Characterization of the Reducing Properties of Anaerobic Sediment Slurries Using Redox Indicators

摘要

The reduction of six redox indicators in anaerobic sediment slurries was studied by observing the disappearance of the color of the oxidized forms. The reaction kinetics were first-order in concentration of the oxidized form of the indicator and the reducing agents were sediment associated. The rate of indicator reduction reflects the standard potential of the indicator couple, the structure of the indicator moiety reduced, and the potential and capacity of reducing agents in the sediment slurry. The relative reduction rates of the indicators suggest that anaerobic sediment systems contain concentrations of mild reducing agents that are available to react rapidly with substrates that are easily reduced. However, more refractory substrates require strong reducing agents that are gradually produced, probably as a result of microbial metabolism.