| 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.
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