Electron Transfer Capability Of Dissolved Organic Matter And Structure Activity Relationship

Dissolved organic matter (DOM) is a complicated compound, distributing widely in both terrestrial and aquatic environments. It is usually defined as the compound that is composed of organic material with different structure and molecular weight that can permeate0.45um filter membrane after extracted and oscillated by water (such as low molecular of free amino acid, carbohydrate, organic acid and high molecular enzyme, amino sugar, polyphenol and humus, etc). Humic substance (HS), which is one of the most important substances and has been widely studied, is a kind of colloform, whose surface is negatively charged, and can absorb pollutants. Meanwhile, with functional groups such as quinonoids and phenol, especially the electron transfer capacity of the quinonyl, HS displays significant redox property and related to the redox activity of heavy metal and organic pollutants oxidation. The DOM has complex structure and various functions, and its structure and redox property are focuses of research in soil science, environmental science, ecology and so on in recent years.This paper uses chronoamperometry method(for determining the electron transfer capability of DOM), combined with fluorescence spectroscopy, Fourier transform infrared, cyclic voltammetry, elementary analysis and UV spectrum to characterize the DOM, studies the impacts from pH and ionic strength on the electron transfer capacity of DOM, explores the characteristics of tea DOM electron transfer capacity and the DOM electron transfer ability in microbial complex system, and indicates the humification over the compost process by DOM electron transfer capacity. Following are the main conclusions:1. The DOM electron transfer capacity was influence by environmental factors. Research found that the electron transfer capacity is positively correlated with the pH and increasing in ionic strength first, but once the ionic strength reaches a certain value, the electronic transfer ability turns to be decreasing in it.2. The composition of the aqueous extract of tea differentiates due to different production process, which affects the content of the polyphenol, leading to various electron transfer ability of water soluble organics of different tea water soluble organics and different facilitating to the reduction of Fe (III) from its reversible parts.3. Microorganism electrochemical method methods was used to study the electron transfer capacity of four kinds of dissolved organic material:the anthraquinone-2,6-sulfonic acid sodium (AQDS), humic acid (HA), sewage sludge compost (SSC), and rice rhizosphere soil (RSS)). The results are consistent with electrochemical methods.4. Sample compost in each stage has electron transfer capacity, and the results show that the like-fulvic acid fluorescent peak strength is linear correlated with GI. The linear relationship between EAC and GI illustrates that the electron transfer capacity can be used as the humification index.