A rapid and simple electrochemical method for evaluating the electron transfer capacities of dissolved organic matter

作者：Yuan, Tian; Yuan, Yong; Zhou, Shungui^*; Li, Fangbai; Liu, Zhi; Zhuang, Li

来源：Journal of Soils and Sediments, 2011, 11(3): 467-473.

DOI：10.1007/s11368-010-0332-1

• Chronoamperometry
• Dissolved organic matter
• Electrochemistry
• Electron accepting capacities
• Electron donating capacities
• Electron transfer capacities

The evaluation of the electron transfer capacities (ETC) of DOM is important to understand their roles in microbial activity, pollution degradation, and metal mobility. Those currently used methods to quantify ETC, such as Zn and Fe3+ assays, are normally time consuming and usually require experience and skills to achieve reproducible results. The aim of this paper is to develop a rapid and simple approach to accurately and directly quantify the ETC of DOM.
DOM was extracted from sewage sludge compost. Cycle voltammetry (CV) was used to investigate the redox behavior of DOM derived from sludge compost. Chronoamperometry (CA) was employed to study the electron-accepting capacities (EAC) and electron-donating capacities (EDC) by applying fixed positive or negative potentials to a working electrode in a conventional three-electrode cell. For comparison, the EAC and EDC of DOM were also determined by chemical methods using Zn as the reductant and Fe3+ as the oxidant. The reversible electron transfer of DOM was studied electrochemically by CA with a multi-potential step technique.
The CV of sludge DOM displayed that a couple of quasi-reversible redox peaks with a formal potential of -0.866 V (vs. Ag/AgCl), demonstrating that the DOM was capable of reversibly transferring electrons. The value of EAC was determined by CA to be 361.6 mu mol(e-) (g C)(-1) at a potential of -0.6 V (vs. Ag/AgCl), and the value of initial EDC was 5.0 mu mol(e-) (g C)(-1) at a potential of +0.4 V (vs. Ag/AgCl). Both the values of EAC and EDC depended on the applied potentials on the working electrode. The results determined by the proposed method were comparable with those by using chemical methods.
A rapid electrochemical approach was employed to investigate the EAC and EDC of DOM extracted from sewage sludge compost. The acquired values of EAC and EDC were comparable with those measured by chemical methods using zinc as the reductant and ferric iron as the oxidant. The determination could be completed in tens of seconds, which was faster and more direct than conventional chemical methods.

• 出版日期2011-4
• 单位湖南农业大学; 广东省生态环境技术研究所