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| Surface Properties and Cr(Ⅵ) Adsorption of Nano-goethite of Different Sizes |
| Received:May 24, 2015 |
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| KeyWord:nano-geothite;adsorption;hexavalent chromium |
| Author Name | Affiliation | E-mail | | ZHONG Lai-yuan | Department of Resources and Environmental Sciences, College of Agriculture, Guangdong Ocean University, Zhanjiang 524088, China | | | MU Yang-chang | Department of Resources and Environmental Sciences, College of Agriculture, Guangdong Ocean University, Zhanjiang 524088, China | | | YANG Jie-wen | Department of Resources and Environmental Sciences, College of Agriculture, Guangdong Ocean University, Zhanjiang 524088, China | jw_yang@126.com |
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| Abstract: |
| Nanoparticles have huge surface area and surface activity and thus great adsorption capacity. However, different sized nanoparicles have showed various adsorption. In this study, the surface properties of three nano-goethite samples with different sizes were characteristized by use of XRD, HRTEM, ζ-potential and ATR-FTIR. Their adsorption capacity for Cr(Ⅵ) was also compared. The 10.1 nm goethite had the lowest crystallinity with some poorly developed crystal faces. Multi-domain was observed in all samples, possibly indicating the coherent adherence of(101) faces. The IR bands of bulk hydroxyl stretch and symmetric Fe-O stretch were found around 3140 and 630 cm-1, respectively. Moreover, two intense bands due to surface hydroxyl vibrating in and out(001) plane were observed around 890 and 790 cm-1. The 10.1 nm goethite sample had the largest capacity for Cr(Ⅵ) adsorption because it had the highest point of zero charge(PZC) and thus the most positive charges among three samples. Adsorption of Cr(Ⅵ) by nano-goethite was ascribed to the formation of inner-sphere complexes, as evidenced by decrease in surface ζ-potential as well as the significant difference in IR bands between the adsorbed and aqueous Cr(Ⅵ) species. These results would advance our understanding of nano-particles in controlling environmental behaviors of pollutants. |
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