期刊
CHEMOSPHERE
卷 245, 期 -, 页码 -出版社
PERGAMON-ELSEVIER SCIENCE LTD
DOI: 10.1016/j.chemosphere.2019.125612
关键词
Copper oxide nanoparticles; Dissolution; Dissolved humic acid; Cu complexation; Particle dispersion; Negative charge-assisted H-Bond
资金
- National Natural Science Foundation of China, China [41703111, 41967039, 41701571, 41703121]
- Talent cultivation project at Kunming University of Science and Technology, China [KKSY201622012]
- European Union's Horizon 2020 research and innovation programme, European Research Council [642007]
Humic substances are the dominant dissolved organic matter fraction in the aqueous phase of environmental media. They would inevitably react with chemicals released into the environment. The influence of dissolved humic acid (DHA) on the dissolution and dispersion of copper oxide nanoparticles (CuO NPs, 50 nm, 49.57 mg L-1) was therefore investigated in the present study. In addition to dispersing CuO NPs and reducing the size of the aggregates, the amount of released Cu from CuO NPs was found to increase over time with increasing concentrations of DHA, 96% of which was present as organic complexes after 72 h. At DHA concentrations exceeding 16.09 mg C L-1, the complexation coefficients of DHA with Cu and the adsorptivity of CuO NPs to DHA were both reduced due to increased homo-conjugation of DHA as promoted by negative charge-assisted H-bond. Although the adsorption capacity of DHA kept increasing up to 57.07 mg C L-1, the hydrodynamic diameter and zeta-potential were similar and the percentages of total released Cu continued to increase linearly to 4.92% at higher levels of DHA (30.13 -57.07 mg C L-1). Thereupon, DHA promoted the dissolution of CuO NPs in a concentration-dependent fashion. The driving force was complexation of Cu by DHA, rather than the balancing between the exposed and the covered surface area of the CuO NPs due to DHA adsorption. Our findings facilitate understanding the underlying mechanisms on how DHA impacts the CuO NPs environmental behavior (or fate) as well as on their kinetics. (C) 2019 Elsevier Ltd. All rights reserved.
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