Insoluble/immobilized redox mediators for catalyzing anaerobic bio-reduction of contaminants

摘要

The soluble redox mediator had been employed for catalyzing anaerobic bio-reduction of recalcitrant contaminants such as azo compounds (mainly azo dyes), nitroaromatics, halogenated pollutants and high valence heavy metal, etc. However, the continuous dosing of soluble redox mediators would not only be economically unreasonable, but also have a risk of causing secondary pollution. Therefore the insoluble/immobilized redox mediators were widely studied in last decades trying to overcome above drawbacks. This paper reviewed insoluble redox mediators including carbonaceous (activated carbon, emerging activated carbon fiber, carbon nanotubes, graphene oxide and biochar) and natural materials (humin and henna plant), as well as immobilized redox mediators such as immobilizing model quinones or humic acid on calcium alginate, polyurethane foam, Poly(ethylene terephthalate) fiber, anion exchange resin, etc. The catalyzing performance, characteristics, disadvantages (if any) and lab-scale applications of those insoluble/immobilized RMs were critically discussed, in order to provide reference for the evolvement and promoting further utilizations of novel insoluble/immobilized redox mediators. In addition, future research needed was suggested towards the engineering application of insoluble/immobilized redox mediators.