【作者】 贾志君；

【导师】 元光；

【作者基本信息】 中国海洋大学 ， 海洋信息探测与处理， 2012， 博士

【摘要】 海洋中的营养盐是指与生物过程有密切关系的元素。在海洋学上,传统的营养元素术语几乎是氮、磷、硅三种元素的专有名称。营养盐对于海洋生物的生长无疑具有重要作用,但是营养盐的反常分布也会对其生长造成巨大的刺激,像2008年青岛地区的浒苔大爆发就是一起典型的因为营养盐含量异于正常值引起的海洋生物污染。因此对海洋营养盐含量进行快速检测就成为一个急需解决的课题。传统的海洋营养盐检测是采用化学显色结合光度学测量的方法,测量精度高,但是测量过程复杂、费时。本文尝试利用银/二氧化硅纳米复合材料的表面增强红外光谱(Surface-enhanced Infrared Absorption Spectroscopy, SEIRAS)和表面增强拉曼光谱(Surface-enhanced Raman Spectroscopy, SERS)技术,探索海洋营养盐的新型物理检测技术。首先,采用了银镜反应原理,通过优化工艺,制备了不同银含量的三种银/二氧化硅纳米复合材料,并利用扫描电子显微镜(SEM)、X射线衍射(XRD)、紫外一可见吸收光谱、红外吸收光谱,对样品的表面形貌、结构、光学特性进行了分析表征。结果表明纳米银颗粒、二氧化硅颗粒大小均匀,二氧化硅颗粒被纳米银颗粒不同程度地包裹；银/二氧化硅纳米复合材料在可见光区域存在表面等离激元共振效应,在中红外区域有可能存在表面等离激元共振效应。其次,以硝酸钠水溶液为研究对象,重点研究了溶液蒸发过程中银/二氧化硅纳米复合材料对营养盐红外吸收光谱的影响。结果表明：水溶液中硝酸根的反对称伸缩振动模式分裂为两种模式A、B,模式A的振动频率约为1350cm-1(v1),模式B的振动频率约为1410cm-1(v2)；且随着水分的蒸发,两种振动模式的峰位均随硝酸根浓度的升高而有降低趋势,其半高宽也有不同程度变化,两种振动模式的吸收峰积分强度有不同程度的增大,其中纳米银颗粒含量较少的银/二氧化硅纳米复合材料对硝酸根的红外吸收具有更好的增强效果。这些结果表明银/二氧化硅纳米复合材料对硝酸根的红外吸收增强效应来自银/二氧化硅的界面效应。银/二氧化硅纳米复合材料对磷酸盐水溶液的红外吸收没有明显的影响,这是由于磷酸根本身的红外活性较弱造成的。再次,进一步研究了海水盐度和腐植酸对硝酸钠红外吸收光谱特性的影响。结果表明：随着盐度的增大,不同银纳米颗粒含量的银/二氧化硅纳米复合材料对硝酸根的红外吸收增强效应逐渐减小,硝酸根中心峰位、半高宽也有一定影响,其中二氧化硅颗粒被银纳米颗粒完全包裹的银/二氧化硅纳米复合材料对盐度的变化不敏感。腐殖酸对硝酸钠水溶液的红外光谱没有影响。本文初步研究了银/二氧化硅纳米复合材料对营养盐拉曼光谱的影响,结果发现复合材料对水溶液中的磷酸根的拉曼响应具有显著的增强效应,而对硝酸根的拉曼光谱没有明显影响,这是由于磷酸根的拉曼活性较强而硝酸根的拉曼活性较弱之外,银纳米颗粒在可见光区域具有明显的表面等离激元共振效应。海水盐度对硝酸根表面增强红外吸收光谱的影响表明：在测量海水环境下的营养盐含量时,盐度会对测量结果有很大的不利因素。总体来说,盐度对纳米壳结构的影响是最弱的,这个结果可以启发我们可以考虑使用纳米壳结构来尽量排除海水盐度的影响。更多还原

【Abstract】 Nutrient is one functional element in the ocean which has a close relationship with the biological process. In Oceanographic, traditional terms of nutrient elements of nitrogen, phosphorus, Silicon is one of the three primary elements. Undoubtedly nutrient plays an important role in the growth of marine organisms, however anomalous distribution of nutrients can also cause enormous stimulus on its growth. The seagrass eruption in Qingdao during the Beijing Olympic Games was the result of unusual content of the seawater nutrients. Rapid detection of the nutrients in the ocean becomes a pressing issue. This article researches the detection of nutrients in ocean exploration with surface-enhanced infrared/Raman Spectroscopy (SEIRAS: Surface-enhanced Infrared Absorption Spectroscopy; SERS:Surface-enhanced Raman Spectroscopy).In this article we prepare three silver/silica nano-composites with different silver content by the silver-mirror reaction. All these samples were characteristic with scanning electron microscope (SEM), x-ray diffraction (XRD), UV-visible absorption spectrum, infrared absorption spectroscopy to depict their surface morphology, structure of the sample characterization, optical characteristics. Results show that the nano silver particles, silicon dioxides have good uniformity in size and silicon dioxides are surround ed by nano-silver particles in different degree, but also silver/silica composites has the possibility of surface plasmon resonance in infra-red region.This article researches the infrared absorption spectrometry of nitrate in its evaporation process. Results indicate that the vibration modes of nitrate change with nitrate concentration, the half width, central wavenumber has changed in different degree. As the evaporation process, anti-symmetric stretch vibration of two nitrate absorption peak of the vibration mode integrals corresponding increase in area, all of reflecting composite films on nitrate anti-symmetric stretching vibration effects. We further study the effect of seawater salinity and the humic acid on infrared absorption spectrum properties of sodium nitrite and found that with the increase of salinity, the absorption peak integral area is gradually reduced. In this article, we also measured the infrared spectrometry of sodium phosphate and found that the Ag/SiO2composite material had strong enhanced function on its Raman spectrometry. The half band width and its peak integration area appear large change, while the central peak has no change. The infrared activity of sodium phosphate is weak, so the infrared spectra of is weak too.Results show that the aqueous silver/silica Nanocomposites in the different modes of vibration influence mainly from the silver nitrate/silica interface of hydration and nutrients, not much unlike that plasmon resonance.更多还原