Anaerobic biological treatment technology has been widely used for treating various organic pollutants due to less excessive sludge and recyclable energy, especially, good performance in removal of poisonous, harmful and refractory pollutants. However, the treatment rate of anaerobic biological process is usually relatively low. Redox mediators can improve the electron transfer rate in the redox process through continuous oxidation and reduction, promoting anaerobic degradation of pollutants. Quinones and humic acids are frequently used as redox mediators, which have achieved certain effects in catalytically enhancing the degradation of refractory pollutants. The characteristics and mechanism of redox mediators are discussed in this study, and their enhancement effects on anaerobic decolorization of azo dyes, denitrification and anaerobic degradation of polychlorinated biphenyls are summarized. Moreover, the future research direction of redox media is also proposed.

anaerobic degradation  /  redox mediators  /  electron transformation  /  catalytic enhancement