| 钟来元,沐杨昌,杨杰文.不同尺寸纳米针铁矿表面性质及其对Cr(Ⅵ)吸附量的比较[J].农业环境科学学报,2015,34(11):2120-2125. |
| 不同尺寸纳米针铁矿表面性质及其对Cr(Ⅵ)吸附量的比较 |
| Surface Properties and Cr(Ⅵ) Adsorption of Nano-goethite of Different Sizes |
| 投稿时间：2015-05-24 |
| DOI：10.11654/jaes.2015.11.012 |
| 中文关键词: 纳米针铁矿 吸附 六价铬 |
| 英文关键词: nano-geothite adsorption hexavalent chromium |
| 基金项目:国家自然科学基金面上项目(41371316);广东海洋大学大学生创新创业训练计划项目(1056613030) |
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| 中文摘要: |
| 为增进对纳米矿物在控制污染物环境行为方面的认识,通过控制Fe(Ⅲ)/OH-摩尔浓度比、老化温度,合成了尺寸大小依次为10.1、24.5、36.4 nm的针铁矿,利用XRD、HRTEM、ζ-电位和ATR-FTIR等表面分析技术研究了它们晶体结构和表面性质的差异,并比较了它们对Cr(Ⅵ)吸附量的大小.XRD分析发现10.1 nm针铁矿结晶度较低,某些晶面发育不完整.在结晶过程中,所有样品均出现某些相互平行晶面彼此粘连的晶筹现象.针铁矿体相羟基(υOH)伸缩振动、(001)晶面上羟基(δOH)面内和面外弯曲、Fe-O对称伸缩振动频率分别在3140、892、795、630 cm-1左右.10.1 nm样品表面ζ-电位和等电点(PZC)均比其他2个样品的高,说明其表面正电荷数量最多,并表现为对Cr(Ⅵ)吸附量最大.针铁矿吸附Cr(Ⅵ)后,表面ζ-电位显著降低.同时,表面吸附态Cr(Ⅵ)红外振动频率与溶液离子态有明显不同,反映针铁矿对Cr(Ⅵ)吸附方式以专性吸附为主. |
| 英文摘要: |
| 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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