Comparison of magnetite/reduced graphene oxide nanocomposites and magnetite nanoparticles on enhancing hydrogen production in dark fermentation

摘要

Magnetite/reduced graphene oxide nanocomposites (Fe_3O_4-rGO NCs) and magnetite nanoparticles (Fe_3O_4 NPs) were added to enhance biohydrogen (bioH_2) production in dark fermentation. Concentration of supplements from 10 to 100 mg/L was appropriate to enhance bioH_2 production, and inhibition appeared once concentration exceeded 100 mg/L. The best bioH_2 yield was 198.30 mL/g glucose at 100 mg/L Fe_3O_4 NPs and 225.60 mL/g glucose at 100 mg/L Fe_3O_4-rGO NCs, which was 42.97 and 62.65 higher than that in the blank group, respectively. Both Fe_3O_4 NPs and Fe_3O_4-rGO NCs could intensify butyrate-type fermentation and change the hydrogen-producing microorganism cells morphology, but the enhancement effect of Fe_3O_4-rGO NCs was superior. Microbial community structure analysis showed that Clostridium-sensu-stricto-1 became more dominant ultimately by Fe_3O_4-rGO NCs.