期刊
WATER RESEARCH
卷 47, 期 12, 页码 4169-4178出版社
PERGAMON-ELSEVIER SCIENCE LTD
DOI: 10.1016/j.watres.2012.11.058
关键词
Fulvic acid; Antibacterial activity; Membrane permeability; Escherichia coli; Electrostatic repulsion
资金
- Natural Science Foundation of China [41073067, 41120134004]
- Shandong Excellent Young Scientist Program [BS2010HZ023]
- USDA Hatch program [MAS 00978]
This work investigated the toxicity of CuO nanoparticles (NPs) to Escherichia coli in the presence of dissolved organic matter (Dom). CuO NPs (2, 6 and 10 mg/L) exhibited high bacteria toxicity in distilled water prepared medium, with a 2 h median inhibitory concentration of 10 mg/L. The toxicity was significantly reduced by the presence of fulvic acid (FA, 5 and 40 mg/L) which is an important fraction of DOM. Bacteria membranes were highly damaged by CuO NPs, but FA mitigated this damage. Disruption of the bacteria wall and membrane was directly observed using transmission/scanning electron microscopy. Moreover, CuO NPs significantly caused the leakage of K+ ions from bacteria cells to extracellular medium, while this leakage was reduced by FA. The reduced toxicity was due to enhanced electrostatic repulsion and surface coating by FA, therefore, the physical contact between CuO NPs and bacteria membrane was hindered. These findings indicate that DOM is of importance for antibacterial activity of NPs, and more attention should be paid to the effect of DOM when assessing the environmental risk of NPs. (c) 2013 Elsevier Ltd. All rights reserved.
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