Influence of nanoparticle doping on the colloidal stability and toxicity of copper oxide nanoparticles in synthetic and natural waters

• Published in: Water research (Oxford) Vol. 132; pp. 12 - 22
• Main Authors: Adeleye, Adeyemi S., Pokhrel, Suman, Mädler, Lutz, Keller, Arturo A.
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.04.2018
• Subjects: Copper oxide nanoparticle; Environmental fate; Natural waters; Toxicity; Transformation; Environmental fate; Transformation; Copper oxide nanoparticle; Toxicity; Natural waters
• ISSN: 0043-1354; 1879-2448
• DOI: 10.1016/j.watres.2017.12.069

Engineered nanoparticles (NPs) are often doped with other elements to improve their functionality and, at times, physical and/or chemical stability. However, the effect of doping on the environmental implications of NPs is not well-understood. We investigated the colloidal stability and effects of CuO NPs doped with Fe (0–10%). Colloidal stability of the Fe-doped CuO NPs in aqueous media, as determined by critical coagulation concentrations of NaCl, decreased with increased Fe-doping. However, decrease in the overall particle density led to slower sedimentation of Fe-doped CuO NPs than would have been predicted from their aggregation behavior. Fe-doping significantly affected CuO dissolution (p < .001), promoting Cu leaching out from the doped NPs due to increased reactivity at neutral pH and increased surface area with Fe-doping. Fe-doping did not increase the toxicity of CuO to a marine phytoplankton, Isochrysis galbana, despite promoting ionic Cu release. Total suspended Cu was dominated by dissolved Cu complexes in seawater and particulate Cu in freshwater. Based on the abundance of different size fractions analyzed in freshwater, the particles detected in water suspension were mostly (≥50%) larger than 200 nm in diameter. However, these large-sized particles are mainly composed of aggregated nanosized particles held together by van der Waals attraction. [Display omitted] •Zeta potential shifted towards that of the dopant with increased Fe-doping.•Fe-doping decreased the colloidal stability of CuO nanoparticles.•Cu leaching from CuO nanoparticles in natural waters increased with Fe-doping.•Fe-CuO nanoparticle was not toxic to marine algae up to 10 mg/L.