期刊
WATER RESEARCH
卷 46, 期 14, 页码 4477-4487出版社
PERGAMON-ELSEVIER SCIENCE LTD
DOI: 10.1016/j.watres.2012.05.035
关键词
Nanomaterial; Natural organic matter; Alga; Toxicity; Sorption
资金
- National Basic Research Program of China [2008CB418204]
- National Natural Science Foundation of China [21077089]
- Zhejiang Provincial Natural Science Foundation of China [LR12807001]
- Program for New Century Excellent Talents in University [NCET-10-0731]
- Zhejiang Provincial Innovative Research Team of Water Treatment Functional Materials and their Application
NOM is likely to coat TiO2 nanoparticles (nano-TiO2) discharged into the aquatic environment and influence the nanotoxicity to aquatic organisms, which however has not been well investigated. This study explored the influence of nanoparticle surface-bound humic acid (HA, as a model NOM) as well as dissolved HA on the toxicity of nano-TiO2 to Chlorella sp., with a specific focus on adhesion of the nanoparticles to the algae. Results showed that nano-TiO2 and the dissolved HA could inhibit the algal growth with an IC50 of 4.9 and 8.4 mg L-1, respectively, while both dissolved and nanoparticle surface-bound HA could significantly alleviate the algal toxicity of nano-TiO2. IC50 of nano-TiO2 increased to 18 mg L-1 in the presence of 5 mg L-1 of the dissolved HA and to 48 mg L-1 as the result of surface-saturation by HA. Co-precipitation experiment and transmission electron microscopy observation revealed that both dissolved and nanoparticle surface-bound HA prevented the adhesion of nano-TiO2 to the algal cells due to the increased electrosteric repulsion. The generation of intracellular reactive oxygen species (ROS) was significantly limited by the dissolved and nanoparticle surface-bound HA. The prevention of adhesion and inhibition of ROS generation could account for the HA-mitigated nanotoxicity. (C) 2012 Elsevier Ltd. All rights reserved.
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