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| Effects of Environmental Factors on Stability of Two Metal Oxide Nanoparticles in Aqueous Medium |
| Received:July 18, 2014 |
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| KeyWord:Nano-CeO2;Nano-TiO2;stability;humic acid;ionic strength;pH;XDLVO |
| Author Name | Affiliation | E-mail | | LÜ Xue-yan | Department of Hydrosciences, Key Laboratory of Surficial Geochemistry, Ministry of Education, Nanjing University, Nanjing 210023, China | | | SUN Yuan-yuan | Department of Hydrosciences, Key Laboratory of Surficial Geochemistry, Ministry of Education, Nanjing University, Nanjing 210023, China | sunyy@nju.edu.cn | | SHI Xiao-qing | Department of Hydrosciences, Key Laboratory of Surficial Geochemistry, Ministry of Education, Nanjing University, Nanjing 210023, China | | | XU Hong-xia | Department of Hydrosciences, Key Laboratory of Surficial Geochemistry, Ministry of Education, Nanjing University, Nanjing 210023, China | | | WU Ji-chun | Department of Hydrosciences, Key Laboratory of Surficial Geochemistry, Ministry of Education, Nanjing University, Nanjing 210023, China | jcwu@nju.deu.cn |
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| Abstract: |
| The ecological and environmental effects of nanoparticles in the aqueous medium are dependent on their stability. However, the stability is greatly influenced by environmental factors. This work examined the effects of humic acid(HA) concentration, ionic strength(IS)and pH on the stability of Nano-CeO2 and Nano-TiO2 in aqueous suspension. The presence of HA significantly promoted the stability of nanoparticles(NPs) in the suspension(0~5 mg·L-1), due to increased steric effect and electrostatic repulsion between NPs by HA coated on the NPs. Although increasing IS(1~50 mmol·L-1 NaCl) could decrease NP stability in the suspension, HA(5 mg·L-1) could weaken this effect by introducing greater steric repulsion. Similarly, the presence of 5 mg·L-1 HA decreased the effects of pH increasing from 6.01 to 10.02 on NP stability. In addition, all the experimental data matched well with the predictions based on extended Derjaguin-Landau-Verwey-Overbeek(XDLVO) theory. Our findings could gain insights into the behavior of Nano-CeO2 and Nano-TiO2 in aqueous medium, and provide theoretical basis for environmental risk assessment of Nano-CeO2 and Nano-TiO2. |
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