matter (NOM) (0–10 mg C/L) and ionic strength (IS) (1.7–40 mM) on 14 nm CeO₂ NP aggregation and ecotoxicity towards the alga Pseudokirchneriella subcapitata was assessed following a central composite design. Mean NP aggregate sizes ranged between 200 and 10000 nm. Increasing pH and IS enhanced aggregation, while increasing NOM decreased mean aggregate sizes. The 48 h-EᵣC20s ranged between 4.7 and 395.8 mg CeO₂/L. An equation for predicting the 48 h-EᵣC20 (48 h-EᵣC20 = −1626.4 × (pH) + 109.45 × (pH)² + 116.49 × ([NOM]) − 14.317 × (pH) × ([NOM]) + 6007.2) was developed. In a validation study with natural waters the predicted 48 h-EᵣC20 was a factor 1.08–2.57 lower compared to the experimental values.
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