Role of water chemistry on stability, aggregation, and dissolution of
uncoated and carbon-coated copper nanoparticles
Ayenachew Tegenawa
, George A. Soriala,∗
, Endalkachew Sahle-Demessieb
, Changseok Hanc a Environmental Engineering Program, Department of Chemical and Environmental Engineering, College of Engineering and Applied Science, University of Cincinnati, 701
Engineering Research Center, 2901 Woodside Drive P.O. Box 210012, Cincinnati, OH, 45221-0012, United States
b U.S. Environmental Protection Agency, Office of Research and Development, Center for Environmental Solution and Emergency Response, 26 W. Martin Luther Drive,
Cincinnati, OH, 45268, United States
c Department of Environmental Engineering, College of Engineering, INHA University, 100 Inharo, Nam-gu Incheon, 22212, South Korea
ARTICLE INFO
Keywords:
Aggregation
Cu-NPs fate
Ecological risks
Risk analysis
Water chemistry
ABSTRACT
Intentional or accidental release of copper nanoparticles (Cu-NPs) from consumer products during manufacturing, use, and end-of-life management could pose health and ecological risks. This paper presents a detailed
study on the role of water chemistry on the fate of uncoated and carbon-coated Cu-NPs dispersed in aqueous
cetyltrimethylammonium bromide (CTAB) surfactant in the presence and absence of humic acids (HAs). A range
of water chemistry and HAs had minimum impact on hydrodynamic diameter and zeta-potential values of uncoated and carbon-coated Cu-NPs. The water pH significantly (p < 0.001) affected the aggregation of uncoated
Cu-NPs unlike that of carbon-coated Cu-NPs; however, the presence of HAs increased the stability of uncoated
Cu-NPs. Although CTAB is considered as an efficient dispersant to stabilize Cu-NPs, the effect descended with
time for uncoated Cu-NPs. The dissolution of Cu over time decreased with increasing pH for both uncoated
(0.5–50% weight) and carbon-coated (0.5–40% weight) Cu-NPs. However, carbon-coated Cu-NPs exhibited
significant dissolution (p < 0.001) at neutral pH than uncoated Cu-NPs may be due to the additional carbon it
acquired during coating. Increasing HAs concentration from 0 to 15 mg L−1 at pH 5.5 inhibited aggregations but
enhanced dissolution of the uncoated and carbon-coated Cu-NPs. These findings inform risk analysis of Cu-NPs
including how Cu-NPs fate, mobility and bioavailability are modulated by particles coating and dispersant, HAs
presence, water chemistry and exposure time in dispersion media.