【作者】 张丽丽；

【导师】 朱淮武； 余德顺；

【作者基本信息】 贵州师范大学 ， 环境科学， 2008， 硕士

【摘要】 腐植酸是一类天然的多分散有机聚电解质生物大分子,是环境中天然有机物最重要的组成部分之一,能与环境中重金属离子、包括有机污染物在内的其它有机物及矿物质等发生相互作用,从而影响上述物质在环境中的迁移和传输、固定及积聚、化学反应性和生物利用度等重要的物理、化学、生物、地球化学行为及过程。由于其含有C、N、P、S等营养元素,是营养元素的储存库,可应用于肥料、土壤改良,是湖泊异养型微生物所需能源的主要提供者。由于其含有大量可电离的酚羟基及羧基,是湖泊水体pH的天然调节剂和控制因素及用于环境污染治理;并可作为抗病毒剂、重金属螯合剂、键合毒性化学品的聚合物和防电离辐射物质而有一定的医疗价值。因此对腐植酸的研究有非常重要的理论意义和现实意义,其基础研究和应用研究一直是相关研究的热点。本论文主要运用共振瑞利散射技术,结合紫外-可见光谱,荧光光谱、傅立叶红外、电导、电子透射电镜等现代分析化学方法和手段,对腐植酸及腐植酸与金属离子的相互作用进行了多手段、多角度地研究,取得了一些初步进展,其研究结论主要体现在以下几个方面:1.共振瑞利散射光谱技术因其实验仪器简单,方法灵敏度高、光谱信息丰富等特点而倍受广大研究者的关注。研究了一系列条件如pH、离子强度、不同酸介质、浓度及有机溶剂对国际腐植酸协会(IHSS)的标准土壤腐植酸共振瑞利散射和荧光光谱特性的影响,并用于腐植酸与部分重金属离子相互作用的研究,表明共振瑞利散射光谱完全可以应用于腐植酸及其与其它相关物质相互作用的研究中。2.初步研究了共振瑞利散射光谱技术用于腐植酸定量测定的可能,表明该技术有一定选择性,信号强度高,经进一步优化测定条件的研究,可望作为一种新的腐植酸定量分析技术。3.共振瑞利散射光谱并结合荧光光谱研究了腐植酸与金属离子(Cu2+、Pb2+、Zn2+、Cd2+、Fe3+、Al3+)在不同pH、不同金属离子浓度时的相互作用。结果表明Cu2+、Pb2+、Fe3+、Al3+与腐植酸相互作用较强,随金属离子浓度增加,荧光强度降低,以Cu2+较为明显,而共振瑞利散射均增强。Zn2+、Cd2+的作用弱。4. HA的紫外-可见光谱表现为无特征吸收,随着波长的增加紫外吸收逐渐降低,而且随着HA浓度的增加,紫外吸收也相应增大。5.三维荧光光谱表明腐植酸与金属离子相互作用发射波长发生蓝移,而激发波长基本不变。用修正型Stern-Volmer模型计算腐植酸与金属离子铜的络合稳定常数logK。6.结合傅立叶红外光谱技术探讨了HA与金属离子(Cu2+、Pb2+)的相互作用机理,表明腐植酸与金属离子作用主要发生在羧基位。7. HA与金属离子相互作用中溶液电导随金属离子浓度增加而增加,最后达到一个稳定值,其溶液电导率的拐点变化与相应RRS和荧光光谱强度的拐点发生变化的浓度范围一致。8.结合透射电镜讨论了各种条件下腐植酸及腐植酸-金属离子RRS产生及增强原因,认为聚集、聚集形成不均匀性及固态纳米颗粒、固液界面的形成及疏水性是RRS产生及增强的原因。更多还原

【Abstract】 Humic acid is a kind of natural multi-dispersions organic polyelectrolyte biological macromolecules and the most important component part of natural organic materials in environment. It can interact with heavy metal ions, other organic compounds including organic pollutants and minerals etc, therefore affecting migration and transmission, fixed and accumulation, chemical reactivity and bioavailability, and other important physical, chemical, biological, geochemical behavior and process of these substances in environment. Because of containing C, N, P, S, and other nutrients, it serve as the repository of nutrient elements that can be used in fertilizer and soil improvement and the main provider of energy for heterotrophic microorganisms in lakes. It is also the pH modifier of natural lake water and control factors for containing a considerable amount of phenolic hydroxyl and carboxyl group, which is helpful to environmental pollution government. at the same time, it has certain medical value when used as antivirals, heavy metal chelating agent, bonding toxic chemicals and polymers Anti-ionizing radiation substances. Therefore the study of humic acid has a very important theoretical and practical significance, and its basic and applied research has always been the hot spot in related research.In this paper, Resonance Rayleigh Scattering technology, combined with UV-visible spectroscopy, fluorescence spectroscopy, Fourier transform infrared, conductivity, electronic transmission electron microscopy, and other modern analytical chemistry methods were used to study humic acid and the interaction of humic acid and metal ions in multi-means and multi-angle and has made some preliminary progress. The conclusion mainly manifests in the following several aspects:1. Resonance Rayleigh Scattering spectroscopy catches much attention of extensive researchers for its simple experimental apparatus, high sensitivity, and richness in spectrum information and so on. The impact of a series of conditions such as pH, ionic strength, different acid medium and organic solvents on the Resonance Rayleigh Scattering and the fluorescence spectrum characteristic of standard soil humic acid of IHSS were studied and used in the humic acid and the partial heavy metal ion interaction research. Result indicated that resonance Resonance Rayleigh Scattering spectra can be definitely applied to humic acid and related material interaction research.2. Preliminary study on the possibility of Resonance Rayleigh Scattering spectra technology for the quantitative determination of humic acid showed that the technology has a certain selectivity, high signal intensity. Resonance Rayleigh Scattering spectra is expected to serve as a new quantitative analysis technology of humic acid through further optimization of determination condition.3. Resonance Rayleigh Scattering spectroscopy and fluorescence spectroscopy were used to study the interaction between humic acid and metal ions(Cu2+、Pb2+、Zn2+、Cd2+、Fe3+、Al3+)in different pH and ions concentration. Result showed that Cu2+、Pb2+、Fe3+、Al3+ have strong interaction with humic acid. Fluorescence intensity reduced along with the increasing metal ions concentration. Cu2+ is more obvious than other metal ions. Of these metal ions, Resonance Rayleigh Scattering is strengthened except Zn2+ and Cd2+.4. The ultraviolet-visible spectrum of humic acid showed no characteristic absorption, ultraviolet absorption gradually reduced with increase in wavelength, and along with the increase of concentration of HA, ultraviolet absorption increased correspondingly.5. The three dimensional fluorescence spectrum indicated that emission wavelength blue shift occurred when interaction happened, but the excitation wavelength basically unchanged. Modified Stern-Volmer model was used to compute stability constants logK of humic acid and Cu2+.6. Fourier infrared spectrum technology was used to discuss the interaction mechanism of humic acid and metal ions(Cu2+、Pb2+), result showed that the interaction mainly occurred in the carboxyl group position.7. Solution conductivity increased along with the increasing metal ion concentration in the interaction between humic acid and metal ions, ultimately achieved a stable value。The range of concentration which result in the inflection point change of solution conductivity, corresponding RRS and fluorescence spectrum intensity maintained consistent.8. Transmission electron microscope was also used to discuss the reason for RRS appearance and signal enhancement of humic acid and humic acid - metal ion under various conditions. Aggregation and the formation of unevenness and solid nanometer particles, the solid-liquid interface and hydrophobic were believed to be the main reason for the RRS occurrence and enhancement.更多还原