[Electron shuttling function of dissolved organic matter].
The redox reactive and electron shuttling function of dissolved organic matter (DOM) derived from sewage sludge were studied with Shewanella cinica D14(T) as driving force of electron transfer. The results indicated that sludge DOM initially served as terminal electron acceptor obtaining electrons from the respiratory chain of quinone-reducing bacteria D14(T), then it translated to reduced DOM which can donate electrons to Fe(III) again. The electron donating capacities (EDC) of DOM increased from initial capacity of 2.2-14 micromol x g(-1) to 253-347 micromol x g(-1) after DOM was reduced by D14(T). The cyclic voltammetry measurements and multiple reduction-oxidation cycles experiments of DOM showed that two pairs of redox peaks were clearly observed and the EDC remained at a level of 150-250 micromol x g(-1) after three reduction-oxidation cycles, indicating that DOM can be recyclably used for electron transfer. In the system of hydrous ferric oxide (HFO) reduction by S. cinica D14(T), the reductive dissolution speed was improved with the presence of DOM, since that DOM was capable of acting as an electron shuttle between S. cinica D14(T) and HFO. These results demonstrate the important role of DOM in electron transfer process, and bring out a new perspective about the functions of DOM in the environment.
College of Chemistry and Materials Science, Sichuan Normal University, Chengdu 610066, China. xuwei20070331@126.com
Wei
W
Xu
Pei
P
Hu
Shun-gui
SG
Zhou
Xiao-min
XM
Li
Yan-hong
YH
Li
D001673:Biodegradation, Environmental / Q000187:drug effects; D004579:Electron Transport; D004583:Electrons; D005290:Ferric Compounds / Q000737:chemistry; D006812:Humic Substances; D009930:Organic Chemicals / Q000378:metabolism*; D010084:Oxidation-Reduction; D012722:Sewage / Q000737:chemistry; D020592:Shewanella / Q000378:metabolism*; D012995:Solubility; D014865:Waste Disposal, Fluid / Q000379:methods
D005290:Ferric Compounds; D006812:Humic Substances; D009930:Organic Chemicals; D012722:Sewage; C000499:ferric oxide