Among considerable engineered nanomaterials, CeO2 nanoparticles (NPs) are of particular interest due to their unique oxidative, optical and electrical properties. As result of rapidly grown nanotechnology industries, release of CeO2 NPs to environment has increased, posing a threat to the ecosystem and public health. In this study, different synthesis methods of CeO2 NPs were studied, and NH4OH precipitation method provided the best result. The transmission electron microscopy images demonstrated that average particle size of CeO2 NPs was 12.87 nm and in spherical shape. The particle size distributions and zeta potential of nanoparticles in water were determined using dynamic light scattering. Our synthesized CeO2 NPs were highly monodispersed, and the hydrodynamic diameter of CeO2 NPs was around 30 nm. The value of pHzpc was found equal to 2.2 ± 0.1. The X-ray diffraction analysis indicated a good crystallite of CeO2. The valence states of Ce in CeO2 NPs were 3 and 4 , which was determined by X-ray absorption near edge structure spectra. To better understand the fate and potential toxicity towards aquatic environment, aggregation and sedimentation of CeO2 NPs were investigated in different concentrations of two common electrolytes, NaCl and CaCl2 solutions. CeO2 NPs kept stable in NaCl solution within 3 days. In contrast, CeO2 NPs quickly aggregated and exceeded micrometres in CaCl2 solution. Moreover, CeO2 NPs would quickly aggregate and settle down in cell culture medium (FBS free). On the other hand, CeO2 NPs were stable in medium containing FBS within 2 days. The cytotoxicity of CeO2 NPs was evaluated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenylte-trazolium bromide (MTT) assay. The result of MTT assays showed that CeO2 NPs did not have a significant toxic effect on neuro2A cells (N2A cells). These findings facilitated understanding and prediction of the behaviour and fate of CeO2 NPs in the environment.

Stability and cytotoxicity of synthesized CeO2 nanoparticles in water

253rd National Meeting (2017)

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