Enhanced degradation of phenolic compounds in coal gasification wastewater by activated carbon-Fe3O4 nanoparticles coupled with anaerobic co-metabolism

The aim of our research was to investigate the enhanced anaerobic degradation process of coal gasification wastewater (CGW) by conductive material activated carbon and Fe 3 O 4 nanoparticles (Fe 3 O 4 NPs) with the assistance of co-substrate. The optimal ratio of activated carbon to Fe 3 O 4 NPs (3:1) and the optimal addition of co-substrate (glucose concentration =1500 mg/L) were explored through batch tests. During the long-run reactor experiments, 1500 mg/L glucose was mixed into the influent, and activated carbon-Fe 3 O 4 NPs in a ratio of 3:1 were mixed into the anaerobic sludge. The concentration of total phenols in the effluent was kept around 50 mg/L, with a removal rate of 96% and an increase in methane production to 226 mL/day in the experimental reactor. Compared with the control reactor, the methane yield was increased by 64.6%. Toxicity analysis indicated that the toxicity of CGW can be greatly alleviated by conductive material activated carbon and Fe 3 O 4 NPs coupled with anaerobic co-digestion conditions. Microbial community analysis demonstrated that direct interspecies electron transfer (DIET) may have occurred between exoelectrogens ( Clostridium , Anaerolinea, Mesotoga, Synergistia) and methanogenic endoelectrogens ( Methanobacterium , Methanothrix ) for syntrophic metabolism through activated carbon-Fe 3 O 4 nanoparticles coupled with anaerobic co-metabolism.